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: [email protected]
Cc: Kees Cook <[email protected]>
Signed-off-by: Justin Stitt <[email protected]>
---
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 <[email protected]>
On Mon, Sep 25, 2023 at 06:35:54AM +0000, Justin Stitt wrote:
> 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: [email protected]
> Cc: Kees Cook <[email protected]>
> Signed-off-by: Justin Stitt <[email protected]>
This looks correct to me. Thanks!
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
On Mon, 25 Sep 2023 06:35:54 +0000, Justin Stitt wrote:
> 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]).
>
>
Applied to for-next/hardening, thanks!
[1/1] dm crypt: replace open-coded kmemdup_nul
https://git.kernel.org/kees/c/17348b0a6a6d
Take care,
--
Kees Cook
On Tue, Oct 24 2023 at 5:18P -0400,
Kees Cook <[email protected]> wrote:
> On Mon, 25 Sep 2023 06:35:54 +0000, Justin Stitt wrote:
> > 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]).
> >
> >
>
> Applied to for-next/hardening, thanks!
>
> [1/1] dm crypt: replace open-coded kmemdup_nul
> https://git.kernel.org/kees/c/17348b0a6a6d
>
> Take care,
>
> --
> Kees Cook
>
Hey,
I had picked up this patch and the 3 others in my local tree
yesterday, was going to push shortly... do you still want them to go
through your hardening tree?
Mike
On Tue, Oct 24, 2023 at 05:33:12PM -0400, Mike Snitzer wrote:
> On Tue, Oct 24 2023 at 5:18P -0400,
> Kees Cook <[email protected]> wrote:
>
> > On Mon, 25 Sep 2023 06:35:54 +0000, Justin Stitt wrote:
> > > 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]).
> > >
> > >
> >
> > Applied to for-next/hardening, thanks!
> >
> > [1/1] dm crypt: replace open-coded kmemdup_nul
> > https://git.kernel.org/kees/c/17348b0a6a6d
> >
> > Take care,
> >
> > --
> > Kees Cook
> >
>
> I had picked up this patch and the 3 others in my local tree
> yesterday, was going to push shortly... do you still want them to go
> through your hardening tree?
Oh! Great; thank you! I'll drop them from my tree. :)
-Kees
--
Kees Cook