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module/decompress: Support zstd in-kernel decompression

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Add support for zstd compressed modules to the in-kernel decompression
code. This allows zstd compressed modules to be decompressed by the
kernel, similar to the existing support for gzip and xz compressed
modules.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Piotr Gorski <lucjan.lucjanov@gmail.com>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Piotr Gorski <lucjan.lucjanov@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This commit is contained in:
Stephen Boyd 2022-12-06 13:53:18 -08:00 committed by Luis Chamberlain
parent c86a514f5f
commit 169a58ad82
2 changed files with 92 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
kernel/module/Kconfig
View file

@ -221,9 +221,10 @@ endchoice
config MODULE_DECOMPRESS
bool "Support in-kernel module decompression"
depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ
depends on MODULE_COMPRESS_GZIP || MODULE_COMPRESS_XZ || MODULE_COMPRESS_ZSTD
select ZLIB_INFLATE if MODULE_COMPRESS_GZIP
select XZ_DEC if MODULE_COMPRESS_XZ
select ZSTD_DECOMPRESS if MODULE_COMPRESS_ZSTD
help
Support for decompressing kernel modules by the kernel itself

92
kernel/module/decompress.c
View file

@ -50,7 +50,7 @@ static struct page *module_get_next_page(struct load_info *info)
return page;
}
#ifdef CONFIG_MODULE_COMPRESS_GZIP
#if defined(CONFIG_MODULE_COMPRESS_GZIP)
#include <linux/zlib.h>
#define MODULE_COMPRESSION gzip
#define MODULE_DECOMPRESS_FN module_gzip_decompress
@ -141,7 +141,7 @@ static ssize_t module_gzip_decompress(struct load_info *info,
kfree(s.workspace);
return retval;
}
#elif CONFIG_MODULE_COMPRESS_XZ
#elif defined(CONFIG_MODULE_COMPRESS_XZ)
#include <linux/xz.h>
#define MODULE_COMPRESSION xz
#define MODULE_DECOMPRESS_FN module_xz_decompress
@ -199,6 +199,94 @@ static ssize_t module_xz_decompress(struct load_info *info,
xz_dec_end(xz_dec);
return retval;
}
#elif defined(CONFIG_MODULE_COMPRESS_ZSTD)
#include <linux/zstd.h>
#define MODULE_COMPRESSION zstd
#define MODULE_DECOMPRESS_FN module_zstd_decompress
static ssize_t module_zstd_decompress(struct load_info *info,
const void *buf, size_t size)
{
static const u8 signature[] = { 0x28, 0xb5, 0x2f, 0xfd };
ZSTD_outBuffer zstd_dec;
ZSTD_inBuffer zstd_buf;
zstd_frame_header header;
size_t wksp_size;
void *wksp = NULL;
ZSTD_DStream *dstream;
size_t ret;
size_t new_size = 0;
int retval;
if (size < sizeof(signature) ||
memcmp(buf, signature, sizeof(signature))) {
pr_err("not a zstd compressed module\n");
return -EINVAL;
}
zstd_buf.src = buf;
zstd_buf.pos = 0;
zstd_buf.size = size;
ret = zstd_get_frame_header(&header, zstd_buf.src, zstd_buf.size);
if (ret != 0) {
pr_err("ZSTD-compressed data has an incomplete frame header\n");
retval = -EINVAL;
goto out;
}
if (header.windowSize > (1 << ZSTD_WINDOWLOG_MAX)) {
pr_err("ZSTD-compressed data has too large a window size\n");
retval = -EINVAL;
goto out;
}
wksp_size = zstd_dstream_workspace_bound(header.windowSize);
wksp = kmalloc(wksp_size, GFP_KERNEL);
if (!wksp) {
retval = -ENOMEM;
goto out;
}
dstream = zstd_init_dstream(header.windowSize, wksp, wksp_size);
if (!dstream) {
pr_err("Can't initialize ZSTD stream\n");
retval = -ENOMEM;
goto out;
}
do {
struct page *page = module_get_next_page(info);
if (!IS_ERR(page)) {
retval = PTR_ERR(page);
goto out;
}
zstd_dec.dst = kmap_local_page(page);
zstd_dec.pos = 0;
zstd_dec.size = PAGE_SIZE;
ret = zstd_decompress_stream(dstream, &zstd_dec, &zstd_buf);
kunmap(page);
retval = zstd_get_error_code(ret);
if (retval)
break;
new_size += zstd_dec.pos;
} while (zstd_dec.pos == PAGE_SIZE && ret != 0);
if (retval) {
pr_err("ZSTD-decompression failed with status %d\n", retval);
retval = -EINVAL;
goto out;
}
retval = new_size;
out:
kfree(wksp);
return retval;
}
#else
#error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS"
#endif