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Decompressors: fix callback-to-callback mode in decompress_unlzo.c 

Callback-to-callback decompression mode is used for initrd (not
initramfs).  The LZO wrapper is broken for this use case for two reasons:

  - The argument validation is needlessly too strict by
    requiring that "posp" is non-NULL when "fill" is non-NULL.

  - The buffer handling code didn't work at all for this
    use case.

I tested with LZO-compressed kernel, initramfs, initrd, and corrupt
(truncated) initramfs and initrd images.

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Alain Knaff <alain@knaff.lu>
Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Cc: Phillip Lougher <phillip@lougher.demon.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lasse Collin 2011-01-12 17:01:21 -08:00 committed by Linus Torvalds
parent 5a3f81a702
commit fb7fa589fd
1 changed files with 50 additions and 10 deletions
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60
lib/decompress_unlzo.c
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@ -139,8 +139,8 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
goto exit_1;
} else if (input) {
in_buf = input;
} else if (!fill || !posp) {
error("NULL input pointer and missing position pointer or fill function");
} else if (!fill) {
error("NULL input pointer and missing fill function");
goto exit_1;
} else {
in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
@ -154,21 +154,40 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
if (posp)
*posp = 0;
if (fill)
fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
if (fill) {
/*
* Start from in_buf + HEADER_SIZE_MAX to make it possible
* to use memcpy() to copy the unused data to the beginning
* of the buffer. This way memmove() isn't needed which
* is missing from pre-boot environments of most archs.
*/
in_buf += HEADER_SIZE_MAX;
in_len = fill(in_buf, HEADER_SIZE_MAX);
}
if (!parse_header(input, &skip, in_len)) {
if (!parse_header(in_buf, &skip, in_len)) {
error("invalid header");
goto exit_2;
}
in_buf += skip;
in_len -= skip;
if (fill) {
/* Move the unused data to the beginning of the buffer. */
memcpy(in_buf_save, in_buf, in_len);
in_buf = in_buf_save;
}
if (posp)
*posp = skip;
for (;;) {
/* read uncompressed block size */
if (fill && in_len < 4) {
skip = fill(in_buf + in_len, 4 - in_len);
if (skip > 0)
in_len += skip;
}
if (in_len < 4) {
error("file corrupted");
goto exit_2;
@ -190,6 +209,11 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
}
/* read compressed block size, and skip block checksum info */
if (fill && in_len < 8) {
skip = fill(in_buf + in_len, 8 - in_len);
if (skip > 0)
in_len += skip;
}
if (in_len < 8) {
error("file corrupted");
goto exit_2;
@ -198,12 +222,21 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
in_buf += 8;
in_len -= 8;
if (src_len <= 0 || src_len > dst_len || src_len > in_len) {
if (src_len <= 0 || src_len > dst_len) {
error("file corrupted");
goto exit_2;
}
/* decompress */
if (fill && in_len < src_len) {
skip = fill(in_buf + in_len, src_len - in_len);
if (skip > 0)
in_len += skip;
}
if (in_len < src_len) {
error("file corrupted");
goto exit_2;
}
tmp = dst_len;
/* When the input data is not compressed at all,
@ -227,12 +260,19 @@ STATIC inline int INIT unlzo(u8 *input, int in_len,
out_buf += dst_len;
if (posp)
*posp += src_len + 12;
in_buf += src_len;
in_len -= src_len;
if (fill) {
/*
* If there happens to still be unused data left in
* in_buf, move it to the beginning of the buffer.
* Use a loop to avoid memmove() dependency.
*/
if (in_len > 0)
for (skip = 0; skip < in_len; ++skip)
in_buf_save[skip] = in_buf[skip];
in_buf = in_buf_save;
fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE));
} else {
in_buf += src_len;
in_len -= src_len;
}
}