| Message ID | 1502473733.4936.17.camel@edumazet-glaptop3.roam.corp.google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Fri, 11 Aug 2017 10:48:53 -0700 > From: Eric Dumazet <edumazet@google.com> > > syzkaller got crashes with CONFIG_HARDENED_USERCOPY=y configs. > > Issue here is that recvfrom() can be used with user buffer of Z bytes, > and SO_PEEK_OFF of X bytes, from a skb with Y bytes, and following > condition : > > Z < X < Y > > kernel BUG at mm/usercopy.c:72! > invalid opcode: 0000 [#1] SMP KASAN > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 0 PID: 2917 Comm: syzkaller842281 Not tainted 4.13.0-rc3+ #16 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > task: ffff8801d2fa40c0 task.stack: ffff8801d1fe8000 > RIP: 0010:report_usercopy mm/usercopy.c:64 [inline] > RIP: 0010:__check_object_size+0x3ad/0x500 mm/usercopy.c:264 > RSP: 0018:ffff8801d1fef8a8 EFLAGS: 00010286 > RAX: 0000000000000078 RBX: ffffffff847102c0 RCX: 0000000000000000 > RDX: 0000000000000078 RSI: 1ffff1003a3fded5 RDI: ffffed003a3fdf09 > RBP: ffff8801d1fef998 R08: 0000000000000001 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d1ea480e > R13: fffffffffffffffa R14: ffffffff84710280 R15: dffffc0000000000 > FS: 0000000001360880(0000) GS:ffff8801dc000000(0000) > knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00000000202ecfe4 CR3: 00000001d1ff8000 CR4: 00000000001406f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > check_object_size include/linux/thread_info.h:108 [inline] > check_copy_size include/linux/thread_info.h:139 [inline] > copy_to_iter include/linux/uio.h:105 [inline] > copy_linear_skb include/net/udp.h:371 [inline] > udpv6_recvmsg+0x1040/0x1af0 net/ipv6/udp.c:395 > inet_recvmsg+0x14c/0x5f0 net/ipv4/af_inet.c:793 > sock_recvmsg_nosec net/socket.c:792 [inline] > sock_recvmsg+0xc9/0x110 net/socket.c:799 > SYSC_recvfrom+0x2d6/0x570 net/socket.c:1788 > SyS_recvfrom+0x40/0x50 net/socket.c:1760 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > > Fixes: b65ac44674dd ("udp: try to avoid 2 cache miss on dequeue") > Signed-off-by: Eric Dumazet <edumazet@google.com> Applied, thanks Eric.
diff --git a/include/net/udp.h b/include/net/udp.h index cc8036987dcb..e9b1d1eacb59 100644 --- a/include/net/udp.h +++ b/include/net/udp.h @@ -368,6 +368,8 @@ static inline int copy_linear_skb(struct sk_buff *skb, int len, int off, { int n, copy = len - off; + if (copy < 0) + return -EINVAL; n = copy_to_iter(skb->data + off, copy, to); if (n == copy) return 0;