diff --git a/include/linux/bpf.h b/include/linux/bpf.h index e3b82ce51445..6eb0b180d33b 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -332,7 +332,10 @@ enum bpf_type_flag { */ MEM_ALLOC = BIT(2 + BPF_BASE_TYPE_BITS), - __BPF_TYPE_LAST_FLAG = MEM_ALLOC, + /* MEM is in user address space. */ + MEM_USER = BIT(3 + BPF_BASE_TYPE_BITS), + + __BPF_TYPE_LAST_FLAG = MEM_USER, }; /* Max number of base types. */ @@ -588,7 +591,7 @@ struct bpf_verifier_ops { const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id); + u32 *next_btf_id, enum bpf_type_flag *flag); }; struct bpf_prog_offload_ops { @@ -1780,7 +1783,7 @@ static inline bool bpf_tracing_btf_ctx_access(int off, int size, int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id); + u32 *next_btf_id, enum bpf_type_flag *flag); bool btf_struct_ids_match(struct bpf_verifier_log *log, const struct btf *btf, u32 id, int off, const struct btf *need_btf, u32 need_type_id); diff --git a/include/linux/btf.h b/include/linux/btf.h index b12cfe3b12bb..f6c43dd513fa 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -238,6 +238,11 @@ static inline bool btf_type_is_var(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_VAR; } +static inline bool btf_type_is_type_tag(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG; +} + /* union is only a special case of struct: * all its offsetof(member) == 0 */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index b2a248956100..b983cee8d196 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4886,6 +4886,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, const char *tname = prog->aux->attach_func_name; struct bpf_verifier_log *log = info->log; const struct btf_param *args; + const char *tag_value; u32 nr_args, arg; int i, ret; @@ -5038,6 +5039,13 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, info->btf = btf; info->btf_id = t->type; t = btf_type_by_id(btf, t->type); + + if (btf_type_is_type_tag(t)) { + tag_value = __btf_name_by_offset(btf, t->name_off); + if (strcmp(tag_value, "user") == 0) + info->reg_type |= MEM_USER; + } + /* skip modifiers */ while (btf_type_is_modifier(t)) { info->btf_id = t->type; @@ -5064,12 +5072,12 @@ enum bpf_struct_walk_result { static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, - u32 *next_btf_id) + u32 *next_btf_id, enum bpf_type_flag *flag) { u32 i, moff, mtrue_end, msize = 0, total_nelems = 0; const struct btf_type *mtype, *elem_type = NULL; const struct btf_member *member; - const char *tname, *mname; + const char *tname, *mname, *tag_value; u32 vlen, elem_id, mid; again: @@ -5253,7 +5261,8 @@ error: } if (btf_type_is_ptr(mtype)) { - const struct btf_type *stype; + const struct btf_type *stype, *t; + enum bpf_type_flag tmp_flag = 0; u32 id; if (msize != size || off != moff) { @@ -5262,9 +5271,19 @@ error: mname, moff, tname, off, size); return -EACCES; } + + /* check __user tag */ + t = btf_type_by_id(btf, mtype->type); + if (btf_type_is_type_tag(t)) { + tag_value = __btf_name_by_offset(btf, t->name_off); + if (strcmp(tag_value, "user") == 0) + tmp_flag = MEM_USER; + } + stype = btf_type_skip_modifiers(btf, mtype->type, &id); if (btf_type_is_struct(stype)) { *next_btf_id = id; + *flag = tmp_flag; return WALK_PTR; } } @@ -5291,13 +5310,14 @@ error: int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype __maybe_unused, - u32 *next_btf_id) + u32 *next_btf_id, enum bpf_type_flag *flag) { + enum bpf_type_flag tmp_flag = 0; int err; u32 id; do { - err = btf_struct_walk(log, btf, t, off, size, &id); + err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag); switch (err) { case WALK_PTR: @@ -5305,6 +5325,7 @@ int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, * we're done. */ *next_btf_id = id; + *flag = tmp_flag; return PTR_TO_BTF_ID; case WALK_SCALAR: return SCALAR_VALUE; @@ -5349,6 +5370,7 @@ bool btf_struct_ids_match(struct bpf_verifier_log *log, const struct btf *need_btf, u32 need_type_id) { const struct btf_type *type; + enum bpf_type_flag flag; int err; /* Are we already done? */ @@ -5359,7 +5381,7 @@ again: type = btf_type_by_id(btf, id); if (!type) return false; - err = btf_struct_walk(log, btf, type, off, 1, &id); + err = btf_struct_walk(log, btf, type, off, 1, &id, &flag); if (err != WALK_STRUCT) return false; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dcf065ec2774..1ae41d0cf96c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -536,7 +536,7 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn) static const char *reg_type_str(struct