From: Justin Stitt <justinstitt@google.com>
To: James Smart <james.smart@broadcom.com>,
Dick Kennedy <dick.kennedy@broadcom.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org,
Justin Stitt <justinstitt@google.com>
Subject: [PATCH] scsi: lpfc: replace deprecated strncpy with strscpy
Date: Thu, 22 Feb 2024 00:41:52 +0000 [thread overview]
Message-ID: <20240222-strncpy-drivers-scsi-lpfc-lpfc_ct-c-v1-1-20c685bd1b43@google.com> (raw)
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 expect ae->value_string to be NUL-terminated because there's a
comment that says as much; these attr strings are also used with other
string APIs, further cementing the fact.
Now, the question of whether or not to NUL-pad the destination buffer:
lpfc_fdmi_rprt_defer() initializes vports (all zero-initialized), then
we call lpfc_fdmi_cmd() with each vport and a mask. Then, inside of
lpfc_fdmi_cmd() we check each bit in the mask to invoke the proper
callback. Importantly, the zero-initialized vport is passed in as the
"attr" parameter. Seeing this:
| struct lpfc_fdmi_attr_string *ae = attr;
... we can tell that ae->value_string is entirely zero-initialized. Due
to this, NUL-padding is _not_ required as it would be redundant.
Conveniently, strscpy also returns the number of bytes copied into the
destination buffer, eliminating the need for strnlen!
Considering the above, a suitable replacement is `strscpy` [2].
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>
---
drivers/scsi/lpfc/lpfc_ct.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc_ct.c b/drivers/scsi/lpfc/lpfc_ct.c
index baae1f8279e0..42594ec87290 100644
--- a/drivers/scsi/lpfc/lpfc_ct.c
+++ b/drivers/scsi/lpfc/lpfc_ct.c
@@ -2569,9 +2569,8 @@ lpfc_fdmi_set_attr_string(void *attr, uint16_t attrtype, char *attrstring)
* 64 bytes or less.
*/
- strncpy(ae->value_string, attrstring, sizeof(ae->value_string));
- len = strnlen(ae->value_string, sizeof(ae->value_string));
- /* round string length to a 32bit boundary. Ensure there's a NULL */
+ len = strscpy(ae->value_string, attrstring, sizeof(ae->value_string));
+ /* round string length to a 32bit boundary */
len += (len & 3) ? (4 - (len & 3)) : 4;
/* size is Type/Len (4 bytes) plus string length */
size = FOURBYTES + len;
---
base-commit: 39133352cbed6626956d38ed72012f49b0421e7b
change-id: 20240222-strncpy-drivers-scsi-lpfc-lpfc_ct-c-f54b67eeeb68
Best regards,
--
Justin Stitt <justinstitt@google.com>
next reply other threads:[~2024-02-22 0:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 0:41 Justin Stitt [this message]
2024-02-22 2:37 ` [PATCH] scsi: lpfc: replace deprecated strncpy with strscpy Kees Cook
2024-02-23 20:02 ` Justin Stitt
2024-02-23 23:44 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240222-strncpy-drivers-scsi-lpfc-lpfc_ct-c-v1-1-20c685bd1b43@google.com \
--to=justinstitt@google.com \
--cc=dick.kennedy@broadcom.com \
--cc=james.smart@broadcom.com \
--cc=jejb@linux.ibm.com \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).