| Message ID | 20231018-strncpy-drivers-net-wireless-ti-wlcore-boot-c-v1-1-d3c6cc6b80fe@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | wifi: wlcore: replace deprecated strncpy with strscpy | expand |
Justin Stitt <justinstitt@google.com> 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. > > We expect wl->chip.fw_ver_str to be NUL-terminated based on its usage > with DRIVER_STATE_PRINT_STR() in debugfs.c: > 491 | DRIVER_STATE_PRINT_STR(chip.fw_ver_str); > ... which uses DRIVER_STATE_PRINT(): > 444 | #define DRIVER_STATE_PRINT_STR(x) DRIVER_STATE_PRINT(x, "%s") > ... which relies on scnprintf: > 434 | #define DRIVER_STATE_PRINT(x, fmt) \ > 435 | (res += scnprintf(buf + res, DRIVER_STATE_BUF_LEN - res,\ > 436 | #x " = " fmt "\n", wl->x)) > > Moreover, NUL-padding is not required. > > Considering the above, a suitable replacement is `strscpy` [2] due to > the fact that it guarantees NUL-termination on the destination buffer > without unnecessarily NUL-padding. > > 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 > Similar-to: https://lore.kernel.org/all/20231018-strncpy-drivers-net-wireless-ti-wl18xx-main-c-v2-1-ab828a491ce5@google.com/ > Signed-off-by: Justin Stitt <justinstitt@google.com> > Reviewed-by: Kees Cook <keescook@chromium.org> Patch applied to wireless-next.git, thanks. 75fdaa28f103 wifi: wlcore: boot: replace deprecated strncpy with strscpy
diff --git a/drivers/net/wireless/ti/wlcore/boot.c b/drivers/net/wireless/ti/wlcore/boot.c index 85abd0a2d1c9..f481c2e3dbc8 100644 --- a/drivers/net/wireless/ti/wlcore/boot.c +++ b/drivers/net/wireless/ti/wlcore/boot.c @@ -41,12 +41,9 @@ static int wlcore_boot_parse_fw_ver(struct wl1271 *wl, { int ret; - strncpy(wl->chip.fw_ver_str, static_data->fw_version, + strscpy(wl->chip.fw_ver_str, static_data->fw_version, sizeof(wl->chip.fw_ver_str)); - /* make sure the string is NULL-terminated */ - wl->chip.fw_ver_str[sizeof(wl->chip.fw_ver_str) - 1] = '\0'; - ret = sscanf(wl->chip.fw_ver_str + 4, "%u.%u.%u.%u.%u", &wl->chip.fw_ver[0], &wl->chip.fw_ver[1], &wl->chip.fw_ver[2], &wl->chip.fw_ver[3],
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 wl->chip.fw_ver_str to be NUL-terminated based on its usage with DRIVER_STATE_PRINT_STR() in debugfs.c: 491 | DRIVER_STATE_PRINT_STR(chip.fw_ver_str); ... which uses DRIVER_STATE_PRINT(): 444 | #define DRIVER_STATE_PRINT_STR(x) DRIVER_STATE_PRINT(x, "%s") ... which relies on scnprintf: 434 | #define DRIVER_STATE_PRINT(x, fmt) \ 435 | (res += scnprintf(buf + res, DRIVER_STATE_BUF_LEN - res,\ 436 | #x " = " fmt "\n", wl->x)) Moreover, NUL-padding is not required. Considering the above, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. 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 Similar-to: https://lore.kernel.org/all/20231018-strncpy-drivers-net-wireless-ti-wl18xx-main-c-v2-1-ab828a491ce5@google.com/ Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/wireless/ti/wlcore/boot.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) --- base-commit: 58720809f52779dc0f08e53e54b014209d13eebb change-id: 20231018-strncpy-drivers-net-wireless-ti-wlcore-boot-c-b318a8677793 Best regards, -- Justin Stitt <justinstitt@google.com>