bpf_verifier_env *env, enum bpf_reg_type type) { - char postfix[16] = {0}, prefix[16] = {0}; + char postfix[16] = {0}, prefix[32] = {0}; static const char * const str[] = { [NOT_INIT] = "?", [SCALAR_VALUE] = "inv", @@ -570,9 +570,11 @@ static const char *reg_type_str(struct bpf_verifier_env *env, } if (type & MEM_RDONLY) - strncpy(prefix, "rdonly_", 16); + strncpy(prefix, "rdonly_", 32); if (type & MEM_ALLOC) - strncpy(prefix, "alloc_", 16); + strncpy(prefix, "alloc_", 32); + if (type & MEM_USER) + strncpy(prefix, "user_", 32); snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s", prefix, str[base_type(type)], postfix); @@ -1547,14 +1549,15 @@ static void mark_reg_not_init(struct bpf_verifier_env *env, static void mark_btf_ld_reg(struct bpf_verifier_env *env, struct bpf_reg_state *regs, u32 regno, enum bpf_reg_type reg_type, - struct btf *btf, u32 btf_id) + struct btf *btf, u32 btf_id, + enum bpf_type_flag flag) { if (reg_type == SCALAR_VALUE) { mark_reg_unknown(env, regs, regno); return; } mark_reg_known_zero(env, regs, regno); - regs[regno].type = PTR_TO_BTF_ID; + regs[regno].type = PTR_TO_BTF_ID | flag; regs[regno].btf = btf; regs[regno].btf_id = btf_id; } @@ -4152,6 +4155,7 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, struct bpf_reg_state *reg = regs + regno; const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id); const char *tname = btf_name_by_offset(reg->btf, t->name_off); + enum bpf_type_flag flag = 0; u32 btf_id; int ret; @@ -4171,9 +4175,16 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, return -EACCES; } + if (reg->type & MEM_USER) { + verbose(env, + "R%d is ptr_%s access user memory: off=%d\n", + regno, tname, off); + return -EACCES; + } + if (env->ops->btf_struct_access) { ret = env->ops->btf_struct_access(&env->log, reg->btf, t, - off, size, atype, &btf_id); + off, size, atype, &btf_id, &flag); } else { if (atype != BPF_READ) { verbose(env, "only read is supported\n"); @@ -4181,14 +4192,14 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env, } ret = btf_struct_access(&env->log, reg->btf, t, off, size, - atype, &btf_id); + atype, &btf_id, &flag); } if (ret < 0) return ret; if (atype == BPF_READ && value_regno >= 0) - mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id); + mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag); return 0; } @@ -4201,6 +4212,7 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, { struct bpf_reg_state *reg = regs + regno; struct bpf_map *map = reg->map_ptr; + enum bpf_type_flag flag = 0; const struct btf_type *t; const char *tname; u32 btf_id; @@ -4238,12 +4250,12 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env, return -EACCES; } - ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id); + ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id, &flag); if (ret < 0) return ret; if (value_regno >= 0) - mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id); + mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag); return 0; } @@ -4444,7 +4456,8 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn if (err < 0) return err; - err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, &btf_id); + err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf, + &btf_id); if (err) verbose_linfo(env, insn_idx, "; "); if (!err && t == BPF_READ && value_regno >= 0) { diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index fbc896323bec..d0e54e30658a 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -145,7 +145,8 @@ static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id) + u32 *next_btf_id, + enum bpf_type_flag *flag) { const struct btf_type *state; s32 type_id; @@ -162,7 +163,8 @@ static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, return -EACCES; } - err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id); + err = btf_struct_access(log, btf, t, off, size, atype, next_btf_id, + flag); if (err < 0) return err; diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index b60c9fd7147e..f79ab942f03b 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -96,12 +96,14 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf, const struct btf_type *t, int off, int size, enum bpf_access_type atype, - u32 *next_btf_id) + u32 *next_btf_id, + enum bpf_type_flag *flag) { size_t end; if (atype == BPF_READ) - return btf_struct_access(log, btf, t, off, size, atype, next_btf_id); + return btf_struct_access(log, btf, t, off, size, atype, next_btf_id, + flag); if (t != tcp_sock_type) { bpf_log(log, "only read is supported\n");