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Commit 7e8cc8dc authored by Kees Cook's avatar Kees Cook
Browse files

pstore: Always allocate buffer for decompression 



Currently, pstore_mkfile() performs a memcpy() of the record contents,
so it can live anywhere. However, this is needlessly wasteful. In
preparation of pstore_mkfile() keeping the record contents, always
allocate a buffer for the contents.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 76cc9580

fs/pstore/platform.c

+24 −14
Original line number Diff line number Diff line
@@ -768,6 +768,7 @@ EXPORT_SYMBOL_GPL(pstore_unregister); 
static void decompress_record(struct pstore_record *record)

{

	int unzipped_len;

	char *decompressed;



	/* Only PSTORE_TYPE_DMESG support compression. */

	if (!record->compressed || record->type != PSTORE_TYPE_DMESG) {
@@ -783,17 +784,29 @@ static void decompress_record(struct pstore_record *record) 


	unzipped_len = pstore_decompress(record->buf, big_oops_buf,

					 record->size, big_oops_buf_sz);

	if (unzipped_len > 0) {

		if (record->ecc_notice_size)

			memcpy(big_oops_buf + unzipped_len,

			       record->buf + record->size,

	if (unzipped_len <= 0) {

		pr_err("decompression failed: %d\n", unzipped_len);

		return;

	}



	/* Build new buffer for decompressed contents. */

	decompressed = kmalloc(unzipped_len + record->ecc_notice_size,

			       GFP_KERNEL);

	if (!decompressed) {

		pr_err("decompression ran out of memory\n");

		return;

	}

	memcpy(decompressed, big_oops_buf, unzipped_len);



	/* Append ECC notice to decompressed buffer. */

	memcpy(decompressed + unzipped_len, record->buf + record->size,

	       record->ecc_notice_size);



	/* Swap out compresed contents with decompressed contents. */

	kfree(record->buf);

		record->buf = big_oops_buf;

	record->buf = decompressed;

	record->size = unzipped_len;

	record->compressed = false;

	} else

		pr_err("decompression failed: %d\n", unzipped_len);

}



/*
@@ -819,13 +832,10 @@ void pstore_get_records(int quiet) 
		decompress_record(&record);

		rc = pstore_mkfile(&record);



		/* Free buffer other than big oops */

		if (record.buf != big_oops_buf)

			kfree(record.buf);



		if (rc && (rc != -EEXIST || !quiet))

			failed++;



		kfree(record.buf);

		memset(&record, 0, sizeof(record));

		record.psi = psi;

	}