diff mbox series

[net,2/2] Revert "netfilter: conntrack: fix bug in for_each_sctp_chunk"

Message ID 20230131133158.4052-3-pablo@netfilter.org (mailing list archive)
State Accepted
Commit bd0e06f0def75ba26572a94e5350324474a55562
Delegated to: Netdev Maintainers
Headers show
Series [net,1/2] netfilter: br_netfilter: disable sabotage_in hook after first suppression | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Pull request is its own cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 669 this patch: 669
netdev/cc_maintainers fail 1 blamed authors not CCed: sriram.yagnaraman@est.tech; 4 maintainers not CCed: sriram.yagnaraman@est.tech kadlec@netfilter.org coreteam@netfilter.org fw@strlen.de
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
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: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Pablo Neira Ayuso Jan. 31, 2023, 1:31 p.m. UTC 
From: Florian Westphal <fw@strlen.de>

There is no bug.  If sch->length == 0, this would result in an infinite
loop, but first caller, do_basic_checks(), errors out in this case.

After this change, packets with bogus zero-length chunks are no longer
detected as invalid, so revert & add comment wrt. 0 length check.

Fixes: 98ee00774525 ("netfilter: conntrack: fix bug in for_each_sctp_chunk")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_proto_sctp.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 945dd40e7077..011d414038ea 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -142,10 +142,11 @@  static void sctp_print_conntrack(struct seq_file *s, struct nf_conn *ct)
 }
 #endif
 
+/* do_basic_checks ensures sch->length > 0, do not use before */
 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count)	\
 for ((offset) = (dataoff) + sizeof(struct sctphdr), (count) = 0;	\
-	((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))) &&	\
-	(sch)->length;	\
+	(offset) < (skb)->len &&					\
+	((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch)));	\
 	(offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
 
 /* Some validity checks to make sure the chunks are fine */