Re: [PATCH v2] pstore: add lzo/lz4 compression support
From: Kees Cook
Date: Mon May 02 2016 - 14:36:05 EST
On Fri, Apr 29, 2016 at 7:26 PM, Geliang Tang <geliangtang@xxxxxxx> wrote:
> On Thu, Feb 18, 2016 at 09:37:26AM -0800, Kees Cook wrote:
>> On Thu, Feb 18, 2016 at 6:04 AM, Geliang Tang <geliangtang@xxxxxxx> wrote:
>> > Like zlib compression in pstore, this patch added lzo and lz4
>> > compression support so that users can have more options and better
>> > compression ratio.
>> >
>> > The original code treats the compressed data together with the
>> > uncompressed ECC correction notice by using zlib decompress. The
>> > ECC correction notice is missing in the decompression process. The
>> > treatment also makes lzo and lz4 not working. So I treat them
>> > separately by using pstore_decompress() to treat the compressed
>> > data, and memcpy() to treat the uncompressed ECC correction notice.
>> >
>> > Signed-off-by: Geliang Tang <geliangtang@xxxxxxx>
>>
>> Thanks for the updates!
>>
>> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
>>
>> -Kees
>
> Hi there,
>
> It's been three months since this patch has been reviewed. But it hasn't
> been replied yet by far. Can I please know if there's anything wrong with
> it?
Tony, should I take over the pstore tree? Do you have any testing
procedures I could use? My testing is rather manual at the moment.
-Kees
>
> -Geliang Tang
>
>> > ---
>> > Changes in v2:
>> > revise the patch as Kees suggested:
>> > - drop 'depends on PSTORE' in config choice PSTORE_ZLIB/LZO/LZ4_COMPRESS;
>> > - set big_oops_buf_sz to 0 in free_zlib/lzo/lz4;
>> > - change zbackend[] to zbackend.
>> > ---
>> > drivers/firmware/efi/efi-pstore.c | 1 +
>> > fs/pstore/Kconfig | 31 +++++-
>> > fs/pstore/platform.c | 218 ++++++++++++++++++++++++++++++++++++--
>> > fs/pstore/ram.c | 10 +-
>> > include/linux/pstore.h | 3 +-
>> > 5 files changed, 248 insertions(+), 15 deletions(-)
>> >
>> > diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c
>> > index eac76a7..cd8c35f 100644
>> > --- a/drivers/firmware/efi/efi-pstore.c
>> > +++ b/drivers/firmware/efi/efi-pstore.c
>> > @@ -210,6 +210,7 @@ static int efi_pstore_sysfs_entry_iter(void *data, struct efivar_entry **pos)
>> > static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
>> > int *count, struct timespec *timespec,
>> > char **buf, bool *compressed,
>> > + ssize_t *ecc_notice_size,
>> > struct pstore_info *psi)
>> > {
>> > struct pstore_read_data data;
>> > diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
>> > index 360ae43..be40813 100644
>> > --- a/fs/pstore/Kconfig
>> > +++ b/fs/pstore/Kconfig
>> > @@ -1,8 +1,6 @@
>> > config PSTORE
>> > tristate "Persistent store support"
>> > default n
>> > - select ZLIB_DEFLATE
>> > - select ZLIB_INFLATE
>> > help
>> > This option enables generic access to platform level
>> > persistent storage via "pstore" filesystem that can
>> > @@ -14,6 +12,35 @@ config PSTORE
>> > If you don't have a platform persistent store driver,
>> > say N.
>> >
>> > +choice
>> > + prompt "Choose compression algorithm"
>> > + depends on PSTORE
>> > + default PSTORE_ZLIB_COMPRESS
>> > + help
>> > + This option chooses compression algorithm.
>> > +
>> > +config PSTORE_ZLIB_COMPRESS
>> > + bool "ZLIB"
>> > + select ZLIB_DEFLATE
>> > + select ZLIB_INFLATE
>> > + help
>> > + This option enables ZLIB compression algorithm support.
>> > +
>> > +config PSTORE_LZO_COMPRESS
>> > + bool "LZO"
>> > + select LZO_COMPRESS
>> > + select LZO_DECOMPRESS
>> > + help
>> > + This option enables LZO compression algorithm support.
>> > +
>> > +config PSTORE_LZ4_COMPRESS
>> > + bool "LZ4"
>> > + select LZ4_COMPRESS
>> > + select LZ4_DECOMPRESS
>> > + help
>> > + This option enables LZ4 compression algorithm support.
