| Message ID | 20230918-strncpy-drivers-edac-edac_mc_sysfs-c-v4-1-38a23d2fcdd8@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4] EDAC/mc_sysfs: refactor deprecated strncpy | expand |
On Mon, Sep 18, 2023 at 07:47:29AM +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We've already calculated bounds, possible truncation with '\0' or '\n' > and manually NUL-terminated. The situation is now just a literal byte > copy from one buffer to another, let's treat it as such and use a less > ambiguous interface in memcpy. > > 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 > Signed-off-by: Justin Stitt <justinstitt@google.com> Yeah, I think this looks good now. If a v5 is needed, a tiny improvement would be to update the Subject: to "...: replace strncpy with memcpy". Reviewed-by: Kees Cook <keescook@chromium.org> -Kees
On Mon, 18 Sep 2023 07:47:29 +0000, Justin Stitt wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings [1]. > > We've already calculated bounds, possible truncation with '\0' or '\n' > and manually NUL-terminated. The situation is now just a literal byte > copy from one buffer to another, let's treat it as such and use a less > ambiguous interface in memcpy. > > [...] Applied to for-next/hardening, thanks! (Subject updated...) Take care,
diff --git a/drivers/edac/edac_mc_sysfs.c b/drivers/edac/edac_mc_sysfs.c index 15f63452a9be..5116873c3330 100644 --- a/drivers/edac/edac_mc_sysfs.c +++ b/drivers/edac/edac_mc_sysfs.c @@ -229,7 +229,7 @@ static ssize_t channel_dimm_label_store(struct device *dev, if (copy_count == 0 || copy_count >= sizeof(rank->dimm->label)) return -EINVAL; - strncpy(rank->dimm->label, data, copy_count); + memcpy(rank->dimm->label, data, copy_count); rank->dimm->label[copy_count] = '\0'; return count; @@ -535,7 +535,7 @@ static ssize_t dimmdev_label_store(struct device *dev, if (copy_count == 0 || copy_count >= sizeof(dimm->label)) return -EINVAL; - strncpy(dimm->label, data, copy_count); + memcpy(dimm->label, data, copy_count); dimm->label[copy_count] = '\0'; return count;
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. We've already calculated bounds, possible truncation with '\0' or '\n' and manually NUL-terminated. The situation is now just a literal byte copy from one buffer to another, let's treat it as such and use a less ambiguous interface in memcpy. 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 Signed-off-by: Justin Stitt <justinstitt@google.com> --- Changes in v4: - prefer memcpy to strscpy (thanks Kees) - Link to v3: https://lore.kernel.org/r/20230913-strncpy-drivers-edac-edac_mc_sysfs-c-v3-1-38c1db7d207f@google.com Changes in v3: - prefer strscpy to strscpy_pad (thanks Tony) - Link to v2: https://lore.kernel.org/r/20230913-strncpy-drivers-edac-edac_mc_sysfs-c-v2-1-2d2e6bd43642@google.com Changes in v2: - included refactor of another strncpy in same file - Link to v1: https://lore.kernel.org/r/20230913-strncpy-drivers-edac-edac_mc_sysfs-c-v1-1-d232891b05b0@google.com --- Note: build-tested only. --- drivers/edac/edac_mc_sysfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c change-id: 20230913-strncpy-drivers-edac-edac_mc_sysfs-c-e619b00124a3 Best regards, -- Justin Stitt <justinstitt@google.com>