Catch integer overflow rather than silently truncating while

parsing MASK: strings in ASN1_STRING_set_default_mask_asc(3).
Issue noticed by tb@, patch by me, two additional #include lines from tb@.
OK tb@.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/lib/libcrypto/asn1/a_strnid.c b/src/lib/libcrypto/asn1/a_strnid.c
index 08043f723b..f14daa602c 100644
--- a/src/lib/libcrypto/asn1/a_strnid.c
+++ b/src/lib/libcrypto/asn1/a_strnid.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: a_strnid.c,v 1.23 2021/12/11 22:58:48 schwarze Exp $ */
+/* $OpenBSD: a_strnid.c,v 1.24 2021/12/13 14:06:17 schwarze Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 1999.
  */
@@ -56,7 +56,10 @@
  *
  */
 
+#include <errno.h>
+#include <limits.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include <openssl/asn1.h>
@@ -106,11 +109,17 @@ ASN1_STRING_set_default_mask_asc(const char *p)
 {
         unsigned long mask;
         char *end;
+        int save_errno;
 
         if (strncmp(p, "MASK:", 5) == 0) {
                 if (p[5] == '\0')
                         return 0;
+                save_errno = errno;
+                errno = 0;
                 mask = strtoul(p + 5, &end, 0);
+                if (errno == ERANGE && mask == ULONG_MAX)
+                        return 0;
+                errno = save_errno;
                 if (*end != '\0')
                         return 0;
         } else if (strcmp(p, "nombstr") == 0)