[Xen-devel] [PATCH] xc_inflate_buffer fix

[David Lively <dlively@xxxxxxxxxxxxxxx>]

Hi -
  I notice some of my initrds are failing to gunzip:
ERROR: inflate failed, sts -5
  These same initrds work fine with Ben Thomas' original
patch introducing xc_{linux,hvm}_build_mem.  The checked-in
version changed some declarations from unsigned char * to
char *, breaking the output length computation in xc_inflate_buffer.
  This patch assumes you want to keep using the signed char *
for the interface, so it simply inserts a few casts to unsigned.
Tested lightly, but the bug is pretty obvious once you notice
the signedness change ...

Dave

diff -r 1d741a415927 tools/libxc/xg_private.c
--- a/tools/libxc/xg_private.c  Wed Mar 15 11:48:33 2006 -0500
+++ b/tools/libxc/xg_private.c  Wed Mar 15 12:28:05 2006 -0500
@@ -77,10 +77,11 @@ char *xc_inflate_buffer(const char *in_b
         return (char *)in_buf;
     }
 
-    out_len = in_buf[in_size-4] +
-        (256 * (in_buf[in_size-3] +
-                (256 * (in_buf[in_size-2] +
-                        (256 * in_buf[in_size-1])))));
+    out_len = (unsigned char)in_buf[in_size-4] +
+        (256 * ((unsigned char)in_buf[in_size-3] +
+                (256 * ((unsigned char)in_buf[in_size-2] +
+                        (256 * (unsigned char)in_buf[in_size-1])))));
+
     bzero(&zStream, sizeof(zStream));
     out_buf = malloc(out_len + 16);        /* Leave a little extra space */
     if ( out_buf == NULL )

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