>> > +endchoice
>> > +
>> > config PSTORE_CONSOLE
>> > bool "Log kernel console messages"
>> > depends on PSTORE
>> > diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
>> > index 588461b..7246d50 100644
>> > --- a/fs/pstore/platform.c
>> > +++ b/fs/pstore/platform.c
>> > @@ -28,7 +28,15 @@
>> > #include <linux/console.h>
>> > #include <linux/module.h>
>> > #include <linux/pstore.h>
>> > +#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
>> > #include <linux/zlib.h>
>> > +#endif
>> > +#ifdef CONFIG_PSTORE_LZO_COMPRESS
>> > +#include <linux/lzo.h>
>> > +#endif
>> > +#ifdef CONFIG_PSTORE_LZ4_COMPRESS
>> > +#include <linux/lz4.h>
>> > +#endif
>> > #include <linux/string.h>
>> > #include <linux/timer.h>
>> > #include <linux/slab.h>
>> > @@ -69,10 +77,23 @@ struct pstore_info *psinfo;
>> > static char *backend;
>> >
>> > /* Compression parameters */
>> > +#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
>> > #define COMPR_LEVEL 6
>> > #define WINDOW_BITS 12
>> > #define MEM_LEVEL 4
>> > static struct z_stream_s stream;
>> > +#else
>> > +static unsigned char *workspace;
>> > +#endif
>> > +
>> > +struct pstore_zbackend {
>> > + int (*compress)(const void *in, void *out, size_t inlen, size_t outlen);
>> > + int (*decompress)(void *in, void *out, size_t inlen, size_t outlen);
>> > + void (*allocate)(void);
>> > + void (*free)(void);
>> > +
>> > + const char *name;
>> > +};
>> >
>> > static char *big_oops_buf;
>> > static size_t big_oops_buf_sz;
>> > @@ -129,9 +150,9 @@ bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
>> > }
>> > EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
>> >
>> > +#ifdef CONFIG_PSTORE_ZLIB_COMPRESS
>> > /* Derived from logfs_compress() */
>> > -static int pstore_compress(const void *in, void *out, size_t inlen,
>> > - size_t outlen)
>> > +static int compress_zlib(const void *in, void *out, size_t inlen, size_t outlen)
>> > {
>> > int err, ret;
>> >
>> > @@ -165,7 +186,7 @@ error:
>> > }
>> >
>> > /* Derived from logfs_uncompress */
>> > -static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
>> > +static int decompress_zlib(void *in, void *out, size_t inlen, size_t outlen)
>> > {
>> > int err, ret;
>> >
>> > @@ -194,7 +215,7 @@ error:
>> > return ret;
>> > }
>> >
>> > -static void allocate_buf_for_compression(void)
>> > +static void allocate_zlib(void)
>> > {
>> > size_t size;
>> > size_t cmpr;
>> > @@ -237,12 +258,190 @@ static void allocate_buf_for_compression(void)
>> >
>> > }
>> >
>> > -static void free_buf_for_compression(void)
>> > +static void free_zlib(void)
>> > {
>> > kfree(stream.workspace);
>> > stream.workspace = NULL;
>> > kfree(big_oops_buf);
>> > big_oops_buf = NULL;
>> > + big_oops_buf_sz = 0;
>> > +}
>> > +
>> > +static struct pstore_zbackend backend_zlib = {
>> > + .compress = compress_zlib,
>> > + .decompress = decompress_zlib,
>> > + .allocate = allocate_zlib,
>> > + .free = free_zlib,
>> > + .name = "zlib",
>> > +};
>> > +#endif
>> > +
>> > +#ifdef CONFIG_PSTORE_LZO_COMPRESS
>> > +static int compress_lzo(const void *in, void *out, size_t inlen, size_t outlen)
>> > +{
>> > + int ret;
>> > +
>> > + ret = lzo1x_1_compress(in, inlen, out, &outlen, workspace);
>> > + if (ret != LZO_E_OK) {
>> > + pr_err("lzo_compress error, ret = %d!\n", ret);
>> > + return -EIO;
>> > + }
>> > +
>> > + return outlen;
>> > +}
>> > +
>> > +static int decompress_lzo(void *in, void *out, size_t inlen, size_t outlen)
>> > +{
>> > + int ret;
>> > +
>> > + ret = lzo1x_decompress_safe(in, inlen, out, &outlen);
>> > + if (ret != LZO_E_OK) {
>> > + pr_err("lzo_decompress error, ret = %d!\n", ret);
>> > + return -EIO;
>> > + }
>> > +
