linux/net
Eric Biggers 3fd8712707 strparser: initialize all callbacks
commit bbb03029a8 ("strparser: Generalize strparser") added more
function pointers to 'struct strp_callbacks'; however, kcm_attach() was
not updated to initialize them.  This could cause the ->lock() and/or
->unlock() function pointers to be set to garbage values, causing a
crash in strp_work().

Fix the bug by moving the callback structs into static memory, so
unspecified members are zeroed.  Also constify them while we're at it.

This bug was found by syzkaller, which encountered the following splat:

    IP: 0x55
    PGD 3b1ca067
    P4D 3b1ca067
    PUD 3b12f067
    PMD 0

    Oops: 0010 [#1] SMP KASAN
    Dumping ftrace buffer:
       (ftrace buffer empty)
    Modules linked in:
    CPU: 2 PID: 1194 Comm: kworker/u8:1 Not tainted 4.13.0-rc4-next-20170811 #2
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Workqueue: kstrp strp_work
    task: ffff88006bb0e480 task.stack: ffff88006bb10000
    RIP: 0010:0x55
    RSP: 0018:ffff88006bb17540 EFLAGS: 00010246
    RAX: dffffc0000000000 RBX: ffff88006ce4bd60 RCX: 0000000000000000
    RDX: 1ffff1000d9c97bd RSI: 0000000000000000 RDI: ffff88006ce4bc48
    RBP: ffff88006bb17558 R08: ffffffff81467ab2 R09: 0000000000000000
    R10: ffff88006bb17438 R11: ffff88006bb17940 R12: ffff88006ce4bc48
    R13: ffff88003c683018 R14: ffff88006bb17980 R15: ffff88003c683000
    FS:  0000000000000000(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 0000000000000055 CR3: 000000003c145000 CR4: 00000000000006e0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    Call Trace:
     process_one_work+0xbf3/0x1bc0 kernel/workqueue.c:2098
     worker_thread+0x223/0x1860 kernel/workqueue.c:2233
     kthread+0x35e/0x430 kernel/kthread.c:231
     ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
    Code:  Bad RIP value.
    RIP: 0x55 RSP: ffff88006bb17540
    CR2: 0000000000000055
    ---[ end trace f0e4920047069cee ]---

Here is a C reproducer (requires CONFIG_BPF_SYSCALL=y and
CONFIG_AF_KCM=y):

    #include <linux/bpf.h>
    #include <linux/kcm.h>
    #include <linux/types.h>
    #include <stdint.h>
    #include <sys/ioctl.h>
    #include <sys/socket.h>
    #include <sys/syscall.h>
    #include <unistd.h>

    static const struct bpf_insn bpf_insns[3] = {
        { .code = 0xb7 }, /* BPF_MOV64_IMM(0, 0) */
        { .code = 0x95 }, /* BPF_EXIT_INSN() */
    };

    static const union bpf_attr bpf_attr = {
        .prog_type = 1,
        .insn_cnt = 2,
        .insns = (uintptr_t)&bpf_insns,
        .license = (uintptr_t)"",
    };

    int main(void)
    {
        int bpf_fd = syscall(__NR_bpf, BPF_PROG_LOAD,
                             &bpf_attr, sizeof(bpf_attr));
        int inet_fd = socket(AF_INET, SOCK_STREAM, 0);
        int kcm_fd = socket(AF_KCM, SOCK_DGRAM, 0);

        ioctl(kcm_fd, SIOCKCMATTACH,
              &(struct kcm_attach) { .fd = inet_fd, .bpf_fd = bpf_fd });
    }

