Re: [Patch] b64Buf to short for certs with a key length longer than 1024 bits

[Berin Lautenbach]

Done (belatedly).

Thanks!

Cheers,
        Berin

Vadim Ismailov wrote:

Here's another one. OpenSSLCryptoKeyRSA.cpp line 198:

unsigned char sigVal[512];

I was using 4096 bit RSA key and it was corrupting stack during
signature verification. I changed buffer size to 1024 and it works
now. EVP_DecodeUpdate still returns 512 bytes and EVP_DecodeFinal()
returns 0 and probably 513 bytes would be enough, but I like even
numbers. Anyhow, there's a problem there.

Vadim

On Sun, 28 Nov 2004 22:36:20 +1100, Berin Lautenbach
<[EMAIL PROTECTED]> wrote:

Michael,

Thanks for that!  I have just committed to CVS.

Cheers,
      Berin

Michael Braunoeder wrote:

Hi,

I noticed some problems generating XML-signatures with certificates
which have a key longer than 1024 bits. DSIGSignature::sign produced an
signature without an errors, but when I tried to verify the signature I
got an "OpenSSL:RSA::verify() - Error decrypting signature" execption.

The problem was the
char b64Buf[256];
in DSIGSignature::sign. This is to small for longer keys.
The attached patch changes the length to 1024. It works now for keys
with a key length of 2048 and 4096.

kind regards,
Michael

------------------------------------------------------------------------

diff -r -u xml-security-c-1.1.0.orig/src/dsig/DSIGSignature.cpp 
xml-security-c-1.1.0/src/dsig/DSIGSignature.cpp
--- xml-security-c-1.1.0.orig/src/dsig/DSIGSignature.cpp      2004-03-07 
04:20:51.000000000 +0100
+++ xml-security-c-1.1.0/src/dsig/DSIGSignature.cpp   2004-11-16 
12:07:08.000000000 +0100
@@ -1102,7 +1102,7 @@

     // Now check the calculated hash

-     char b64Buf[256];
+     char b64Buf[1024];
     unsigned int b64Len;
     safeBuffer b64SB;

@@ -1122,7 +1122,7 @@
                     hash,
                     hashLen,
                     (char *) b64Buf,
-                     256);
+                     1024);

             if (b64Len <= 0) {

@@ -1152,7 +1152,7 @@
                     hash,
                     hashLen,
                     (char *) b64Buf,
-                     256);
+                     1024);

             if (b64Len <= 0) {

@@ -1186,7 +1186,7 @@
                                                             hashLen,
                                                             
mp_signedInfo->getHMACOutputLength());

-             strncpy(b64Buf, (char *) b64SB.rawBuffer(), 255);
+             strncpy(b64Buf, (char *) b64SB.rawBuffer(), 1024);
             break;

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