File openssl-CVE-2016-2109.patch of Package libopenssl0_9_8

From 3d411057a5e28530fffc40b257698f453c89aa87 Mon Sep 17 00:00:00 2001
From: "Dr. Stephen Henson" <steve@openssl.org>
Date: Mon, 11 Apr 2016 13:57:20 +0100
Subject: [PATCH] Harden ASN.1 BIO handling of large amounts of data.

If the ASN.1 BIO is presented with a large length field read it in
chunks of increasing size checking for EOF on each read. This prevents
small files allocating excessive amounts of data.

CVE-2016-2109

Thanks to Brian Carpenter for reporting this issue.

Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(cherry picked from commit c62981390d6cf9e3d612c489b8b77c2913b25807)
---
 crypto/asn1/a_d2i_fp.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

Index: openssl-0.9.8zh/crypto/asn1/a_d2i_fp.c
===================================================================
--- openssl-0.9.8zh.orig/crypto/asn1/a_d2i_fp.c	2016-05-03 17:33:33.645042837 +0200
+++ openssl-0.9.8zh/crypto/asn1/a_d2i_fp.c	2016-05-03 17:37:05.277361515 +0200
@@ -141,6 +141,7 @@ void *ASN1_item_d2i_fp(const ASN1_ITEM *
 #endif
 
 #define HEADER_SIZE   8
+#define ASN1_CHUNK_INITIAL_SIZE (16 * 1024)
 static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
 {
     BUF_MEM *b;
@@ -217,29 +218,43 @@ static int asn1_d2i_read_bio(BIO *in, BU
             /* suck in c.slen bytes of data */
             want = c.slen;
             if (want > (len - off)) {
+                size_t chunk_max = ASN1_CHUNK_INITIAL_SIZE;
                 want -= (len - off);
                 if (want > INT_MAX /* BIO_read takes an int length */  ||
                     len + want < len) {
                     ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ASN1_R_TOO_LONG);
                     goto err;
                 }
-                if (!BUF_MEM_grow_clean(b, len + want)) {
-                    ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ERR_R_MALLOC_FAILURE);
-                    goto err;
-                }
                 while (want > 0) {
-                    i = BIO_read(in, &(b->data[len]), want);
-                    if (i <= 0) {
-                        ASN1err(ASN1_F_ASN1_D2I_READ_BIO,
-                                ASN1_R_NOT_ENOUGH_DATA);
+		    /*
+		     * Read content in chunks of increasing size
+		     * so we can return an error for EOF without
+		     * having to allocate the entire content length
+		     * in one go.
+		     */
+		    size_t chunk = want > chunk_max ? chunk_max : want;
+
+		    if (!BUF_MEM_grow_clean(b, len + chunk)) {
+			ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ERR_R_MALLOC_FAILURE);
                         goto err;
                     }
+		    want -= chunk;
+		    while (chunk > 0) {
+			i = BIO_read(in, &(b->data[len]), chunk);
+			if (i <= 0) {
+			    ASN1err(ASN1_F_ASN1_D2I_READ_BIO,
+				    ASN1_R_NOT_ENOUGH_DATA);
+			    goto err;
+			}
                     /*
                      * This can't overflow because |len+want| didn't
                      * overflow.
                      */
                     len += i;
-                    want -= i;
+		chunk-=i;
+		}
+	    if (chunk_max < INT_MAX/2)
+		chunk_max *= 2;
                 }
             }
             if (off + c.slen < off) {