diff mbox series

[07/11] ip_vti: fix potential slab-use-after-free in decode_session6

Message ID 20230815095310.3310160-8-steffen.klassert@secunet.com (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series [01/11] net: xfrm: Fix xfrm_address_filter OOB read | expand

Checks

Context Check Description
netdev/series_format warning Pull request is its own cover letter; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1330 this patch: 1330
netdev/cc_maintainers warning 3 maintainers not CCed: pabeni@redhat.com dsahern@kernel.org edumazet@google.com
netdev/build_clang success Errors and warnings before: 1353 this patch: 1353
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1353 this patch: 1353
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 14 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Steffen Klassert Aug. 15, 2023, 9:53 a.m. UTC 
From: Zhengchao Shao <shaozhengchao@huawei.com>

When ip_vti device is set to the qdisc of the sfb type, the cb field
of the sent skb may be modified during enqueuing. Then,
slab-use-after-free may occur when ip_vti device sends IPv6 packets.
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in
_decode_session6.") showed, xfrm_decode_session was originally intended
only for the receive path. IP6CB(skb)->nhoff is not set during
transmission. Therefore, set the cb field in the skb to 0 before
sending packets.

Fixes: f855691975bb ("xfrm6: Fix the nexthdr offset in _decode_session6.")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/ip_vti.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 53bfd8af6920..d1e7d0ceb7ed 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -287,12 +287,12 @@  static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):
-		xfrm_decode_session(skb, &fl, AF_INET);
 		memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
+		xfrm_decode_session(skb, &fl, AF_INET);
 		break;
 	case htons(ETH_P_IPV6):
-		xfrm_decode_session(skb, &fl, AF_INET6);
 		memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
+		xfrm_decode_session(skb, &fl, AF_INET6);
 		break;
 	default:
 		goto tx_err;