Fix integer overflow in ASN.1 parsing functions.
Bug: 6274291
Change-Id: Id0850ce39aebfc9018c0459ec3147e05506a646f
diff --git a/crypto/buffer/buffer.c b/crypto/buffer/buffer.c
index f4b358b..52e65df 100644
--- a/crypto/buffer/buffer.c
+++ b/crypto/buffer/buffer.c
@@ -60,6 +60,11 @@
#include "cryptlib.h"
#include <openssl/buffer.h>
+/* LIMIT_BEFORE_EXPANSION is the maximum n such that (n+3)/3*4 < 2**31. That
+ * function is applied in several functions in this file and this limit ensures
+ * that the result fits in an int. */
+#define LIMIT_BEFORE_EXPANSION 0x5ffffffc
+
BUF_MEM *BUF_MEM_new(void)
{
BUF_MEM *ret;
@@ -105,6 +110,12 @@
str->length=len;
return(len);
}
+ /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
+ if (len > LIMIT_BEFORE_EXPANSION)
+ {
+ BUFerr(BUF_F_BUF_MEM_GROW,ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
n=(len+3)/3*4;
if (str->data == NULL)
ret=OPENSSL_malloc(n);
@@ -142,6 +153,12 @@
str->length=len;
return(len);
}
+ /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
+ if (len > LIMIT_BEFORE_EXPANSION)
+ {
+ BUFerr(BUF_F_BUF_MEM_GROW,ERR_R_MALLOC_FAILURE);
+ return 0;
+ }
n=(len+3)/3*4;
if (str->data == NULL)
ret=OPENSSL_malloc(n);