[PATCH] Fix ppp_deflate issues with recent zlib_inflate changes

[PATCH] Fix ppp_deflate issues with recent zlib_inflate changes

[Richard Purdie]

The last zlib_inflate update broke certain corner cases for ppp_deflate
decompression handling. This patch fixes some logic to make things work
properly again. Users other than ppp_deflate (the only Z_PACKET_FLUSH
user) should be unaffected.

Fixes bug 8405 (confirmed by the reporter).

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

Index: linux/lib/zlib_inflate/inflate.c
===================================================================
--- linux.orig/lib/zlib_inflate/inflate.c	2007-05-03 23:08:27.000000000 +0100
+++ linux/lib/zlib_inflate/inflate.c	2007-05-03 23:09:39.000000000 +0100
@@ -743,12 +743,14 @@ int zlib_inflate(z_streamp strm, int flu
 
     strm->data_type = state->bits + (state->last ? 64 : 0) +
                       (state->mode == TYPE ? 128 : 0);
-    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
-        ret = Z_BUF_ERROR;
 
     if (flush == Z_PACKET_FLUSH && ret == Z_OK &&
-            (strm->avail_out != 0 || strm->avail_in == 0))
+            strm->avail_out != 0 && strm->avail_in == 0)
 		return zlib_inflateSyncPacket(strm);
+
+    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
+        ret = Z_BUF_ERROR;
+
     return ret;
 }
 

Re: [PATCH] Fix ppp_deflate issues with recent zlib_inflate changes

[Andrew Morton]

On Thu, 03 May 2007 23:18:09 +0100
Richard Purdie <rpurdie@rpsys.net> wrote:

> The last zlib_inflate update broke certain corner cases for ppp_deflate
> decompression handling. This patch fixes some logic to make things work
> properly again. Users other than ppp_deflate (the only Z_PACKET_FLUSH
> user) should be unaffected.
> 
> Fixes bug 8405 (confirmed by the reporter).
> 
> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
> 
> Index: linux/lib/zlib_inflate/inflate.c
> ===================================================================
> --- linux.orig/lib/zlib_inflate/inflate.c	2007-05-03 23:08:27.000000000 +0100
> +++ linux/lib/zlib_inflate/inflate.c	2007-05-03 23:09:39.000000000 +0100
> @@ -743,12 +743,14 @@ int zlib_inflate(z_streamp strm, int flu
>  
>      strm->data_type = state->bits + (state->last ? 64 : 0) +
>                        (state->mode == TYPE ? 128 : 0);
> -    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
> -        ret = Z_BUF_ERROR;
>  
>      if (flush == Z_PACKET_FLUSH && ret == Z_OK &&
> -            (strm->avail_out != 0 || strm->avail_in == 0))
> +            strm->avail_out != 0 && strm->avail_in == 0)
>  		return zlib_inflateSyncPacket(strm);
> +
> +    if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
> +        ret = Z_BUF_ERROR;
> +
>      return ret;
>  }
>  

Thanks heaps, guys.  It was a tough one.  I'll tag it for 2.6.21.x too.