Check for potentially exploitable overflows in asn1_d2i_read_bio
[openssl.git] / crypto / asn1 / a_d2i_fp.c
index ece40bc4c0033ba075178c8548d2c56ccf2819eb..52b2ebdb631b9941123eb605cdc6564ed32c8739 100644 (file)
@@ -57,6 +57,7 @@
  */
 
 #include <stdio.h>
+#include <limits.h>
 #include "cryptlib.h"
 #include <openssl/buffer.h>
 #include <openssl/asn1_mac.h>
@@ -143,17 +144,11 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
        BUF_MEM *b;
        unsigned char *p;
        int i;
-       int ret=-1;
        ASN1_const_CTX c;
-       int want=HEADER_SIZE;
+       size_t want=HEADER_SIZE;
        int eos=0;
-#if defined(__GNUC__) && defined(__ia64)
-       /* pathetic compiler bug in all known versions as of Nov. 2002 */
-       long off=0;
-#else
-       int off=0;
-#endif
-       int len=0;
+       size_t off=0;
+       size_t len=0;
 
        b=BUF_MEM_new();
        if (b == NULL)
@@ -169,7 +164,7 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                        {
                        want-=(len-off);
 
-                       if (!BUF_MEM_grow_clean(b,len+want))
+                       if (len + want < len || !BUF_MEM_grow_clean(b,len+want))
                                {
                                ASN1err(ASN1_F_ASN1_D2I_READ_BIO,ERR_R_MALLOC_FAILURE);
                                goto err;
@@ -181,7 +176,14 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                                goto err;
                                }
                        if (i > 0)
+                               {
+                               if (len+i < len)
+                                       {
+                                       ASN1err(ASN1_F_ASN1_D2I_READ_BIO,ASN1_R_TOO_LONG);
+                                       goto err;
+                                       }
                                len+=i;
+                               }
                        }
                /* else data already loaded */
 
@@ -206,6 +208,11 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                        {
                        /* no data body so go round again */
                        eos++;
+                       if (eos < 0)
+                               {
+                               ASN1err(ASN1_F_ASN1_D2I_READ_BIO,ASN1_R_HEADER_TOO_LONG);
+                               goto err;
+                               }
                        want=HEADER_SIZE;
                        }
                else if (eos && (c.slen == 0) && (c.tag == V_ASN1_EOC))
@@ -220,10 +227,16 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                else 
                        {
                        /* suck in c.slen bytes of data */
-                       want=(int)c.slen;
+                       want=c.slen;
                        if (want > (len-off))
                                {
                                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);
@@ -238,11 +251,18 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                                                    ASN1_R_NOT_ENOUGH_DATA);
                                                goto err;
                                                }
+                                       /* This can't overflow because
+                                        * |len+want| didn't overflow. */
                                        len+=i;
-                                       want -= i;
+                                       want-=i;
                                        }
                                }
-                       off+=(int)c.slen;
+                       if (off + c.slen < off)
+                               {
+                               ASN1err(ASN1_F_ASN1_D2I_READ_BIO,ASN1_R_TOO_LONG);
+                               goto err;
+                               }
+                       off+=c.slen;
                        if (eos <= 0)
                                {
                                break;
@@ -252,9 +272,15 @@ static int asn1_d2i_read_bio(BIO *in, BUF_MEM **pb)
                        }
                }
 
+       if (off > INT_MAX)
+               {
+               ASN1err(ASN1_F_ASN1_D2I_READ_BIO,ASN1_R_TOO_LONG);
+               goto err;
+               }
+
        *pb = b;
        return off;
 err:
        if (b != NULL) BUF_MEM_free(b);
-       return(ret);
+       return -1;
        }