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authorPhillip Lougher <phillip@lougher.demon.co.uk>2009-08-06 15:09:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-07 10:39:56 -0700
commitb1af4315d823a2b6659c5b14bc17f7bc61878ef4 (patch)
treed9a04709f52c27f59a93875fd705dbed2c581b09 /lib/decompress_unlzma.c
parentdaeb6b6fbe27049f465c48a7d0ee5555c3b84064 (diff)
downloadlinux-b1af4315d823a2b6659c5b14bc17f7bc61878ef4.tar.gz
bzip2/lzma: remove nasty uncompressed size hack in pre-boot environment
decompress_bunzip2 and decompress_unlzma have a nasty hack that subtracts
4 from the input length if being called in the pre-boot environment.

This is a nasty hack because it relies on the fact that flush = NULL only
when called from the pre-boot environment (i.e.
arch/x86/boot/compressed/misc.c).  initramfs.c/do_mounts_rd.c pass in a
flush buffer (flush != NULL).

This hack prevents the decompressors from being used with flush = NULL by
other callers unless knowledge of the hack is propagated to them.

This patch removes the hack by making decompress (called only from the
pre-boot environment) a wrapper function that subtracts 4 from the input
length before calling the decompressor.

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/decompress_unlzma.c')
-rw-r--r--lib/decompress_unlzma.c21
1 files changed, 16 insertions, 5 deletions
diff --git a/lib/decompress_unlzma.c b/lib/decompress_unlzma.c
index 32123a1340e6..d3f9468e49dc 100644
--- a/lib/decompress_unlzma.c
+++ b/lib/decompress_unlzma.c
@@ -29,7 +29,9 @@
  *Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
-#ifndef STATIC
+#ifdef STATIC
+#define PREBOOT
+#else
 #include <linux/decompress/unlzma.h>
 #endif /* STATIC */
 
@@ -543,9 +545,7 @@ STATIC inline int INIT unlzma(unsigned char *buf, int in_len,
 	int ret = -1;
 
 	set_error_fn(error_fn);
-	if (!flush)
-		in_len -= 4; /* Uncompressed size hack active in pre-boot
-				environment */
+
 	if (buf)
 		inbuf = buf;
 	else
@@ -645,4 +645,15 @@ exit_0:
 	return ret;
 }
 
-#define decompress unlzma
+#ifdef PREBOOT
+STATIC int INIT decompress(unsigned char *buf, int in_len,
+			      int(*fill)(void*, unsigned int),
+			      int(*flush)(void*, unsigned int),
+			      unsigned char *output,
+			      int *posp,
+			      void(*error_fn)(char *x)
+	)
+{
+	return unlzma(buf, in_len - 4, fill, flush, output, posp, error_fn);
+}
+#endif