Fix length checks in X509_cmp_time to avoid out-of-bounds reads.
Also tighten X509_cmp_time to reject more than three fractional
seconds in the time; and to reject trailing garbage after the offset.
CVE-2015-1789
(Imported from upstream's 9bc3665ac9e3c36f7762acd3691e1115d250b030)
Change-Id: I2091b2d1b691c177d58dc7960e2e7eb4c97b1f69
Reviewed-on: https://boringssl-review.googlesource.com/5124
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/x509/x509_vfy.c b/crypto/x509/x509_vfy.c
index 2ba9c84..f53f279 100644
--- a/crypto/x509/x509_vfy.c
+++ b/crypto/x509/x509_vfy.c
@@ -1829,49 +1829,89 @@
ASN1_TIME atm;
long offset;
char buff1[24],buff2[24],*p;
- int i,j;
+ int i, j, remaining;
p=buff1;
- i=ctm->length;
+ remaining = ctm->length;
str=(char *)ctm->data;
+ /* Note that the following (historical) code allows much more slack in
+ * the time format than RFC5280. In RFC5280, the representation is
+ * fixed:
+ * UTCTime: YYMMDDHHMMSSZ
+ * GeneralizedTime: YYYYMMDDHHMMSSZ */
if (ctm->type == V_ASN1_UTCTIME)
{
- if ((i < 11) || (i > 17)) return 0;
+ /* YYMMDDHHMM[SS]Z or YYMMDDHHMM[SS](+-)hhmm */
+ int min_length = sizeof("YYMMDDHHMMZ") - 1;
+ int max_length = sizeof("YYMMDDHHMMSS+hhmm") - 1;
+ if (remaining < min_length || remaining > max_length)
+ return 0;
memcpy(p,str,10);
p+=10;
str+=10;
+ remaining -= 10;
}
else
{
- if (i < 13) return 0;
+ /* YYYYMMDDHHMM[SS[.fff]]Z or YYYYMMDDHHMM[SS[.f[f[f]]]](+-)hhmm */
+ int min_length = sizeof("YYYYMMDDHHMMZ") - 1;
+ int max_length = sizeof("YYYYMMDDHHMMSS.fff+hhmm") - 1;
+ if (remaining < min_length || remaining > max_length)
+ return 0;
memcpy(p,str,12);
p+=12;
str+=12;
+ remaining -= 12;
}
if ((*str == 'Z') || (*str == '-') || (*str == '+'))
{ *(p++)='0'; *(p++)='0'; }
else
{
+ /* SS (seconds) */
+ if (remaining < 2)
+ return 0;
*(p++)= *(str++);
*(p++)= *(str++);
- /* Skip any fractional seconds... */
- if (*str == '.')
+ remaining -= 2;
+ /* Skip any (up to three) fractional seconds...
+ * TODO(emilia): in RFC5280, fractional seconds are forbidden.
+ * Can we just kill them altogether? */
+ if (remaining && *str == '.')
{
str++;
- while ((*str >= '0') && (*str <= '9')) str++;
+ remaining--;
+ for (i = 0; i < 3 && remaining; i++, str++, remaining--)
+ {
+ if (*str < '0' || *str > '9')
+ break;
+ }
}
}
*(p++)='Z';
*(p++)='\0';
+ /* We now need either a terminating 'Z' or an offset. */
+ if (!remaining)
+ return 0;
if (*str == 'Z')
+ {
+ if (remaining != 1)
+ return 0;
offset=0;
+ }
else
{
+ /* (+-)HHMM */
if ((*str != '+') && (*str != '-'))
return 0;
+ /* Historical behaviour: the (+-)hhmm offset is forbidden in RFC5280. */
+ if (remaining != 5)
+ return 0;
+ if (str[1] < '0' || str[1] > '9' || str[2] < '0' || str[2] > '9' ||
+ str[3] < '0' || str[3] > '9' || str[4] < '0' || str[4] > '9')
+ return 0;
offset=((str[1]-'0')*10+(str[2]-'0'))*60;
offset+=(str[3]-'0')*10+(str[4]-'0');
if (*str == '-')
