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| author | Eric Dumazet <edumazet@google.com> | 2018-04-05 06:39:28 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-04-05 15:16:15 -0400 |
| commit | b95211e066fc3494b7c115060b2297b4ba21f025 (patch) | |
| tree | d8b8bd64f9e05a06872fb07ef6934654ca5db5fd | |
| parent | 9cb726a212a82c88c98aa9f0037fd04777cd8fe5 (diff) | |
| download | linux-b95211e066fc3494b7c115060b2297b4ba21f025.tar.bz2 | |
ipv6: sit: better validate user provided tunnel names
Use dev_valid_name() to make sure user does not provide illegal
device name.
syzbot caught the following bug :
BUG: KASAN: stack-out-of-bounds in strlcpy include/linux/string.h:300 [inline]
BUG: KASAN: stack-out-of-bounds in ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254
Write of size 33 at addr ffff8801b64076d8 by task syzkaller932654/4453
CPU: 0 PID: 4453 Comm: syzkaller932654 Not tainted 4.16.0+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x1b9/0x29f lib/dump_stack.c:53
print_address_description+0x6c/0x20b mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
memcpy+0x37/0x50 mm/kasan/kasan.c:303
strlcpy include/linux/string.h:300 [inline]
ipip6_tunnel_locate+0x63b/0xaa0 net/ipv6/sit.c:254
ipip6_tunnel_ioctl+0xe71/0x241b net/ipv6/sit.c:1221
dev_ifsioc+0x43e/0xb90 net/core/dev_ioctl.c:334
dev_ioctl+0x69a/0xcc0 net/core/dev_ioctl.c:525
sock_ioctl+0x47e/0x680 net/socket.c:1015
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x1cf/0x1650 fs/ioctl.c:684
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:701
SYSC_ioctl fs/ioctl.c:708 [inline]
SyS_ioctl+0x24/0x30 fs/ioctl.c:706
do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
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>
| -rw-r--r-- | net/ipv6/sit.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 1522bcfd253f..2afce37a7177 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -250,11 +250,13 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net, if (!create) goto failed; - if (parms->name[0]) + if (parms->name[0]) { + if (!dev_valid_name(parms->name)) + goto failed; strlcpy(name, parms->name, IFNAMSIZ); - else + } else { strcpy(name, "sit%d"); - + } dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN, ipip6_tunnel_setup); if (!dev) |