Fixes: bbb03029a8 ("strparser: Generalize strparser")
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Tom Herbert <tom@quantonium.net>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-24 21:57:50 -07:00
..
6lowpan
9p Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-07-15 12:00:42 -07:00
802 net: introduce __skb_put_[zero, data, u8] 2017-06-20 13:30:14 -04:00
8021q net: add netlink_ext_ack argument to rtnl_link_ops.validate 2017-06-26 23:13:22 -04:00
appletalk networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
atm net: atm: make atmdev_ops const 2017-08-09 22:43:50 -07:00
ax25 net, ax25: convert ax25_cb.refcount from atomic_t to refcount_t 2017-07-04 22:35:19 +01:00
batman-adv Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-09 16:28:45 -07:00
bluetooth Bluetooth: kfree tmp rather than an alias to it 2017-08-11 21:19:46 +02:00
bpf
bridge rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
caif net: convert sock.sk_wmem_alloc from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
can rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
ceph libceph: make RECOVERY_DELETES feature create a new interval 2017-08-01 16:46:45 +02:00
core xdp: remove net_device names from xdp_redirect tracepoint 2017-08-24 11:59:37 -07:00
dcb rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
dccp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 17:06:42 -07:00
decnet rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
dns_resolver
dsa dsa: remove unused net_device arg from handlers 2017-08-21 10:39:11 -07:00
ethernet networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
hsr net: add netlink_ext_ack argument to rtnl_link_ops.newlink 2017-06-26 23:13:21 -04:00
ieee802154 net: add netlink_ext_ack argument to rtnl_link_ops.validate 2017-06-26 23:13:22 -04:00
ife
ipv4 gre: remove duplicated assignment of iph 2017-08-23 22:36:03 -07:00
ipv6 ipv6: Use multipath hash from flow info if available 2017-08-24 18:21:17 -07:00
ipx net, ipx: convert ipx_route.refcnt from atomic_t to refcount_t 2017-07-04 22:35:17 +01:00
irda irda: do not leak initialized list.dev to userspace 2017-08-18 16:21:51 -07:00
iucv iucv: Convert sk_wmem_alloc accesses to refcount_t. 2017-07-03 02:31:22 -07:00
kcm strparser: initialize all callbacks 2017-08-24 21:57:50 -07:00
key Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-15 20:23:23 -07:00
l2tp Revert "l2tp: constify inet6_protocol structures" 2017-08-01 10:03:17 -07:00
l3mdev
lapb net, lapb: convert lapb_cb.refcnt from atomic_t to refcount_t 2017-07-04 22:35:16 +01:00
llc net, llc: convert llc_sap.refcnt from atomic_t to refcount_t 2017-07-04 22:35:15 +01:00
mac80211 mac80211: add api to start ba session timer expired flow 2017-08-09 09:49:42 +03:00
mac802154 net: Fix inconsistent teardown and release of private netdev state. 2017-06-07 15:53:24 -04:00
mpls rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
ncsi networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
netfilter net: ipv6: add second dif to inet6 socket lookups 2017-08-07 11:39:22 -07:00
netlabel
netlink net: convert sock.sk_refcnt from atomic_t to refcount_t 2017-07-01 07:39:08 -07:00
netrom net, netrom: convert nr_node.refcount from atomic_t to refcount_t 2017-07-04 22:35:17 +01:00
nfc NFC: Add sockaddr length checks before accessing sa_family in bind handlers 2017-06-23 00:38:31 +02:00
openvswitch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 17:06:42 -07:00
packet Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-10 12:11:16 -07:00
phonet rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
psample networking: make skb_put & friends return void pointers 2017-06-16 11:48:39 -04:00
qrtr rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
rds Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-09 16:28:45 -07:00
rfkill net: rfkill: gpio: Switch to devm_acpi_dev_add_driver_gpios() 2017-06-13 11:07:51 +02:00
rose
rxrpc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 17:06:42 -07:00
sched net: sched: use kvmalloc() for class hash tables 2017-08-22 14:37:24 -07:00
sctp Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 17:06:42 -07:00
smc net/smc: synchronize buffer usage with device 2017-07-29 11:22:58 -07:00
strparser strparser: initialize all callbacks 2017-08-24 21:57:50 -07:00
sunrpc NFS client bugfixes for 4.13 2017-07-21 16:26:01 -07:00
switchdev net: switchdev: Remove bridge bypass support from switchdev 2017-08-07 14:48:48 -07:00
tipc net: tipc: constify genl_ops 2017-08-23 22:31:38 -07:00
tls TLS: Fix length check in do_tls_getsockopt_tx() 2017-07-06 10:58:19 +01:00
unix Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-08-21 17:06:42 -07:00
vmw_vsock net: manual clean code which call skb_put_[data:zero] 2017-06-20 13:30:15 -04:00
wimax
wireless netlink validation fixes for nl80211 2017-07-07 11:35:55 +01:00
x25 X25: constify null_x25_address 2017-08-03 09:13:51 -07:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2017-08-21 09:29:47 -07:00
compat.c get_compat_bpf_fprog(): don't copyin field-by-field 2017-07-04 13:14:34 -04:00
Kconfig tls: kernel TLS support 2017-06-15 12:12:40 -04:00
Makefile tls: kernel TLS support 2017-06-15 12:12:40 -04:00
socket.c net: fixes for skb_send_sock 2017-08-16 11:27:52 -07:00
sysctl_net.c