netfilter: nfnetlink_osf: fix possible bogus match in nf_osf_find()

[ Upstream commit 559c36c ] nf_osf_find() incorrectly returns true on mismatch, this leads to copying uninitialized memory area in nft_osf which can be used to leak stale kernel stack data to userspace. Fixes: 22c7652 ("netfilter: nft_osf: Add version option support") Signed-off-by: Pablo Neira Ayuso <[email protected]> Signed-off-by: Florian Westphal <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
SolidRun · Sep 28, 2022 · 633c81c · 633c81c
1 parent 510ea9e
commit 633c81c
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c
@@ -269,6 +269,7 @@ bool nf_osf_find(const struct sk_buff *skb,
 	struct nf_osf_hdr_ctx ctx;
 	const struct tcphdr *tcp;
 	struct tcphdr _tcph;
+	bool found = false;
 
 	memset(&ctx, 0, sizeof(ctx));
 
@@ -283,10 +284,11 @@ bool nf_osf_find(const struct sk_buff *skb,
 
 		data->genre = f->genre;
 		data->version = f->version;
+		found = true;
 		break;
 	}
 
-	return true;
+	return found;
 }
 EXPORT_SYMBOL_GPL(nf_osf_find);