linux/tools/testing/selftests/bpf/verifier/xdp_direct_packet_access.c

1469 lines
48 KiB
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{
"XDP pkt read, pkt_end mangling, bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R3 pointer arithmetic on pkt_end",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"XDP pkt read, pkt_end mangling, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_ALU64_IMM(BPF_SUB, BPF_REG_3, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R3 pointer arithmetic on pkt_end",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
},
{
"XDP pkt read, pkt_data' > pkt_end, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' > pkt_end, bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' > pkt_end, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' > pkt_end, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' > pkt_end, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end > pkt_data', good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end > pkt_data', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end > pkt_data', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end > pkt_data', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end > pkt_data', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' < pkt_end, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' < pkt_end, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' < pkt_end, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' < pkt_end, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' < pkt_end, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end < pkt_data', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end < pkt_data', bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end < pkt_data', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end < pkt_data', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end < pkt_data', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' >= pkt_end, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' >= pkt_end, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' >= pkt_end, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 0),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' >= pkt_end, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' >= pkt_end, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end >= pkt_data', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end >= pkt_data', bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end >= pkt_data', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end >= pkt_data', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end >= pkt_data', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' <= pkt_end, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' <= pkt_end, bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' <= pkt_end, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' <= pkt_end, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data' <= pkt_end, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end <= pkt_data', good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end <= pkt_data', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end <= pkt_data', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 0),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end <= pkt_data', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_end <= pkt_data', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' > pkt_data, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' > pkt_data, bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' > pkt_data, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' > pkt_data, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' > pkt_data, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data > pkt_meta', good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data > pkt_meta', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data > pkt_meta', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data > pkt_meta', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data > pkt_meta', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' < pkt_data, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' < pkt_data, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' < pkt_data, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' < pkt_data, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' < pkt_data, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data < pkt_meta', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data < pkt_meta', bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data < pkt_meta', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 0),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data < pkt_meta', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data < pkt_meta', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLT, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' >= pkt_data, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' >= pkt_data, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' >= pkt_data, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 0),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' >= pkt_data, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' >= pkt_data, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data >= pkt_meta', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data >= pkt_meta', bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data >= pkt_meta', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data >= pkt_meta', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data >= pkt_meta', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' <= pkt_data, corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' <= pkt_data, bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -4),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' <= pkt_data, bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' <= pkt_data, corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 9),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -9),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_meta' <= pkt_data, corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLE, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data <= pkt_meta', good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data <= pkt_meta', corner case -1, bad access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
bpf: Fix the off-by-two error in range markings The first commit cited below attempts to fix the off-by-one error that appeared in some comparisons with an open range. Due to this error, arithmetically equivalent pieces of code could get different verdicts from the verifier, for example (pseudocode): // 1. Passes the verifier: if (data + 8 > data_end) return early read *(u64 *)data, i.e. [data; data+7] // 2. Rejected by the verifier (should still pass): if (data + 7 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The attempted fix, however, shifts the range by one in a wrong direction, so the bug not only remains, but also such piece of code starts failing in the verifier: // 3. Rejected by the verifier, but the check is stricter than in #1. if (data + 8 >= data_end) return early read *(u64 *)data, i.e. [data; data+7] The change performed by that fix converted an off-by-one bug into off-by-two. The second commit cited below added the BPF selftests written to ensure than code chunks like #3 are rejected, however, they should be accepted. This commit fixes the off-by-two error by adjusting new_range in the right direction and fixes the tests by changing the range into the one that should actually fail. Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns") Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
2021-11-30 18:16:07 +00:00
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data <= pkt_meta', bad access 2",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 0),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, -5),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.errstr = "R1 offset is outside of the packet",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data <= pkt_meta', corner case, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 7),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -7),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
{
"XDP pkt read, pkt_data <= pkt_meta', corner case +1, good access",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
offsetof(struct xdp_md, data_meta)),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.result = ACCEPT,
.prog_type = BPF_PROG_TYPE_XDP,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},