[PATCH v2 1/9] net/tcp: fix TCP options processing

Mikhail Kshevetskiy mikhail.kshevetskiy at iopsys.eu
Fri Jul 5 17:04:23 CEST 2024


Current TCP code may miss an option if TCP_O_NOP option was used before
it for proper aligning.

Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
---
 net/tcp.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/tcp.c b/net/tcp.c
index a713e1dd609..c9bcd364ee3 100644
--- a/net/tcp.c
+++ b/net/tcp.c
@@ -476,7 +476,7 @@ void tcp_parse_options(uchar *o, int o_len)
 	 * NOPs are options with a zero length, and thus are special.
 	 * All other options have length fields.
 	 */
-	for (p = o; p < (o + o_len); p = p + p[1]) {
+	for (p = o; p < (o + o_len); ) {
 		if (!p[1])
 			return; /* Finished processing options */
 
@@ -491,12 +491,14 @@ void tcp_parse_options(uchar *o, int o_len)
 		case TCP_O_TS:
 			tsopt = (struct tcp_t_opt *)p;
 			rmt_timestamp = tsopt->t_snd;
-			return;
+			break;
 		}
 
 		/* Process optional NOPs */
 		if (p[0] == TCP_O_NOP)
 			p++;
+		else
+			p += p[1];
 	}
 }
 
-- 
2.39.2



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