Commit 82c5561b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pstore-v6.6-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux 

Pull pstore fix from Kees Cook:

 - Adjust sizes of buffers just avoid uncompress failures (Ard
   Biesheuvel)

* tag 'pstore-v6.6-rc1-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore: Base compression input buffer size on estimated compressed size
parents fdde6187 94160062

fs/pstore/platform.c

+27 −7
Original line number Diff line number Diff line
@@ -98,7 +98,14 @@ MODULE_PARM_DESC(kmsg_bytes, "amount of kernel log to snapshot (in bytes)"); 


static void *compress_workspace;



/*

 * Compression is only used for dmesg output, which consists of low-entropy

 * ASCII text, and so we can assume worst-case 60%.

 */

#define DMESG_COMP_PERCENT	60



static char *big_oops_buf;

static size_t max_compressed_size;



void pstore_set_kmsg_bytes(int bytes)

{
@@ -196,6 +203,7 @@ static int pstore_compress(const void *in, void *out, 


static void allocate_buf_for_compression(void)

{

	size_t compressed_size;

	char *buf;



	/* Skip if not built-in or compression disabled. */
@@ -216,7 +224,8 @@ static void allocate_buf_for_compression(void) 
	 * uncompressed record size, since any record that would be expanded by

	 * compression is just stored uncompressed.

	 */

	buf = kvzalloc(psinfo->bufsize, GFP_KERNEL);

	compressed_size = (psinfo->bufsize * 100) / DMESG_COMP_PERCENT;

	buf = kvzalloc(compressed_size, GFP_KERNEL);

	if (!buf) {

		pr_err("Failed %zu byte compression buffer allocation for: %s\n",

		       psinfo->bufsize, compress);
@@ -233,6 +242,7 @@ static void allocate_buf_for_compression(void) 


	/* A non-NULL big_oops_buf indicates compression is available. */

	big_oops_buf = buf;

	max_compressed_size = compressed_size;



	pr_info("Using crash dump compression: %s\n", compress);

}
@@ -246,6 +256,7 @@ static void free_buf_for_compression(void) 


	kvfree(big_oops_buf);

	big_oops_buf = NULL;

	max_compressed_size = 0;

}



void pstore_record_init(struct pstore_record *record,
@@ -305,7 +316,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, 
		record.buf = psinfo->buf;



		dst = big_oops_buf ?: psinfo->buf;

		dst_size = psinfo->bufsize;

		dst_size = max_compressed_size ?: psinfo->bufsize;



		/* Write dump header. */

		header_size = snprintf(dst, dst_size, "%s#%d Part%u\n", why,
@@ -326,8 +337,15 @@ static void pstore_dump(struct kmsg_dumper *dumper, 
				record.compressed = true;

				record.size = zipped_len;

			} else {

				record.size = header_size + dump_size;

				memcpy(psinfo->buf, dst, record.size);

				/*

				 * Compression failed, so the buffer is most

				 * likely filled with binary data that does not

				 * compress as well as ASCII text. Copy as much

				 * of the uncompressed data as possible into

				 * the pstore record, and discard the rest.

				 */

				record.size = psinfo->bufsize;

				memcpy(psinfo->buf, dst, psinfo->bufsize);

			}

		} else {

			record.size = header_size + dump_size;
@@ -560,6 +578,7 @@ static void decompress_record(struct pstore_record *record, 
	int ret;

	int unzipped_len;

	char *unzipped, *workspace;

	size_t max_uncompressed_size;



	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)

		return;
@@ -583,7 +602,8 @@ static void decompress_record(struct pstore_record *record, 
	}



	/* Allocate enough space to hold max decompression and ECC. */

	workspace = kvzalloc(psinfo->bufsize + record->ecc_notice_size,

	max_uncompressed_size = 3 * psinfo->bufsize;

	workspace = kvzalloc(max_uncompressed_size + record->ecc_notice_size,

			     GFP_KERNEL);

	if (!workspace)

		return;
@@ -591,11 +611,11 @@ static void decompress_record(struct pstore_record *record, 
	zstream->next_in	= record->buf;

	zstream->avail_in	= record->size;

	zstream->next_out	= workspace;

	zstream->avail_out	= psinfo->bufsize;

	zstream->avail_out	= max_uncompressed_size;



	ret = zlib_inflate(zstream, Z_FINISH);

	if (ret != Z_STREAM_END) {

		pr_err("zlib_inflate() failed, ret = %d!\n", ret);

		pr_err_ratelimited("zlib_inflate() failed, ret = %d!\n", ret);

		kvfree(workspace);

		return;

	}