On Wed, Jan 04, 2023 at 06:44:21PM +0100, Stefano Brivio wrote:
Reported by Coverity (CWE-606, Untrusted loop bound),
and actually
harmless because we'll exit the option-scanning loop if the remaining
length is not enough for a new option, instead of reading past the
header.
In any case, it looks like a good idea to explicitly check for
reasonable values of option lengths.
Signed-off-by: Stefano Brivio <sbrivio(a)redhat.com>
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
---
tcp.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tcp.c b/tcp.c
index 26037b3..1e0a338 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1117,6 +1117,10 @@ static int tcp_opt_get(const char *opts, size_t len, uint8_t
type_find,
break;
default:
type = *(opts++);
+
+ if (*(uint8_t *)opts < 2 || *(uint8_t *)opts > len)
+ return -1;
+
optlen = *(opts++) - 2;
len -= 2;
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson