More complete input validation of X509_check_mumble

[openssl.git] / crypto / x509v3 / v3_utl.c

diff --git a/crypto/x509v3/v3_utl.c b/crypto/x509v3/v3_utl.c
index 7a4bd459604cbdcfa688da4f45a79439bb3680b8..ea260f3c9532bb6b726e6eeccae4129e693af1e0 100644 (file)
--- a/crypto/x509v3/v3_utl.c
+++ b/crypto/x509v3/v3_utl.c
@@ -572,11 +572,46 @@ typedef int (*equal_fn)(const unsigned char *pattern, size_t pattern_len,
                        const unsigned char *subject, size_t subject_len,
                        unsigned int flags);
 
+/* Skip pattern prefix to match "wildcard" subject */
+static void skip_prefix(const unsigned char **p, size_t *plen,
+                       const unsigned char *subject, size_t subject_len,
+                       unsigned int flags)
+       {
+       const unsigned char *pattern = *p;
+       size_t pattern_len = *plen;
+
+       /*
+        * If subject starts with a leading '.' followed by more octets, and
+        * pattern is longer, compare just an equal-length suffix with the
+        * full subject (starting at the '.'), provided the prefix contains
+        * no NULs.
+        */
+       if ((flags & _X509_CHECK_FLAG_DOT_SUBDOMAINS) == 0)
+               return;
+
+       while (pattern_len > subject_len && *pattern)
+               {
+               if ((flags & X509_CHECK_FLAG_SINGLE_LABEL_SUBDOMAINS) &&
+                   *pattern == '.')
+                       break;
+               ++pattern;
+               --pattern_len;
+               }
+
+       /* Skip if entire prefix acceptable */
+       if (pattern_len == subject_len)
+               {
+               *p = pattern;
+               *plen = pattern_len;
+               }
+       }
+
 /* Compare while ASCII ignoring case. */
 static int equal_nocase(const unsigned char *pattern, size_t pattern_len,
                        const unsigned char *subject, size_t subject_len,
-                       unsigned int unused_flags)
+                       unsigned int flags)
        {
+       skip_prefix(&pattern, &pattern_len, subject, subject_len, flags);
        if (pattern_len != subject_len)
                return 0;
        while (pattern_len)
@@ -605,11 +640,9 @@ static int equal_nocase(const unsigned char *pattern, size_t pattern_len,
 /* Compare using memcmp. */
 static int equal_case(const unsigned char *pattern, size_t pattern_len,
                      const unsigned char *subject, size_t subject_len,
-                     unsigned int unused_flags)
+                     unsigned int flags)
 {
-       /* The pattern must not contain NUL characters. */
-       if (memchr(pattern, '\0', pattern_len) != NULL)
-               return 0;
+       skip_prefix(&pattern, &pattern_len, subject, subject_len, flags);
        if (pattern_len != subject_len)
                return 0;
        return !memcmp(pattern, subject, pattern_len);
@@ -797,7 +830,14 @@ static int equal_wildcard(const unsigned char *pattern, size_t pattern_len,
                          const unsigned char *subject, size_t subject_len,
                          unsigned int flags)
        {
-       const unsigned char *star = valid_star(pattern, pattern_len, flags);
+       const unsigned char *star = NULL;
+
+       /*
+        * Subject names starting with '.' can only match a wildcard pattern
+        * via a subject sub-domain pattern suffix match.
+        */
+       if (!(subject_len > 1 && subject[0] == '.'))
+               star = valid_star(pattern, pattern_len, flags);
        if (star == NULL)
                return equal_nocase(pattern, pattern_len,
                                    subject, subject_len, flags);
@@ -851,6 +891,9 @@ static int do_x509_check(X509 *x, const unsigned char *chk, size_t chklen,
        int alt_type;
        int san_present = 0;
        equal_fn equal;
+
+       /* See below, this flag is internal-only */
+       flags &= ~_X509_CHECK_FLAG_DOT_SUBDOMAINS;
        if (check_type == GEN_EMAIL)
                {
                cnid = NID_pkcs9_emailAddress;
@@ -860,6 +903,9 @@ static int do_x509_check(X509 *x, const unsigned char *chk, size_t chklen,
        else if (check_type == GEN_DNS)
                {
                cnid = NID_commonName;
+               /* Implicit client-side DNS sub-domain pattern */
+               if (chklen > 1 && chk[0] == '.')
+                       flags |= _X509_CHECK_FLAG_DOT_SUBDOMAINS;
                alt_type = V_ASN1_IA5STRING;
                if (flags & X509_CHECK_FLAG_NO_WILDCARDS)
                        equal = equal_nocase;
@@ -926,18 +972,46 @@ static int do_x509_check(X509 *x, const unsigned char *chk, size_t chklen,
 int X509_check_host(X509 *x, const unsigned char *chk, size_t chklen,
                                        unsigned int flags)
        {
+       if (chk == NULL)
+               return -2;
+       /*
+        * Embedded NULs are disallowed, except as the last character of a
+        * string of length 2 or more (tolerate caller including terminating
+        * NUL in string length).
+        */
+       if (chklen == 0)
+               chklen = strlen((char *)chk);
+       else if (memchr(chk, '\0', chklen > 1 ? chklen-1 : chklen))
+               return -2;
+       if (chklen > 1 && chk[chklen-1] == '\0')
+               --chklen;
        return do_x509_check(x, chk, chklen, flags, GEN_DNS);
        }
 
 int X509_check_email(X509 *x, const unsigned char *chk, size_t chklen,
                                        unsigned int flags)
        {
+       if (chk == NULL)
+               return -2;
+       /*
+        * Embedded NULs are disallowed, except as the last character of a
+        * string of length 2 or more (tolerate caller including terminating
+        * NUL in string length).
+        */
+       if (chklen == 0)
+               chklen = strlen((char *)chk);
+       else if (memchr(chk, '\0', chklen > 1 ? chklen-1 : chklen))
+               return -2;
+       if (chklen > 1 && chk[chklen-1] == '\0')
+               --chklen;
        return do_x509_check(x, chk, chklen, flags, GEN_EMAIL);
        }
 
 int X509_check_ip(X509 *x, const unsigned char *chk, size_t chklen,
                                        unsigned int flags)
        {
+       if (chk == NULL)
+               return -2;
        return do_x509_check(x, chk, chklen, flags, GEN_IPADD);
        }
 
@@ -945,6 +1019,8 @@ int X509_check_ip_asc(X509 *x, const char *ipasc, unsigned int flags)
        {
        unsigned char ipout[16];
        int iplen;
+       if (ipasc == NULL)
+               return -2;
        iplen = a2i_ipadd(ipout, ipasc);
        if (iplen == 0)
                return -2;