All of lore.kernel.org
 help / color / mirror / Atom feed
From: Justin Stitt <justinstitt@google.com>
To: Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@kernel.org>,
	dm-devel@redhat.com
Cc: Justin Stitt <justinstitt@google.com>,
	linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
	linux-hardening@vger.kernel.org
Subject: [dm-devel] [PATCH] dm crypt: replace open-coded kmemdup_nul
Date: Mon, 25 Sep 2023 06:35:54 +0000	[thread overview]
Message-ID: <20230925-strncpy-drivers-md-dm-crypt-c-v1-1-eef875e4f9b2@google.com> (raw)

kzalloc() followed by strncpy() on an expected NUL-terminated string is
just kmemdup_nul(). Let's simplify this code (while also dropping a
deprecated strncpy() call [1]).

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Note: build-tested only.
Similar-to: https://lore.kernel.org/all/20230925-strncpy-drivers-hwmon-acpi_power_meter-c-v4-1-3bac7534f10f@google.com/
---
 drivers/md/dm-crypt.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f2662c21a6df..8a03b3590733 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2858,10 +2858,9 @@ static int crypt_ctr_auth_cipher(struct crypt_config *cc, char *cipher_api)
 	if (!start || !end || ++start > end)
 		return -EINVAL;
 
-	mac_alg = kzalloc(end - start + 1, GFP_KERNEL);
+	mac_alg = kmemdup_nul(start, end - start, GFP_KERNEL);
 	if (!mac_alg)
 		return -ENOMEM;
-	strncpy(mac_alg, start, end - start);
 
 	mac = crypto_alloc_ahash(mac_alg, 0, CRYPTO_ALG_ALLOCATES_MEMORY);
 	kfree(mac_alg);

---
base-commit: 6465e260f48790807eef06b583b38ca9789b6072
change-id: 20230925-strncpy-drivers-md-dm-crypt-c-da71d87b8cdc

Best regards,
--
Justin Stitt <justinstitt@google.com>

--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel


WARNING: multiple messages have this Message-ID (diff)
From: Justin Stitt <justinstitt@google.com>
To: Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@kernel.org>,
	dm-devel@redhat.com
Cc: linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	 Kees Cook <keescook@chromium.org>,
	Justin Stitt <justinstitt@google.com>
Subject: [PATCH] dm crypt: replace open-coded kmemdup_nul
Date: Mon, 25 Sep 2023 06:35:54 +0000	[thread overview]
Message-ID: <20230925-strncpy-drivers-md-dm-crypt-c-v1-1-eef875e4f9b2@google.com> (raw)

kzalloc() followed by strncpy() on an expected NUL-terminated string is
just kmemdup_nul(). Let's simplify this code (while also dropping a
deprecated strncpy() call [1]).

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
---
Note: build-tested only.
Similar-to: https://lore.kernel.org/all/20230925-strncpy-drivers-hwmon-acpi_power_meter-c-v4-1-3bac7534f10f@google.com/
---
 drivers/md/dm-crypt.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f2662c21a6df..8a03b3590733 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2858,10 +2858,9 @@ static int crypt_ctr_auth_cipher(struct crypt_config *cc, char *cipher_api)
 	if (!start || !end || ++start > end)
 		return -EINVAL;
 
-	mac_alg = kzalloc(end - start + 1, GFP_KERNEL);
+	mac_alg = kmemdup_nul(start, end - start, GFP_KERNEL);
 	if (!mac_alg)
 		return -ENOMEM;
-	strncpy(mac_alg, start, end - start);
 
 	mac = crypto_alloc_ahash(mac_alg, 0, CRYPTO_ALG_ALLOCATES_MEMORY);
 	kfree(mac_alg);

---
base-commit: 6465e260f48790807eef06b583b38ca9789b6072
change-id: 20230925-strncpy-drivers-md-dm-crypt-c-da71d87b8cdc

Best regards,
--
Justin Stitt <justinstitt@google.com>


             reply	other threads:[~2023-09-25 18:36 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-25  6:35 Justin Stitt [this message]
2023-09-25  6:35 ` [PATCH] dm crypt: replace open-coded kmemdup_nul Justin Stitt
2023-09-25 18:04 ` [dm-devel] " Kees Cook
2023-09-25 18:04   ` Kees Cook
2023-10-24 21:18 ` Kees Cook
2023-10-24 21:18   ` Kees Cook
2023-10-24 21:33   ` Mike Snitzer
2023-10-24 21:35     ` 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=20230925-strncpy-drivers-md-dm-crypt-c-v1-1-eef875e4f9b2@google.com \
    --to=justinstitt@google.com \
    --cc=agk@redhat.com \
    --cc=dm-devel@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=snitzer@kernel.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.