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| author | Eric Dumazet <edumazet@google.com> | 2018-05-07 09:02:25 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-05-08 00:11:40 -0400 |
| commit | 2c5d5b13c6eb79f5677e206b8aad59b3a2097f60 (patch) | |
| tree | c78efc86bd9f146e06001ad737d083962bad9c18 /net/llc | |
| parent | 895b61760bec60e0b5dbfc4d9e2c8e6299da8f81 (diff) | |
| download | lwn-2c5d5b13c6eb79f5677e206b8aad59b3a2097f60.tar.gz lwn-2c5d5b13c6eb79f5677e206b8aad59b3a2097f60.zip | |
llc: better deal with too small mtu
syzbot loves to set very small mtu on devices, since it brings joy.
We must make llc_ui_sendmsg() fool proof.
usercopy: Kernel memory overwrite attempt detected to wrapped address (offset 0, size 18446612139802320068)!
kernel BUG at mm/usercopy.c:100!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
(ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 17464 Comm: syz-executor1 Not tainted 4.17.0-rc3+ #36
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:usercopy_abort+0xbb/0xbd mm/usercopy.c:88
RSP: 0018:ffff8801868bf800 EFLAGS: 00010282
RAX: 000000000000006c RBX: ffffffff87d2fb00 RCX: 0000000000000000
RDX: 000000000000006c RSI: ffffffff81610731 RDI: ffffed0030d17ef6
RBP: ffff8801868bf858 R08: ffff88018daa4200 R09: ffffed003b5c4fb0
R10: ffffed003b5c4fb0 R11: ffff8801dae27d87 R12: ffffffff87d2f8e0
R13: ffffffff87d2f7a0 R14: ffffffff87d2f7a0 R15: ffffffff87d2f7a0
FS: 00007f56a14ac700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2bc21000 CR3: 00000001abeb1000 CR4: 00000000001426f0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000030602
Call Trace:
check_bogus_address mm/usercopy.c:153 [inline]
__check_object_size+0x5d9/0x5d9 mm/usercopy.c:256
check_object_size include/linux/thread_info.h:108 [inline]
check_copy_size include/linux/thread_info.h:139 [inline]
copy_from_iter_full include/linux/uio.h:121 [inline]
memcpy_from_msg include/linux/skbuff.h:3305 [inline]
llc_ui_sendmsg+0x4b1/0x1530 net/llc/af_llc.c:941
sock_sendmsg_nosec net/socket.c:629 [inline]
sock_sendmsg+0xd5/0x120 net/socket.c:639
__sys_sendto+0x3d7/0x670 net/socket.c:1789
__do_sys_sendto net/socket.c:1801 [inline]
__se_sys_sendto net/socket.c:1797 [inline]
__x64_sys_sendto+0xe1/0x1a0 net/socket.c:1797
do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455979
RSP: 002b:00007f56a14abc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f56a14ac6d4 RCX: 0000000000455979
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000018
RBP: 000000000072bea0 R08: 00000000200012c0 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000548 R14: 00000000006fbf60 R15: 0000000000000000
Code: 55 c0 e8 c0 55 bb ff ff 75 c8 48 8b 55 c0 4d 89 f9 ff 75 d0 4d 89 e8 48 89 d9 4c 89 e6 41 56 48 c7 c7 80 fa d2 87 e8 a0 0b a3 ff <0f> 0b e8 95 55 bb ff e8 c0 a8 f7 ff 8b 95 14 ff ff ff 4d 89 e8
RIP: usercopy_abort+0xbb/0xbd mm/usercopy.c:88 RSP: ffff8801868bf800
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/llc')
| -rw-r--r-- | net/llc/af_llc.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c index cb80ebb38311..1beeea9549fa 100644 --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -930,6 +930,9 @@ static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) if (size > llc->dev->mtu) size = llc->dev->mtu; copied = size - hdrlen; + rc = -EINVAL; + if (copied < 0) + goto release; release_sock(sk); skb = sock_alloc_send_skb(sk, size, noblock, &rc); lock_sock(sk); |