From f0a6b5831cfb17381ada015778448b12c1c6179e Mon Sep 17 00:00:00 2001 From: Azeem Shaikh Date: Wed, 14 Jun 2023 00:36:04 +0000 Subject: uml: Replace strlcpy with strscpy 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(). No return values were used, so direct replacement is safe. [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 Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20230614003604.1021205-1-azeemshaikh38@gmail.com --- arch/um/include/shared/user.h | 1 + arch/um/os-Linux/drivers/tuntap_user.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/um') diff --git a/arch/um/include/shared/user.h b/arch/um/include/shared/user.h index bda66e5a9d4e..0347a190429c 100644 --- a/arch/um/include/shared/user.h +++ b/arch/um/include/shared/user.h @@ -52,6 +52,7 @@ static inline int printk(const char *fmt, ...) extern int in_aton(char *str); extern size_t strlcpy(char *, const char *, size_t); extern size_t strlcat(char *, const char *, size_t); +extern size_t strscpy(char *, const char *, size_t); /* Copied from linux/compiler-gcc.h since we can't include it directly */ #define barrier() __asm__ __volatile__("": : :"memory") diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c index 53eb3d508645..2284e9c1cbbb 100644 --- a/arch/um/os-Linux/drivers/tuntap_user.c +++ b/arch/um/os-Linux/drivers/tuntap_user.c @@ -146,7 +146,7 @@ static int tuntap_open(void *data) } memset(&ifr, 0, sizeof(ifr)); ifr.ifr_flags = IFF_TAP | IFF_NO_PI; - strlcpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name)); + strscpy(ifr.ifr_name, pri->dev_name, sizeof(ifr.ifr_name)); if (ioctl(pri->fd, TUNSETIFF, &ifr) < 0) { err = -errno; printk(UM_KERN_ERR "TUNSETIFF failed, errno = %d\n", -- cgit v1.2.3