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pstore/blk: replace deprecated strncpy with strscpy

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strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.

We know that info-device should be NUL-terminated based on its use with
strlen():
|	static int __init mtdpstore_init(void)
|	{
|		int ret;
|		struct mtdpstore_context *cxt = &oops_cxt;
|		struct pstore_blk_config *info = &cxt->info;
|
|		ret = pstore_blk_get_config(info);
|		if (unlikely(ret))
|			return ret;
|
|		if (strlen(info->device) == 0) {
|			pr_err("mtd device must be supplied (device name is empty)\n");
...

Considering the above, a suitable replacement is `strscpy` [2] due to
the fact that it guarantees NUL-termination on the destination buffer.

Note that this patch relies on the _new_ 2-argument version of strscpy()
introduced in Commit e6584c3964 ("string: Allow 2-argument strscpy()").

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc:  <linux-hardening@vger.kernel.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://lore.kernel.org/r/20240328-strncpy-fs-pstore-blk-c-v1-1-5748cdc22a53@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Justin Stitt 2024-03-28 20:54:16 +00:00 committed by Kees Cook
parent 39cd87c4eb
commit 9dd12ed95c
1 changed files with 1 additions and 1 deletions
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2
fs/pstore/blk.c
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@ -241,7 +241,7 @@ err:
/* get information of pstore/blk */ /* get information of pstore/blk */
int pstore_blk_get_config(struct pstore_blk_config *info) int pstore_blk_get_config(struct pstore_blk_config *info)
{ {
strncpy(info->device, blkdev, 80); strscpy(info->device, blkdev);
info->max_reason = max_reason; info->max_reason = max_reason;
info->kmsg_size = check_size(kmsg_size, 4096); info->kmsg_size = check_size(kmsg_size, 4096);
info->pmsg_size = check_size(pmsg_size, 4096); info->pmsg_size = check_size(pmsg_size, 4096);