>> > + return outlen;
>> > +}
>> > +
>> > +static void allocate_lzo(void)
>> > +{
>> > + big_oops_buf_sz = lzo1x_worst_compress(psinfo->bufsize);
>> > + big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
>> > + if (big_oops_buf) {
>> > + workspace = kmalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
>> > + if (!workspace) {
>> > + pr_err("No memory for compression workspace; skipping compression\n");
>> > + kfree(big_oops_buf);
>> > + big_oops_buf = NULL;
>> > + }
>> > + } else {
>> > + pr_err("No memory for uncompressed data; skipping compression\n");
>> > + workspace = NULL;
>> > + }
>> > +}
>> > +
>> > +static void free_lzo(void)
>> > +{
>> > + kfree(workspace);
>> > + kfree(big_oops_buf);
>> > + big_oops_buf = NULL;
>> > + big_oops_buf_sz = 0;
>> > +}
>> > +
>> > +static struct pstore_zbackend backend_lzo = {
>> > + .compress = compress_lzo,
>> > + .decompress = decompress_lzo,
>> > + .allocate = allocate_lzo,
>> > + .free = free_lzo,
>> > + .name = "lzo",
>> > +};
>> > +#endif
>> > +
>> > +#ifdef CONFIG_PSTORE_LZ4_COMPRESS
>> > +static int compress_lz4(const void *in, void *out, size_t inlen, size_t outlen)
>> > +{
>> > + int ret;
>> > +
>> > + ret = lz4_compress(in, inlen, out, &outlen, workspace);
>> > + if (ret) {
>> > + pr_err("lz4_compress error, ret = %d!\n", ret);
>> > + return -EIO;
>> > + }
>> > +
>> > + return outlen;
>> > +}
>> > +
>> > +static int decompress_lz4(void *in, void *out, size_t inlen, size_t outlen)
>> > +{
>> > + int ret;
>> > +
>> > + ret = lz4_decompress_unknownoutputsize(in, inlen, out, &outlen);
>> > + if (ret) {
>> > + pr_err("lz4_decompress error, ret = %d!\n", ret);
>> > + return -EIO;
>> > + }
>> > +
>> > + return outlen;
>> > +}
>> > +
>> > +static void allocate_lz4(void)
>> > +{
>> > + big_oops_buf_sz = lz4_compressbound(psinfo->bufsize);
>> > + big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL);
>> > + if (big_oops_buf) {
>> > + workspace = kmalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
>> > + if (!workspace) {
>> > + pr_err("No memory for compression workspace; skipping compression\n");
>> > + kfree(big_oops_buf);
>> > + big_oops_buf = NULL;
>> > + }
>> > + } else {
>> > + pr_err("No memory for uncompressed data; skipping compression\n");
>> > + workspace = NULL;
>> > + }
>> > +}
>> > +
>> > +static void free_lz4(void)
>> > +{
>> > + kfree(workspace);
>> > + kfree(big_oops_buf);
>> > + big_oops_buf = NULL;
>> > + big_oops_buf_sz = 0;
>> > +}
>> > +
>> > +static struct pstore_zbackend backend_lz4 = {
>> > + .compress = compress_lz4,
>> > + .decompress = decompress_lz4,
>> > + .allocate = allocate_lz4,
>> > + .free = free_lz4,
>> > + .name = "lz4",
>> > +};
>> > +#endif
>> > +
>> > +static struct pstore_zbackend *zbackend =
>> > +#if defined(CONFIG_PSTORE_ZLIB_COMPRESS)
>> > + &backend_zlib;
>> > +#elif defined(CONFIG_PSTORE_LZO_COMPRESS)
>> > + &backend_lzo;
>> > +#elif defined(CONFIG_PSTORE_LZ4_COMPRESS)
>> > + &backend_lz4;
>> > +#else
>> > + NULL;
>> > +#endif
>> > +
>> > +static int pstore_compress(const void *in, void *out,
>> > + size_t inlen, size_t outlen)
>> > +{
>> > + if (zbackend)
>> > + return zbackend->compress(in, out, inlen, outlen);
>> > + else
>> > + return -EIO;
>> > +}
>> > +
>> > +static int pstore_decompress(void *in, void *out, size_t inlen, size_t outlen)
>> > +{
>> > + if (zbackend)
>> > + return zbackend->decompress(in, out, inlen, outlen);
>> > + else
>> > + return -EIO;
>> > +}
>> > +
>> > +static void allocate_buf_for_compression(void)
>> > +{
>> > + if (zbackend) {
>> > + pr_info("using %s compression\n", zbackend->name);
>> > + zbackend->allocate();
>> > + } else {
