This is a note to let you know that I've just added the patch titled ipv6: handle -EFAULT from skb_copy_bits to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv6-handle-efault-from-skb_copy_bits.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Jan 12 21:37:26 CET 2017 From: Dave Jones <davej@xxxxxxxxxxxxxxxxx> Date: Thu, 22 Dec 2016 11:16:22 -0500 Subject: ipv6: handle -EFAULT from skb_copy_bits From: Dave Jones <davej@xxxxxxxxxxxxxxxxx> [ Upstream commit a98f91758995cb59611e61318dddd8a6956b52c3 ] 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@xxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/raw.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -589,7 +589,11 @@ static int rawv6_push_pending_frames(str } 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)) Patches currently in stable-queue which might be from davej@xxxxxxxxxxxxxxxxx are queue-4.9/ipv6-handle-efault-from-skb_copy_bits.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html