Harden ASN.1 BIO handling of large amounts of data.

[openssl.git] / crypto / asn1 / a_d2i_fp.c

diff --git a/crypto/asn1/a_d2i_fp.c b/crypto/asn1/a_d2i_fp.c
index c0d9e1e68fc791989eaf901ea04acfe58682cad6..b030bf24dc00314b44582df3b4334a2a2503206e 100644 (file)
--- a/crypto/asn1/a_d2i_fp.c
+++ b/crypto/asn1/a_d2i_fp.c
@@ -1,4 +1,3 @@
-/* crypto/asn1/a_d2i_fp.c */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -58,7 +57,7 @@
 
 #include <stdio.h>
 #include <limits.h>
-#include "cryptlib.h"
+#include "internal/cryptlib.h"
 #include <openssl/buffer.h>
 #include <openssl/asn1.h>
 
@@ -97,8 +96,7 @@ void *ASN1_d2i_bio(void *(*xnew) (void), d2i_of_void *d2i, BIO *in, void **x)
     p = (unsigned char *)b->data;
     ret = d2i(x, &p, len);
  err:
-    if (b != NULL)
-        BUF_MEM_free(b);
+    BUF_MEM_free(b);
     return (ret);
 }
 
@@ -118,8 +116,7 @@ void *ASN1_item_d2i_bio(const ASN1_ITEM *it, BIO *in, void *x)
     p = (const unsigned char *)b->data;
     ret = ASN1_item_d2i(x, &p, len, it);
  err:
-    if (b != NULL)
-        BUF_MEM_free(b);
+    BUF_MEM_free(b);
     return (ret);
 }
 
@@ -141,17 +138,21 @@ void *ASN1_item_d2i_fp(const ASN1_ITEM *it, FILE *in, void *x)
 #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;
     unsigned char *p;
     int i;
-    ASN1_const_CTX c;
     size_t want = HEADER_SIZE;
     int eos = 0;
     size_t off = 0;
     size_t len = 0;
 
+    const unsigned char *q;
+    long slen;
+    int inf, tag, xclass;
+
     b = BUF_MEM_new();
     if (b == NULL) {
         ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ERR_R_MALLOC_FAILURE);
@@ -183,10 +184,9 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
         /* else data already loaded */
 
         p = (unsigned char *)&(b->data[off]);
-        c.p = p;
-        c.inf = ASN1_get_object(&(c.p), &(c.slen), &(c.tag), &(c.xclass),
-                                len - off);
-        if (c.inf & 0x80) {
+        q = p;
+        inf = ASN1_get_object(&q, &slen, &tag, &xclass, len - off);
+        if (inf & 0x80) {
             unsigned long e;
 
             e = ERR_GET_REASON(ERR_peek_error());
@@ -195,10 +195,10 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
             else
                 ERR_clear_error(); /* clear error */
         }
-        i = c.p - p;            /* header length */
+        i = q - p;            /* header length */
         off += i;               /* end of data */
 
-        if (c.inf & 1) {
+        if (inf & 1) {
             /* no data body so go round again */
             eos++;
             if (eos < 0) {
@@ -206,7 +206,7 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                 goto err;
             }
             want = HEADER_SIZE;
-        } else if (eos && (c.slen == 0) && (c.tag == V_ASN1_EOC)) {
+        } else if (eos && (slen == 0) && (tag == V_ASN1_EOC)) {
             /* eos value, so go back and read another header */
             eos--;
             if (eos <= 0)
@@ -214,39 +214,54 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
             else
                 want = HEADER_SIZE;
         } else {
-            /* suck in c.slen bytes of data */
-            want = c.slen;
+            /* suck in slen bytes of data */
+            want = 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;
+                        len += i;
+                        chunk -= i;
+                    }
+                    if (chunk_max < INT_MAX/2)
+                        chunk_max *= 2;
                 }
             }
-            if (off + c.slen < off) {
+            if (off + slen < off) {
                 ASN1err(ASN1_F_ASN1_D2I_READ_BIO, ASN1_R_TOO_LONG);
                 goto err;
             }
-            off += c.slen;
+            off += slen;
             if (eos <= 0) {
                 break;
             } else
@@ -262,7 +277,6 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
     *pb = b;
     return off;
  err:
-    if (b != NULL)
-        BUF_MEM_free(b);
+    BUF_MEM_free(b);
     return -1;
 }