>> > + pr_err("allocate compression buffer error!\n");
>> > + }
>> > +}
>> > +
>> > +static void free_buf_for_compression(void)
>> > +{
>> > + if (zbackend)
>> > + zbackend->free();
>> > + else
>> > + pr_err("free compression buffer error!\n");
>> > }
>> >
>> > /*
>> > @@ -527,6 +726,7 @@ void pstore_get_records(int quiet)
>> > int failed = 0, rc;
>> > bool compressed;
>> > int unzipped_len = -1;
>> > + ssize_t ecc_notice_size = 0;
>> >
>> > if (!psi)
>> > return;
>> > @@ -536,7 +736,7 @@ void pstore_get_records(int quiet)
>> > goto out;
>> >
>> > while ((size = psi->read(&id, &type, &count, &time, &buf, &compressed,
>> > - psi)) > 0) {
>> > + &ecc_notice_size, psi)) > 0) {
>> > if (compressed && (type == PSTORE_TYPE_DMESG)) {
>> > if (big_oops_buf)
>> > unzipped_len = pstore_decompress(buf,
>> > @@ -544,6 +744,9 @@ void pstore_get_records(int quiet)
>> > big_oops_buf_sz);
>> >
>> > if (unzipped_len > 0) {
>> > + if (ecc_notice_size)
>> > + memcpy(big_oops_buf + unzipped_len,
>> > + buf + size, ecc_notice_size);
>> > kfree(buf);
>> > buf = big_oops_buf;
>> > size = unzipped_len;
>> > @@ -555,7 +758,8 @@ void pstore_get_records(int quiet)
>> > }
>> > }
>> > rc = pstore_mkfile(type, psi->name, id, count, buf,
>> > - compressed, (size_t)size, time, psi);
>> > + compressed, size + ecc_notice_size,
>> > + time, psi);
>> > if (unzipped_len < 0) {
>> > /* Free buffer other than big oops */
>> > kfree(buf);
>> > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
>> > index 319c3a6..11ec024 100644
>> > --- a/fs/pstore/ram.c
>> > +++ b/fs/pstore/ram.c
>> > @@ -181,10 +181,10 @@ static bool prz_ok(struct persistent_ram_zone *prz)
>> > static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
>> > int *count, struct timespec *time,
>> > char **buf, bool *compressed,
>> > + ssize_t *ecc_notice_size,
>> > struct pstore_info *psi)
>> > {
>> > ssize_t size;
>> > - ssize_t ecc_notice_size;
>> > struct ramoops_context *cxt = psi->data;
>> > struct persistent_ram_zone *prz = NULL;
>> > int header_length = 0;
>> > @@ -229,16 +229,16 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
>> > size = persistent_ram_old_size(prz) - header_length;
>> >
>> > /* ECC correction notice */
>> > - ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
>> > + *ecc_notice_size = persistent_ram_ecc_string(prz, NULL, 0);
>> >
>> > - *buf = kmalloc(size + ecc_notice_size + 1, GFP_KERNEL);
>> > + *buf = kmalloc(size + *ecc_notice_size + 1, GFP_KERNEL);
>> > if (*buf == NULL)
>> > return -ENOMEM;
>> >
>> > memcpy(*buf, (char *)persistent_ram_old(prz) + header_length, size);
>> > - persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
>> > + persistent_ram_ecc_string(prz, *buf + size, *ecc_notice_size + 1);
>> >
>> > - return size + ecc_notice_size;
>> > + return size;
>> > }
>> >
>> > static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
>> > diff --git a/include/linux/pstore.h b/include/linux/pstore.h
>> > index 831479f..899e95e 100644
>> > --- a/include/linux/pstore.h
>> > +++ b/include/linux/pstore.h
>> > @@ -58,7 +58,8 @@ struct pstore_info {
>> > int (*close)(struct pstore_info *psi);
>> > ssize_t (*read)(u64 *id, enum pstore_type_id *type,
>> > int *count, struct timespec *time, char **buf,
>> > - bool *compressed, struct pstore_info *psi);
>> > + bool *compressed, ssize_t *ecc_notice_size,
>> > + struct pstore_info *psi);
>> > int (*write)(enum pstore_type_id type,
>> > enum kmsg_dump_reason reason, u64 *id,
>> > unsigned int part, int count, bool compressed,
>> > --
>> > 2.5.0
>> >
>> >
>>
>>
>>
>> --
>> Kees Cook
>> Chrome OS & Brillo Security
>
--
Kees Cook
Chrome OS & Brillo Security