Add checks to X509_NAME_oneline()

Sanity check field lengths and sums to avoid potential overflows and reject
excessively large X509_NAME structures.

Issue reported by Guido Vranken.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 77076dc944f76e821e4eae3a6563b853ce00c0ed)

Conflicts:
	crypto/x509/x509_err.c
	crypto/x509/x509_obj.c

3 files changed, 19 insertions, 2 deletions

diff --git a/crypto/x509/x509.h b/crypto/x509/x509.h
index 99337b849a..fc613ce635 100644
--- a/crypto/x509/x509.h
+++ b/crypto/x509/x509.h
@@ -1305,6 +1305,7 @@ void ERR_load_X509_strings(void);
 # define X509_R_LOADING_CERT_DIR                          103
 # define X509_R_LOADING_DEFAULTS                          104
 # define X509_R_METHOD_NOT_SUPPORTED                      124
+# define X509_R_NAME_TOO_LONG                             134
 # define X509_R_NEWER_CRL_NOT_NEWER                       132
 # define X509_R_NO_CERT_SET_FOR_US_TO_VERIFY              105
 # define X509_R_NO_CRL_NUMBER                             130
diff --git a/crypto/x509/x509_err.c b/crypto/x509/x509_err.c
index 43cde18e49..1e779fefd9 100644
--- a/crypto/x509/x509_err.c
+++ b/crypto/x509/x509_err.c
@@ -151,6 +151,7 @@ static ERR_STRING_DATA X509_str_reasons[] = {
     {ERR_REASON(X509_R_LOADING_CERT_DIR), "loading cert dir"},
     {ERR_REASON(X509_R_LOADING_DEFAULTS), "loading defaults"},
     {ERR_REASON(X509_R_METHOD_NOT_SUPPORTED), "method not supported"},
+    {ERR_REASON(X509_R_NAME_TOO_LONG), "name too long"},
     {ERR_REASON(X509_R_NEWER_CRL_NOT_NEWER), "newer crl not newer"},
     {ERR_REASON(X509_R_NO_CERT_SET_FOR_US_TO_VERIFY),
      "no cert set for us to verify"},
diff --git a/crypto/x509/x509_obj.c b/crypto/x509/x509_obj.c
index 500c9dfa54..f7daac25e9 100644
--- a/crypto/x509/x509_obj.c
+++ b/crypto/x509/x509_obj.c
@@ -63,6 +63,13 @@
 #include <openssl/x509.h>
 #include <openssl/buffer.h>
 
+/*
+ * Limit to ensure we don't overflow: much greater than
+ * anything enountered in practice.
+ */
+
+#define NAME_ONELINE_MAX    (1024 * 1024)
+
 char *X509_NAME_oneline(X509_NAME *a, char *buf, int len)
 {
     X509_NAME_ENTRY *ne;
@@ -112,6 +119,10 @@ char *X509_NAME_oneline(X509_NAME *a, char *buf, int len)
 
         type = ne->value->type;
         num = ne->value->length;
+        if (num > NAME_ONELINE_MAX) {
+            X509err(X509_F_X509_NAME_ONELINE, X509_R_NAME_TOO_LONG);
+            goto end;
+        }
         q = ne->value->data;
 #ifdef CHARSET_EBCDIC
         if (type == V_ASN1_GENERALSTRING ||
@@ -156,6 +167,10 @@ char *X509_NAME_oneline(X509_NAME *a, char *buf, int len)
 
         lold = l;
         l += 1 + l1 + 1 + l2;
+        if (l > NAME_ONELINE_MAX) {
+            X509err(X509_F_X509_NAME_ONELINE, X509_R_NAME_TOO_LONG);
+            goto end;
+        }
         if (b != NULL) {
             if (!BUF_MEM_grow(b, l + 1))
                 goto err;
@@ -208,7 +223,7 @@ char *X509_NAME_oneline(X509_NAME *a, char *buf, int len)
     return (p);
  err:
     X509err(X509_F_X509_NAME_ONELINE, ERR_R_MALLOC_FAILURE);
-    if (b != NULL)
-        BUF_MEM_free(b);
+ end:
+    BUF_MEM_free(b);
     return (NULL);
 }