4963bb2b89
- Add unzstd() and the zstd decompress interface. - Add zstd support to decompress_method(). The decompress_method() and unzstd() functions are used to decompress the initramfs and the initrd. The __decompress() function is used in the preboot environment to decompress a zstd compressed kernel. The zstd decompression function allows the input and output buffers to overlap because that is used by x86 kernel decompression. Signed-off-by: Nick Terrell <terrelln@fb.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200730190841.2071656-3-nickrterrell@gmail.com
85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* decompress.c
|
|
*
|
|
* Detect the decompression method based on magic number
|
|
*/
|
|
|
|
#include <linux/decompress/generic.h>
|
|
|
|
#include <linux/decompress/bunzip2.h>
|
|
#include <linux/decompress/unlzma.h>
|
|
#include <linux/decompress/unxz.h>
|
|
#include <linux/decompress/inflate.h>
|
|
#include <linux/decompress/unlzo.h>
|
|
#include <linux/decompress/unlz4.h>
|
|
#include <linux/decompress/unzstd.h>
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/string.h>
|
|
#include <linux/init.h>
|
|
#include <linux/printk.h>
|
|
|
|
#ifndef CONFIG_DECOMPRESS_GZIP
|
|
# define gunzip NULL
|
|
#endif
|
|
#ifndef CONFIG_DECOMPRESS_BZIP2
|
|
# define bunzip2 NULL
|
|
#endif
|
|
#ifndef CONFIG_DECOMPRESS_LZMA
|
|
# define unlzma NULL
|
|
#endif
|
|
#ifndef CONFIG_DECOMPRESS_XZ
|
|
# define unxz NULL
|
|
#endif
|
|
#ifndef CONFIG_DECOMPRESS_LZO
|
|
# define unlzo NULL
|
|
#endif
|
|
#ifndef CONFIG_DECOMPRESS_LZ4
|
|
# define unlz4 NULL
|
|
#endif
|
|
#ifndef CONFIG_DECOMPRESS_ZSTD
|
|
# define unzstd NULL
|
|
#endif
|
|
|
|
struct compress_format {
|
|
unsigned char magic[2];
|
|
const char *name;
|
|
decompress_fn decompressor;
|
|
};
|
|
|
|
static const struct compress_format compressed_formats[] __initconst = {
|
|
{ {0x1f, 0x8b}, "gzip", gunzip },
|
|
{ {0x1f, 0x9e}, "gzip", gunzip },
|
|
{ {0x42, 0x5a}, "bzip2", bunzip2 },
|
|
{ {0x5d, 0x00}, "lzma", unlzma },
|
|
{ {0xfd, 0x37}, "xz", unxz },
|
|
{ {0x89, 0x4c}, "lzo", unlzo },
|
|
{ {0x02, 0x21}, "lz4", unlz4 },
|
|
{ {0x28, 0xb5}, "zstd", unzstd },
|
|
{ {0, 0}, NULL, NULL }
|
|
};
|
|
|
|
decompress_fn __init decompress_method(const unsigned char *inbuf, long len,
|
|
const char **name)
|
|
{
|
|
const struct compress_format *cf;
|
|
|
|
if (len < 2) {
|
|
if (name)
|
|
*name = NULL;
|
|
return NULL; /* Need at least this much... */
|
|
}
|
|
|
|
pr_debug("Compressed data magic: %#.2x %#.2x\n", inbuf[0], inbuf[1]);
|
|
|
|
for (cf = compressed_formats; cf->name; cf++) {
|
|
if (!memcmp(inbuf, cf->magic, 2))
|
|
break;
|
|
|
|
}
|
|
if (name)
|
|
*name = cf->name;
|
|
return cf->decompressor;
|
|
}
|