Use more efficient way to locate end of an ASN1 structure.

1 files changed, 59 insertions, 4 deletions

diff --git a/crypto/asn1/tasn_dec.c b/crypto/asn1/tasn_dec.c
index 46df79519f..39a9d5a9aa 100644
--- a/crypto/asn1/tasn_dec.c
+++ b/crypto/asn1/tasn_dec.c
@@ -66,6 +66,7 @@
 #include <openssl/err.h>
 
 static int asn1_check_eoc(const unsigned char **in, long len);
+static int asn1_find_end(const unsigned char **in, long len, char inf);
 
 static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,
 				char inf, int tag, int aclass);
@@ -848,7 +849,7 @@ static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
 		/* If indefinite length constructed find the real end */
 		if (inf)
 			{
-			if (!asn1_collect(NULL, &p, plen, inf, -1, -1))
+			if (!asn1_find_end(&p, plen, inf))
 				 goto err;
 			len = p - cont;
 			}
@@ -1053,12 +1054,66 @@ int asn1_ex_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
 	return ret;
 	}
 
+
+/* This function finds the end of an ASN1 structure when passed its maximum
+ * length, whether it is indefinite length and a pointer to the content.
+ * This is more efficient than calling asn1_collect because it does not
+ * recurse on each indefinite length header.
+ */
+
+static int asn1_find_end(const unsigned char **in, long len, char inf)
+	{
+	int expected_eoc;
+	long plen;
+	const unsigned char *p = *in, *q;
+	/* If not indefinite length constructed just add length */
+	if (inf == 0)
+		{
+		*in += len;
+		return 1;
+		}
+	expected_eoc = 1;
+	/* Indefinite length constructed form. Find the end when enough EOCs
+	 * are found. If more indefinite length constructed headers
+	 * are encountered increment the expected eoc count otherwise just
+	 * skip to the end of the data.
+	 */
+	while (len > 0)
+		{
+		if(asn1_check_eoc(&p, len))
+			{
+			expected_eoc--;
+			if (expected_eoc == 0)
+				break;
+			len -= 2;
+			continue;
+			}
+		q = p;
+		/* Just read in a header: only care about the length */
+		if(!asn1_check_tlen(&plen, NULL, NULL, &inf, NULL, &p, len,
+				-1, 0, 0, NULL))
+			{
+			ASN1err(ASN1_F_ASN1_FIND_END, ERR_R_NESTED_ASN1_ERROR);
+			return 0;
+			}
+		if (inf)
+			expected_eoc++;
+		else
+			p += plen;
+		len -= p - q;
+		}
+	if (expected_eoc)
+		{
+		ASN1err(ASN1_F_ASN1_FIND_END, ASN1_R_MISSING_EOC);
+		return 0;
+		}
+	*in = p;
+	return 1;
+	}
 /* This function collects the asn1 data from a constructred string
  * type into a buffer. The values of 'in' and 'len' should refer
  * to the contents of the constructed type and 'inf' should be set
- * if it is indefinite length. If 'buf' is NULL then we just want
- * to find the end of the current structure: useful for indefinite
- * length constructed stuff.
+ * if it is indefinite length.
  */
 
 static int asn1_collect(BUF_MEM *buf, const unsigned char **in, long len,