linux-stable/lib/decompress_unlz4.c
Yinghai Lu 2d3862d26e lib/decompressors: use real out buf size for gunzip with kernel
When loading x86 64bit kernel above 4GiB with patched grub2, got kernel
gunzip error.

| early console in decompress_kernel
| decompress_kernel:
|       input: [0x807f2143b4-0x807ff61aee]
|      output: [0x807cc00000-0x807f3ea29b] 0x027ea29c: output_len
| boot via startup_64
| KASLR using RDTSC...
|  new output: [0x46fe000000-0x470138cfff] 0x0338d000: output_run_size
|  decompress: [0x46fe000000-0x47007ea29b] <=== [0x807f2143b4-0x807ff61aee]
|
| Decompressing Linux... gz...
|
| uncompression error
|
| -- System halted

the new buffer is at 0x46fe000000ULL, decompressor_gzip is using
0xffffffb901ffffff as out_len.  gunzip in lib/zlib_inflate/inflate.c cap
that len to 0x01ffffff and decompress fails later.

We could hit this problem with crashkernel booting that uses kexec loading
kernel above 4GiB.

We have decompress_* support:
    1. inbuf[]/outbuf[] for kernel preboot.
    2. inbuf[]/flush() for initramfs
    3. fill()/flush() for initrd.
This bug only affect kernel preboot path that use outbuf[].

Add __decompress and take real out_buf_len for gunzip instead of guessing
wrong buf size.

Fixes: 1431574a1c (lib/decompressors: fix "no limit" output buffer length)
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Jon Medhurst <tixy@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 13:29:01 -07:00

209 lines
4.2 KiB
C

/*
* Wrapper for decompressing LZ4-compressed kernel, initramfs, and initrd
*
* Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifdef STATIC
#define PREBOOT
#include "lz4/lz4_decompress.c"
#else
#include <linux/decompress/unlz4.h>
#endif
#include <linux/types.h>
#include <linux/lz4.h>
#include <linux/decompress/mm.h>
#include <linux/compiler.h>
#include <asm/unaligned.h>
/*
* Note: Uncompressed chunk size is used in the compressor side
* (userspace side for compression).
* It is hardcoded because there is not proper way to extract it
* from the binary stream which is generated by the preliminary
* version of LZ4 tool so far.
*/
#define LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE (8 << 20)
#define ARCHIVE_MAGICNUMBER 0x184C2102
STATIC inline int INIT unlz4(u8 *input, long in_len,
long (*fill)(void *, unsigned long),
long (*flush)(void *, unsigned long),
u8 *output, long *posp,
void (*error) (char *x))
{
int ret = -1;
size_t chunksize = 0;
size_t uncomp_chunksize = LZ4_DEFAULT_UNCOMPRESSED_CHUNK_SIZE;
u8 *inp;
u8 *inp_start;
u8 *outp;
long size = in_len;
#ifdef PREBOOT
size_t out_len = get_unaligned_le32(input + in_len);
#endif
size_t dest_len;
if (output) {
outp = output;
} else if (!flush) {
error("NULL output pointer and no flush function provided");
goto exit_0;
} else {
outp = large_malloc(uncomp_chunksize);
if (!outp) {
error("Could not allocate output buffer");
goto exit_0;
}
}
if (input && fill) {
error("Both input pointer and fill function provided,");
goto exit_1;
} else if (input) {
inp = input;
} else if (!fill) {
error("NULL input pointer and missing fill function");
goto exit_1;
} else {
inp = large_malloc(lz4_compressbound(uncomp_chunksize));
if (!inp) {
error("Could not allocate input buffer");
goto exit_1;
}
}
inp_start = inp;
if (posp)
*posp = 0;
if (fill) {
size = fill(inp, 4);
if (size < 4) {
error("data corrupted");
goto exit_2;
}
}
chunksize = get_unaligned_le32(inp);
if (chunksize == ARCHIVE_MAGICNUMBER) {
if (!fill) {
inp += 4;
size -= 4;
}
} else {
error("invalid header");
goto exit_2;
}
if (posp)
*posp += 4;
for (;;) {
if (fill) {
size = fill(inp, 4);
if (size == 0)
break;
if (size < 4) {
error("data corrupted");
goto exit_2;
}
}
chunksize = get_unaligned_le32(inp);
if (chunksize == ARCHIVE_MAGICNUMBER) {
if (!fill) {
inp += 4;
size -= 4;
}
if (posp)
*posp += 4;
continue;
}
if (posp)
*posp += 4;
if (!fill) {
inp += 4;
size -= 4;
} else {
if (chunksize > lz4_compressbound(uncomp_chunksize)) {
error("chunk length is longer than allocated");
goto exit_2;
}
size = fill(inp, chunksize);
if (size < chunksize) {
error("data corrupted");
goto exit_2;
}
}
#ifdef PREBOOT
if (out_len >= uncomp_chunksize) {
dest_len = uncomp_chunksize;
out_len -= dest_len;
} else
dest_len = out_len;
ret = lz4_decompress(inp, &chunksize, outp, dest_len);
#else
dest_len = uncomp_chunksize;
ret = lz4_decompress_unknownoutputsize(inp, chunksize, outp,
&dest_len);
#endif
if (ret < 0) {
error("Decoding failed");
goto exit_2;
}
ret = -1;
if (flush && flush(outp, dest_len) != dest_len)
goto exit_2;
if (output)
outp += dest_len;
if (posp)
*posp += chunksize;
if (!fill) {
size -= chunksize;
if (size == 0)
break;
else if (size < 0) {
error("data corrupted");
goto exit_2;
}
inp += chunksize;
}
}
ret = 0;
exit_2:
if (!input)
large_free(inp_start);
exit_1:
if (!output)
large_free(outp);
exit_0:
return ret;
}
#ifdef PREBOOT
STATIC int INIT __decompress(unsigned char *buf, long in_len,
long (*fill)(void*, unsigned long),
long (*flush)(void*, unsigned long),
unsigned char *output, long out_len,
long *posp,
void (*error)(char *x)
)
{
return unlz4(buf, in_len - 4, fill, flush, output, posp, error);
}
#endif