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Thread: Re: bug in pgcrypto 0.3

Re: bug in pgcrypto 0.3

From
Marko Kreen
Date:
On Sat, May 12, 2001 at 12:47:33AM -0400, Neil Conway wrote:
> I've been experimenting with pgcrypto 0.3 (distributed with
> Postgres 7.1.0), and I think I've found a bug.
> 
> I compiled Pgcrypto with OpenSSL, using gcc 2.95.4 and
> OpenSSL 0.9.6a (the latest Debian 'unstable' packages).

> web=> select encode(digest('blah', 'sha1'), 'base64');
> FATAL 1:  pg_encode: overflow, encode estimate too small
> pqReadData() -- backend closed the channel unexpectedly.
>         This probably means the backend terminated abnormally
>         before or while processing the request.
> The connection to the server was lost. Attempting reset: Succeeded.

> Is this a bug? Can it be fixed?

This is a bug alright.  And a silly one :)

Thanks for reporting.  For standalone package apply this
patch with -p2.

pgsql-hackers: this should get into REL7_1_STABLE.

-- 
marko


Index: contrib/pgcrypto/encode.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/contrib/pgcrypto/encode.c,v
retrieving revision 1.4
diff -u -r1.4 encode.c
--- contrib/pgcrypto/encode.c    2001/03/22 03:59:10    1.4
+++ contrib/pgcrypto/encode.c    2001/05/12 08:28:50
@@ -349,7 +349,7 @@uintb64_enc_len(uint srclen){
-    return srclen + (srclen / 3) + (srclen / (76 / 2));
+    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;}uint

Re: Re: bug in pgcrypto 0.3

From
Bruce Momjian
Date:
Applied to 7.1.X and 7.2.


> On Sat, May 12, 2001 at 12:47:33AM -0400, Neil Conway wrote:
> > I've been experimenting with pgcrypto 0.3 (distributed with
> > Postgres 7.1.0), and I think I've found a bug.
> > 
> > I compiled Pgcrypto with OpenSSL, using gcc 2.95.4 and
> > OpenSSL 0.9.6a (the latest Debian 'unstable' packages).
> 
> > web=> select encode(digest('blah', 'sha1'), 'base64');
> > FATAL 1:  pg_encode: overflow, encode estimate too small
> > pqReadData() -- backend closed the channel unexpectedly.
> >         This probably means the backend terminated abnormally
> >         before or while processing the request.
> > The connection to the server was lost. Attempting reset: Succeeded.
> 
> > Is this a bug? Can it be fixed?
> 
> This is a bug alright.  And a silly one :)
> 
> Thanks for reporting.  For standalone package apply this
> patch with -p2.
> 
> pgsql-hackers: this should get into REL7_1_STABLE.
> 
> -- 
> marko
> 
> 
> Index: contrib/pgcrypto/encode.c
> ===================================================================
> RCS file: /home/projects/pgsql/cvsroot/pgsql/contrib/pgcrypto/encode.c,v
> retrieving revision 1.4
> diff -u -r1.4 encode.c
> --- contrib/pgcrypto/encode.c    2001/03/22 03:59:10    1.4
> +++ contrib/pgcrypto/encode.c    2001/05/12 08:28:50
> @@ -349,7 +349,7 @@
>  uint
>  b64_enc_len(uint srclen)
>  {
> -    return srclen + (srclen / 3) + (srclen / (76 / 2));
> +    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;
>  }
>  
>  uint
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
> 

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026

Re: Re: bug in pgcrypto 0.3

From
Ian Lance Taylor
Date:
Bruce Momjian <pgman@candle.pha.pa.us> writes:

> Applied to 7.1.X and 7.2.

But, but...

> > -    return srclen + (srclen / 3) + (srclen / (76 / 2));
> > +    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;

(srclen + 2 / 3) is always the same as (srclen).

Perhaps this was meant to be ((srclen + 2) / 3)?

The current code is safe, but weird.

Ian

Re: Re: bug in pgcrypto 0.3

From
Marko Kreen
Date:
On Mon, May 14, 2001 at 01:15:59PM -0700, Ian Lance Taylor wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Applied to 7.1.X and 7.2.
> 
> But, but...

;)

> > > -    return srclen + (srclen / 3) + (srclen / (76 / 2));
> > > +    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;
> 
> (srclen + 2 / 3) is always the same as (srclen).
> 
> Perhaps this was meant to be ((srclen + 2) / 3)?

I guess too...  Its no good to create patches half-asleep...

> The current code is safe, but weird.

But I got very good response time :)

Well, the correct code - that corresponds to current
encode - is below.  I even got the linefeed stuff wrong.

-- 
marko



Index: contrib/pgcrypto/encode.c
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/contrib/pgcrypto/encode.c,v
retrieving revision 1.5
diff -u -r1.5 encode.c
--- contrib/pgcrypto/encode.c    2001/05/13 02:17:09    1.5
+++ contrib/pgcrypto/encode.c    2001/05/14 21:29:43
@@ -349,7 +349,8 @@uintb64_enc_len(uint srclen){
-    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;
+    /* 3 bytes will be converted to 4, linefeed after 76 chars */
+    return (srclen + 2) * 4 / 3 + srclen / (76 * 3 / 4);}uint

Re: Re: bug in pgcrypto 0.3

From
Bruce Momjian
Date:
Applied for 7.1.X and 7.2.

> On Mon, May 14, 2001 at 01:15:59PM -0700, Ian Lance Taylor wrote:
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > > Applied to 7.1.X and 7.2.
> > 
> > But, but...
> 
> ;)
> 
> > > > -    return srclen + (srclen / 3) + (srclen / (76 / 2));
> > > > +    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;
> > 
> > (srclen + 2 / 3) is always the same as (srclen).
> > 
> > Perhaps this was meant to be ((srclen + 2) / 3)?
> 
> I guess too...  Its no good to create patches half-asleep...
> 
> > The current code is safe, but weird.
> 
> But I got very good response time :)
> 
> Well, the correct code - that corresponds to current
> encode - is below.  I even got the linefeed stuff wrong.
> 
> -- 
> marko
> 
> 
> 
> Index: contrib/pgcrypto/encode.c
> ===================================================================
> RCS file: /home/projects/pgsql/cvsroot/pgsql/contrib/pgcrypto/encode.c,v
> retrieving revision 1.5
> diff -u -r1.5 encode.c
> --- contrib/pgcrypto/encode.c    2001/05/13 02:17:09    1.5
> +++ contrib/pgcrypto/encode.c    2001/05/14 21:29:43
> @@ -349,7 +349,8 @@
>  uint
>  b64_enc_len(uint srclen)
>  {
> -    return srclen + (srclen + 2 / 3) + (srclen / (76 / 2)) + 2;
> +    /* 3 bytes will be converted to 4, linefeed after 76 chars */
> +    return (srclen + 2) * 4 / 3 + srclen / (76 * 3 / 4);
>  }
>  
>  uint
> 

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
853-3000+  If your life is a hard drive,     |  830 Blythe Avenue +  Christ can be your backup.        |  Drexel Hill,
Pennsylvania19026