diff mbox series

[net,2/2] netfilter: nf_tables_ipv6: consider network offset in netdev/egress validation

Message ID 20240828214708.619261-3-pablo@netfilter.org (mailing list archive)
State Accepted
Commit 70c261d500951cf3ea0fcf32651aab9a65a91471
Delegated to: Netdev Maintainers
Headers show
Series [net,1/2] netfilter: nf_tables: restore IP sanity checks for netdev/egress | expand

Checks

Context Check Description
netdev/series_format success Pull request is its own cover letter
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/build_tools success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers fail 1 blamed authors not CCed: lukas@wunner.de; 3 maintainers not CCed: coreteam@netfilter.org lukas@wunner.de kadlec@netfilter.org
netdev/build_clang success Errors and warnings before: 16 this patch: 16
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: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 18 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-08-29--09-00 (tests: 710)

Commit Message

Pablo Neira Ayuso Aug. 28, 2024, 9:47 p.m. UTC 
From netdev/egress, skb->len can include the ethernet header, therefore,
subtract network offset from skb->len when validating IPv6 packet length.

Fixes: 42df6e1d221d ("netfilter: Introduce egress hook")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_tables_ipv6.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/include/net/netfilter/nf_tables_ipv6.h b/include/net/netfilter/nf_tables_ipv6.h
index 467d59b9e533..a0633eeaec97 100644
--- a/include/net/netfilter/nf_tables_ipv6.h
+++ b/include/net/netfilter/nf_tables_ipv6.h
@@ -31,8 +31,8 @@  static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt)
 	struct ipv6hdr *ip6h, _ip6h;
 	unsigned int thoff = 0;
 	unsigned short frag_off;
+	u32 pkt_len, skb_len;
 	int protohdr;
-	u32 pkt_len;
 
 	ip6h = skb_header_pointer(pkt->skb, skb_network_offset(pkt->skb),
 				  sizeof(*ip6h), &_ip6h);
@@ -43,7 +43,8 @@  static inline int __nft_set_pktinfo_ipv6_validate(struct nft_pktinfo *pkt)
 		return -1;
 
 	pkt_len = ntohs(ip6h->payload_len);
-	if (pkt_len + sizeof(*ip6h) > pkt->skb->len)
+	skb_len = pkt->skb->len - skb_network_offset(pkt->skb);
+	if (pkt_len + sizeof(*ip6h) > skb_len)
 		return -1;
 
 	protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, &flags);