| Message ID | 20230925-strncpy-drivers-md-dm-log-userspace-base-c-v1-1-030d7bcf1004@google.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 18ac52332959aaf4bee54ee1b760959beeb13ae2 |
| Headers | show |
| Series | dm log userspace: replace deprecated strncpy with strscpy | expand |
On Mon, Sep 25, 2023 at 07:06:03AM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings > [1] and as such we should prefer more robust and less ambiguous string > interfaces. > > `lc` is already zero-allocated: > | lc = kzalloc(sizeof(*lc), GFP_KERNEL); > ... as such, any future NUL-padding is superfluous. > > A suitable replacement is `strscpy` [2] due to the fact that it > guarantees NUL-termination on the destination buffer without > unnecessarily NUL-padding. > > Let's also go with the more idiomatic `dest, src, sizeof(dest)` pattern > for destination buffers that the compiler can calculate the size for. > > 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 > Cc: Kees Cook <keescook@chromium.org> > Signed-off-by: Justin Stitt <justinstitt@google.com> Looks good to me. Thanks for the sizeof() replacement. :) Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > --- > Note: build-tested only. > --- > drivers/md/dm-log-userspace-base.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c > index 5aace6ee6d47..7e4f27e86150 100644 > --- a/drivers/md/dm-log-userspace-base.c > +++ b/drivers/md/dm-log-userspace-base.c > @@ -224,7 +224,7 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, > > lc->usr_argc = argc; > > - strncpy(lc->uuid, argv[0], DM_UUID_LEN); > + strscpy(lc->uuid, argv[0], sizeof(lc->uuid)); > argc--; > argv++; > spin_lock_init(&lc->flush_lock); > > --- > base-commit: 6465e260f48790807eef06b583b38ca9789b6072 > change-id: 20230925-strncpy-drivers-md-dm-log-userspace-base-c-857579d9834f > > Best regards, > -- > Justin Stitt <justinstitt@google.com> >
On Mon, 25 Sep 2023 07:06:03 +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings > [1] and as such we should prefer more robust and less ambiguous string > interfaces. > > `lc` is already zero-allocated: > | lc = kzalloc(sizeof(*lc), GFP_KERNEL); > ... as such, any future NUL-padding is superfluous. > > [...] Applied to for-next/hardening, thanks! [1/1] dm log userspace: replace deprecated strncpy with strscpy https://git.kernel.org/kees/c/f8cff5441800 Take care,
diff --git a/drivers/md/dm-log-userspace-base.c b/drivers/md/dm-log-userspace-base.c index 5aace6ee6d47..7e4f27e86150 100644 --- a/drivers/md/dm-log-userspace-base.c +++ b/drivers/md/dm-log-userspace-base.c @@ -224,7 +224,7 @@ static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti, lc->usr_argc = argc; - strncpy(lc->uuid, argv[0], DM_UUID_LEN); + strscpy(lc->uuid, argv[0], sizeof(lc->uuid)); argc--; argv++; spin_lock_init(&lc->flush_lock);
`strncpy` is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. `lc` is already zero-allocated: | lc = kzalloc(sizeof(*lc), GFP_KERNEL); ... as such, any future NUL-padding is superfluous. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Let's also go with the more idiomatic `dest, src, sizeof(dest)` pattern for destination buffers that the compiler can calculate the size for. 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 Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. --- drivers/md/dm-log-userspace-base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 6465e260f48790807eef06b583b38ca9789b6072 change-id: 20230925-strncpy-drivers-md-dm-log-userspace-base-c-857579d9834f Best regards, -- Justin Stitt <justinstitt@google.com>