File openssl-CVE-2016-2109.patch of Package compat-openssl098.11471
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-0.9.8j/crypto/asn1/a_d2i_fp.c
===================================================================
--- openssl-0.9.8j.orig/crypto/asn1/a_d2i_fp.c 2016-04-29 13:11:45.220649768 +0200
+++ openssl-0.9.8j/crypto/asn1/a_d2i_fp.c 2016-04-29 13:11:45.626656035 +0200
@@ -139,6 +139,7 @@ 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;
@@ -230,6 +231,7 @@ static int asn1_d2i_read_bio(BIO *in, BU
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)
@@ -237,24 +239,35 @@ static int asn1_d2i_read_bio(BIO *in, BU
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)
