| Message ID | 20231017-strncpy-drivers-net-wireless-ti-wl1251-acx-c-v1-1-a99584e82f65@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | wl1251: replace deprecated strncpy with strscpy | expand |
diff --git a/drivers/net/wireless/ti/wl1251/acx.c b/drivers/net/wireless/ti/wl1251/acx.c index f78fc3880423..ed5733e0dd5e 100644 --- a/drivers/net/wireless/ti/wl1251/acx.c +++ b/drivers/net/wireless/ti/wl1251/acx.c @@ -149,15 +149,7 @@ int wl1251_acx_fw_version(struct wl1251 *wl, char *buf, size_t len) goto out; } - /* be careful with the buffer sizes */ - strncpy(buf, rev->fw_version, min(len, sizeof(rev->fw_version))); - - /* - * if the firmware version string is exactly - * sizeof(rev->fw_version) long or fw_len is less than - * sizeof(rev->fw_version) it won't be null terminated - */ - buf[min(len, sizeof(rev->fw_version)) - 1] = '\0'; + strscpy(buf, rev->fw_version, len); out: kfree(rev);
strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. There was a lot of effort done here to ensure buf is NUL-terminated. We now have access to better string apis -- `buf` should be NUL-terminated and doesn't seem to require NUL-padding as its only use is with format strings in wl1251/main.c 403 | wl1251_info("firmware booted (%s)", wl->fw_ver); Therefore, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Do note that there is only one caller of wl1251_acx_fw_version() in drivers/net/wireless/ti/wl1251/boot.c: 264 | wl1251_acx_fw_version(wl, wl->fw_ver, sizeof(wl->fw_ver)); ... which passes wl->fw_ver and sizeof(wl->fw_ver) wherein fw_ver is defined as having size 21 in wl1251.h: 383 | char fw_ver[21]; ... and since fw_version has a size of 20 in acx.h: 66 | char fw_version[20]; ... there is no overflow or truncation because sizeof(dest) > sizeof(src). 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 Signed-off-by: Justin Stitt <justinstitt@google.com> --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/wireless/ti/wl1251/acx.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) --- base-commit: 58720809f52779dc0f08e53e54b014209d13eebb change-id: 20231017-strncpy-drivers-net-wireless-ti-wl1251-acx-c-47ebc6ad4435 Best regards, -- Justin Stitt <justinstitt@google.com>