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authorEric Dumazet <edumazet@google.com>2018-04-05 06:39:28 -0700
committerDavid S. Miller <davem@davemloft.net>2018-04-05 15:16:15 -0400
commitb95211e066fc3494b7c115060b2297b4ba21f025 (patch)
treed8b8bd64f9e05a06872fb07ef6934654ca5db5fd /net/ipv6/sit.c
parentip_tunnel: better validate user provided tunnel names (diff)
downloadlinux-dev-b95211e066fc3494b7c115060b2297b4ba21f025.tar.xz
linux-dev-b95211e066fc3494b7c115060b2297b4ba21f025.zip
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>
Diffstat (limited to 'net/ipv6/sit.c')
-rw-r--r--net/ipv6/sit.c8
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)