| Message ID | 20250123145746.785768-1-syoshida@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5066293b9b7046a906eff60e3949a887ae185a43 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] vxlan: Fix uninit-value in vxlan_vnifilter_dump() | expand |
On Thu, Jan 23, 2025 at 11:57:46PM +0900, Shigeru Yoshida wrote: > KMSAN reported an uninit-value access in vxlan_vnifilter_dump() [1]. > > If the length of the netlink message payload is less than > sizeof(struct tunnel_msg), vxlan_vnifilter_dump() accesses bytes > beyond the message. This can lead to uninit-value access. Fix this by > returning an error in such situations. [...] > Fixes: f9c4bb0b245c ("vxlan: vni filtering support on collect metadata device") > Reported-by: syzkaller <syzkaller@googlegroups.com> > Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Reviewed-by: Ido Schimmel <idosch@nvidia.com>
On Thu, 23 Jan 2025 23:57:46 +0900 Shigeru Yoshida wrote: > + if (cb->nlh->nlmsg_len < nlmsg_msg_size(sizeof(struct tunnel_msg))) { > + NL_SET_ERR_MSG(cb->extack, "Invalid msg length"); > + return -EINVAL; > + } > + > tmsg = nlmsg_data(cb->nlh); We really should have a better helper for combined message length validation and nlmsg_data(). I'll add this to our list of outstanding cleanup tasks..
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Thu, 23 Jan 2025 23:57:46 +0900 you wrote: > KMSAN reported an uninit-value access in vxlan_vnifilter_dump() [1]. > > If the length of the netlink message payload is less than > sizeof(struct tunnel_msg), vxlan_vnifilter_dump() accesses bytes > beyond the message. This can lead to uninit-value access. Fix this by > returning an error in such situations. > > [...] Here is the summary with links: - [net] vxlan: Fix uninit-value in vxlan_vnifilter_dump() https://git.kernel.org/netdev/net/c/5066293b9b70 You are awesome, thank you!
diff --git a/drivers/net/vxlan/vxlan_vnifilter.c b/drivers/net/vxlan/vxlan_vnifilter.c index d2023e7131bd..6e6e9f05509a 100644 --- a/drivers/net/vxlan/vxlan_vnifilter.c +++ b/drivers/net/vxlan/vxlan_vnifilter.c @@ -411,6 +411,11 @@ static int vxlan_vnifilter_dump(struct sk_buff *skb, struct netlink_callback *cb struct tunnel_msg *tmsg; struct net_device *dev; + if (cb->nlh->nlmsg_len < nlmsg_msg_size(sizeof(struct tunnel_msg))) { + NL_SET_ERR_MSG(cb->extack, "Invalid msg length"); + return -EINVAL; + } + tmsg = nlmsg_data(cb->nlh); if (tmsg->flags & ~TUNNEL_MSG_VALID_USER_FLAGS) {
KMSAN reported an uninit-value access in vxlan_vnifilter_dump() [1]. If the length of the netlink message payload is less than sizeof(struct tunnel_msg), vxlan_vnifilter_dump() accesses bytes beyond the message. This can lead to uninit-value access. Fix this by returning an error in such situations. [1] BUG: KMSAN: uninit-value in vxlan_vnifilter_dump+0x328/0x920 drivers/net/vxlan/vxlan_vnifilter.c:422 vxlan_vnifilter_dump+0x328/0x920 drivers/net/vxlan/vxlan_vnifilter.c:422 rtnl_dumpit+0xd5/0x2f0 net/core/rtnetlink.c:6786 netlink_dump+0x93e/0x15f0 net/netlink/af_netlink.c:2317 __netlink_dump_start+0x716/0xd60 net/netlink/af_netlink.c:2432 netlink_dump_start include/linux/netlink.h:340 [inline] rtnetlink_dump_start net/core/rtnetlink.c:6815 [inline] rtnetlink_rcv_msg+0x1256/0x14a0 net/core/rtnetlink.c:6882 netlink_rcv_skb+0x467/0x660 net/netlink/af_netlink.c:2542 rtnetlink_rcv+0x35/0x40 net/core/rtnetlink.c:6944 netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline] netlink_unicast+0xed6/0x1290 net/netlink/af_netlink.c:1347 netlink_sendmsg+0x1092/0x1230 net/netlink/af_netlink.c:1891 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:726 ____sys_sendmsg+0x7f4/0xb50 net/socket.c:2583 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2637 __sys_sendmsg net/socket.c:2669 [inline] __do_sys_sendmsg net/socket.c:2674 [inline] __se_sys_sendmsg net/socket.c:2672 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2672 x64_sys_call+0x3878/0x3d90 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd9/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:4110 [inline] slab_alloc_node mm/slub.c:4153 [inline] kmem_cache_alloc_node_noprof+0x800/0xe80 mm/slub.c:4205 kmalloc_reserve+0x13b/0x4b0 net/core/skbuff.c:587 __alloc_skb+0x347/0x7d0 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1323 [inline] netlink_alloc_large_skb+0xa5/0x280 net/netlink/af_netlink.c:1196 netlink_sendmsg+0xac9/0x1230 net/netlink/af_netlink.c:1866 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x330/0x3d0 net/socket.c:726 ____sys_sendmsg+0x7f4/0xb50 net/socket.c:2583 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2637 __sys_sendmsg net/socket.c:2669 [inline] __do_sys_sendmsg net/socket.c:2674 [inline] __se_sys_sendmsg net/socket.c:2672 [inline] __x64_sys_sendmsg+0x211/0x3e0 net/socket.c:2672 x64_sys_call+0x3878/0x3d90 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xd9/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f CPU: 0 UID: 0 PID: 30991 Comm: syz.4.10630 Not tainted 6.12.0-10694-gc44daa7e3c73 #29 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 Fixes: f9c4bb0b245c ("vxlan: vni filtering support on collect metadata device") Reported-by: syzkaller <syzkaller@googlegroups.com> Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> --- drivers/net/vxlan/vxlan_vnifilter.c | 5 +++++ 1 file changed, 5 insertions(+)