strlcpy() reads the entire source buffer first. This read may exceed the destination size limit. This is both inefficient and can lead to linear read overflows if a source string is not NUL-terminated [1]. In an effort to remove strlcpy() completely [2], replace strlcpy() here with strscpy(). Direct replacement is safe here since return value of -errno is used to check for truncation instead of sizeof(dest). [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy [2] https://github.com/KSPP/linux/issues/89 Signed-off-by: Azeem Shaikh <azeemshaikh38@xxxxxxxxx> --- v3: * Removed declaration of @len to fix build failures in v2. v2: * https://lore.kernel.org/all/20230614141026.2113749-1-azeemshaikh38@xxxxxxxxx/ * Use "< 0" instead of "== -E2BIG". v1: * https://lore.kernel.org/all/20230613004402.3540432-1-azeemshaikh38@xxxxxxxxx/ drivers/usb/usbip/stub_main.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/usb/usbip/stub_main.c b/drivers/usb/usbip/stub_main.c index e8c3131a8543..0a6624d37929 100644 --- a/drivers/usb/usbip/stub_main.c +++ b/drivers/usb/usbip/stub_main.c @@ -167,15 +167,13 @@ static ssize_t match_busid_show(struct device_driver *drv, char *buf) static ssize_t match_busid_store(struct device_driver *dev, const char *buf, size_t count) { - int len; char busid[BUSID_SIZE]; if (count < 5) return -EINVAL; /* busid needs to include \0 termination */ - len = strlcpy(busid, buf + 4, BUSID_SIZE); - if (sizeof(busid) <= len) + if (strscpy(busid, buf + 4, BUSID_SIZE) < 0) return -EINVAL; if (!strncmp(buf, "add ", 4)) { -- 2.41.0.162.gfafddb0af9-goog
