CVE 2016-2109 fix
Read ASN.1 data in chunks to prevent invalid inputs from allocating
excessive amounts of data.
Bug: 35443725
Test: run cts -m CtsLibcoreTestCases
Test: manually ran testcase from OpenSSL
Change-Id: Ia9d6aa40726c0cba26e2060108112f33e00e8270
Merged-In: Ie00536d7ad815464b2b031f7bcd1b683e12c1623
Merged-In: If087a69ee075b3c5323abb8d7d740e92bd703bb1
Merged-In: If77e23607fc77f724f50ad0e0b94eef4beae57ea
Merged-In: Ia8d0370ece1d5c1750a4331810c610ed5c813224
Merged-In: Ia945d5ce50335919b0783fe909892703213454ef
(cherry picked from commit ea156ae109eac7b7cf7d4f6a76f3c4590734789b)
diff --git a/src/crypto/asn1/a_d2i_fp.c b/src/crypto/asn1/a_d2i_fp.c
index 97ec75b..af03bc0 100644
--- a/src/crypto/asn1/a_d2i_fp.c
+++ b/src/crypto/asn1/a_d2i_fp.c
@@ -140,6 +140,7 @@
#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;
@@ -231,6 +232,7 @@
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)
@@ -238,23 +240,37 @@
OPENSSL_PUT_ERROR(ASN1, ASN1_R_TOO_LONG);
goto err;
}
- if (!BUF_MEM_grow_clean(b,len+want))
- {
- OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
- goto err;
- }
while (want > 0)
{
- i=BIO_read(in,&(b->data[len]),want);
- if (i <= 0)
- {
- OPENSSL_PUT_ERROR(ASN1, ASN1_R_NOT_ENOUGH_DATA);
- goto err;
- }
- /* This can't overflow because
- * |len+want| didn't overflow. */
- len+=i;
- want-=i;
+
+ /*
+ * 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)) {
+ OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
+ goto err;
+ }
+ want -= chunk;
+ while (chunk > 0) {
+ i = BIO_read(in, &(b->data[len]), chunk);
+ if (i <= 0) {
+ OPENSSL_PUT_ERROR(ASN1, ASN1_R_NOT_ENOUGH_DATA);
+ goto err;
+ }
+ /*
+ * This can't overflow because |len+want| didn't
+ * overflow.
+ */
+ len += i;
+ chunk -= i;
+ }
+ if (chunk_max < INT_MAX/2)
+ chunk_max *= 2;
}
}
if (off + c.slen < off)
