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@.

diff --git a/lib/libcrypto/asn1/a_strnid.c b/lib/libcrypto/asn1/a_strnid.c
index 08043f7..f14daa6 100644 (file)
--- a/lib/libcrypto/asn1/a_strnid.c
+++ b/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)