From b1af4315d823a2b6659c5b14bc17f7bc61878ef4 Mon Sep 17 00:00:00 2001 From: Phillip Lougher <phillip@lougher.demon.co.uk> Date: Thu, 6 Aug 2009 15:09:31 -0700 Subject: [PATCH] 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> --- lib/decompress_bunzip2.c | 22 ++++++++++++++++------ lib/decompress_unlzma.c | 21 ++++++++++++++++----- 2 files changed, 32 insertions(+), 11 deletions(-) --- a/lib/decompress_bunzip2.c +++ b/lib/decompress_bunzip2.c @@ -45,9 +45,11 @@ */ -#ifndef STATIC +#ifdef STATIC +#define PREBOOT +#else #include <linux/decompress/bunzip2.h> -#endif /* !STATIC */ +#endif /* STATIC */ #include <linux/decompress/mm.h> #include <linux/slab.h> @@ -681,9 +683,7 @@ STATIC int INIT bunzip2(unsigned char *b set_error_fn(error_fn); if (flush) outbuf = malloc(BZIP2_IOBUF_SIZE); - else - len -= 4; /* Uncompressed size hack active in pre-boot - environment */ + if (!outbuf) { error("Could not allocate output bufer"); return -1; @@ -733,4 +733,14 @@ exit_0: return i; } -#define decompress bunzip2 +#ifdef PREBOOT +STATIC int INIT decompress(unsigned char *buf, int len, + int(*fill)(void*, unsigned int), + int(*flush)(void*, unsigned int), + unsigned char *outbuf, + int *pos, + void(*error_fn)(char *x)) +{ + return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error_fn); +} +#endif --- 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 c 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