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authorDave Jones <davej@codemonkey.org.uk>2016-12-22 11:16:22 -0500
committerDavid S. Miller <davem@davemloft.net>2016-12-23 12:20:39 -0500
commita98f91758995cb59611e61318dddd8a6956b52c3 (patch)
tree9ce2ae63a0a413dd929e724325e4cdf18f6aad9c
parent39b2dd765e0711e1efd1d1df089473a8dd93ad48 (diff)
downloadlinux-stericsson-a98f91758995cb59611e61318dddd8a6956b52c3.tar.gz
ipv6: handle -EFAULT from skb_copy_bits
By setting certain socket options on ipv6 raw sockets, we can confuse the length calculation in rawv6_push_pending_frames triggering a BUG_ON. RIP: 0010:[<ffffffff817c6390>] [<ffffffff817c6390>] rawv6_sendmsg+0xc30/0xc40 RSP: 0018:ffff881f6c4a7c18 EFLAGS: 00010282 RAX: 00000000fffffff2 RBX: ffff881f6c681680 RCX: 0000000000000002 RDX: ffff881f6c4a7cf8 RSI: 0000000000000030 RDI: ffff881fed0f6a00 RBP: ffff881f6c4a7da8 R08: 0000000000000000 R09: 0000000000000009 R10: ffff881fed0f6a00 R11: 0000000000000009 R12: 0000000000000030 R13: ffff881fed0f6a00 R14: ffff881fee39ba00 R15: ffff881fefa93a80 Call Trace: [<ffffffff8118ba23>] ? unmap_page_range+0x693/0x830 [<ffffffff81772697>] inet_sendmsg+0x67/0xa0 [<ffffffff816d93f8>] sock_sendmsg+0x38/0x50 [<ffffffff816d982f>] SYSC_sendto+0xef/0x170 [<ffffffff816da27e>] SyS_sendto+0xe/0x10 [<ffffffff81002910>] do_syscall_64+0x50/0xa0 [<ffffffff817f7cbc>] entry_SYSCALL64_slow_path+0x25/0x25 Handle by jumping to the failure path if skb_copy_bits gets an EFAULT. Reproducer: #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #define LEN 504 int main(int argc, char* argv[]) { int fd; int zero = 0; char buf[LEN]; memset(buf, 0, LEN); fd = socket(AF_INET6, SOCK_RAW, 7); setsockopt(fd, SOL_IPV6, IPV6_CHECKSUM, &zero, 4); setsockopt(fd, SOL_IPV6, IPV6_DSTOPTS, &buf, LEN); sendto(fd, buf, 1, 0, (struct sockaddr *) buf, 110); } Signed-off-by: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv6/raw.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 291ebc260e70..ea89073c8247 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -591,7 +591,11 @@ static int rawv6_push_pending_frames(struct sock *sk, struct flowi6 *fl6,
}
offset += skb_transport_offset(skb);
- BUG_ON(skb_copy_bits(skb, offset, &csum, 2));
+ err = skb_copy_bits(skb, offset, &csum, 2);
+ if (err < 0) {
+ ip6_flush_pending_frames(sk);
+ goto out;
+ }
/* in case cksum was not initialized */
if (unlikely(csum))