| 1 | From b1af4315d823a2b6659c5b14bc17f7bc61878ef4 Mon Sep 17 00:00:00 2001 |
| 2 | From: Phillip Lougher <phillip@lougher.demon.co.uk> |
| 3 | Date: Thu, 6 Aug 2009 15:09:31 -0700 |
| 4 | Subject: [PATCH] bzip2/lzma: remove nasty uncompressed size hack in pre-boot environment |
| 5 | |
| 6 | decompress_bunzip2 and decompress_unlzma have a nasty hack that subtracts |
| 7 | 4 from the input length if being called in the pre-boot environment. |
| 8 | |
| 9 | This is a nasty hack because it relies on the fact that flush = NULL only |
| 10 | when called from the pre-boot environment (i.e. |
| 11 | arch/x86/boot/compressed/misc.c). initramfs.c/do_mounts_rd.c pass in a |
| 12 | flush buffer (flush != NULL). |
| 13 | |
| 14 | This hack prevents the decompressors from being used with flush = NULL by |
| 15 | other callers unless knowledge of the hack is propagated to them. |
| 16 | |
| 17 | This patch removes the hack by making decompress (called only from the |
| 18 | pre-boot environment) a wrapper function that subtracts 4 from the input |
| 19 | length before calling the decompressor. |
| 20 | |
| 21 | Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> |
| 22 | Cc: "H. Peter Anvin" <hpa@zytor.com> |
| 23 | Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| 24 | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| 25 | --- |
| 26 | lib/decompress_bunzip2.c | 22 ++++++++++++++++------ |
| 27 | lib/decompress_unlzma.c | 21 ++++++++++++++++----- |
| 28 | 2 files changed, 32 insertions(+), 11 deletions(-) |
| 29 | |
| 30 | --- a/lib/decompress_bunzip2.c |
| 31 | +++ b/lib/decompress_bunzip2.c |
| 32 | @@ -45,9 +45,11 @@ |
| 33 | */ |
| 34 | |
| 35 | |
| 36 | -#ifndef STATIC |
| 37 | +#ifdef STATIC |
| 38 | +#define PREBOOT |
| 39 | +#else |
| 40 | #include <linux/decompress/bunzip2.h> |
| 41 | -#endif /* !STATIC */ |
| 42 | +#endif /* STATIC */ |
| 43 | |
| 44 | #include <linux/decompress/mm.h> |
| 45 | #include <linux/slab.h> |
| 46 | @@ -681,9 +683,7 @@ STATIC int INIT bunzip2(unsigned char *b |
| 47 | set_error_fn(error_fn); |
| 48 | if (flush) |
| 49 | outbuf = malloc(BZIP2_IOBUF_SIZE); |
| 50 | - else |
| 51 | - len -= 4; /* Uncompressed size hack active in pre-boot |
| 52 | - environment */ |
| 53 | + |
| 54 | if (!outbuf) { |
| 55 | error("Could not allocate output bufer"); |
| 56 | return -1; |
| 57 | @@ -733,4 +733,14 @@ exit_0: |
| 58 | return i; |
| 59 | } |
| 60 | |
| 61 | -#define decompress bunzip2 |
| 62 | +#ifdef PREBOOT |
| 63 | +STATIC int INIT decompress(unsigned char *buf, int len, |
| 64 | + int(*fill)(void*, unsigned int), |
| 65 | + int(*flush)(void*, unsigned int), |
| 66 | + unsigned char *outbuf, |
| 67 | + int *pos, |
| 68 | + void(*error_fn)(char *x)) |
| 69 | +{ |
| 70 | + return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error_fn); |
| 71 | +} |
| 72 | +#endif |
| 73 | --- a/lib/decompress_unlzma.c |
| 74 | +++ b/lib/decompress_unlzma.c |
| 75 | @@ -29,7 +29,9 @@ |
| 76 | *Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 77 | */ |
| 78 | |
| 79 | -#ifndef STATIC |
| 80 | +#ifdef STATIC |
| 81 | +#define PREBOOT |
| 82 | +#else |
| 83 | #include <linux/decompress/unlzma.h> |
| 84 | #endif /* STATIC */ |
| 85 | |
| 86 | @@ -543,9 +545,7 @@ STATIC inline int INIT unlzma(unsigned c |
| 87 | int ret = -1; |
| 88 | |
| 89 | set_error_fn(error_fn); |
| 90 | - if (!flush) |
| 91 | - in_len -= 4; /* Uncompressed size hack active in pre-boot |
| 92 | - environment */ |
| 93 | + |
| 94 | if (buf) |
| 95 | inbuf = buf; |
| 96 | else |
| 97 | @@ -645,4 +645,15 @@ exit_0: |
| 98 | return ret; |
| 99 | } |
| 100 | |
| 101 | -#define decompress unlzma |
| 102 | +#ifdef PREBOOT |
| 103 | +STATIC int INIT decompress(unsigned char *buf, int in_len, |
| 104 | + int(*fill)(void*, unsigned int), |
| 105 | + int(*flush)(void*, unsigned int), |
| 106 | + unsigned char *output, |
| 107 | + int *posp, |
| 108 | + void(*error_fn)(char *x) |
| 109 | + ) |
| 110 | +{ |
| 111 | + return unlzma(buf, in_len - 4, fill, flush, output, posp, error_fn); |
| 112 | +} |
| 113 | +#endif |
| 114 | |
