[ovs-dev] [PATCH] lib: added check to prevent int overflow

[Toms Atteka]

If enough large input is given ofpact_finish will fail.
Check was added and error message returned.

Basic manual testing performed.

Reported-by:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12972
Signed-off-by: Toms Atteka <cpp.code.lv at gmail.com>
---
 lib/learn.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/learn.c b/lib/learn.c
index 642ce18..5b168e4 100644
--- a/lib/learn.c
+++ b/lib/learn.c
@@ -455,6 +455,11 @@ learn_parse__(char *orig, char *arg, const struct ofputil_port_map *port_map,
             learn = ofpacts->header;
         }
     }
+
+    if ((char *)ofpbuf_tail(ofpacts) - (char *)ofpacts->header > UINT16_MAX) {
+        return xasprintf("input too big");
+    }
+
     ofpact_finish_LEARN(ofpacts, &learn);
 
     return NULL;
-- 
2.7.4