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 <azeemshaik...@gmail.com> Reported-by: kernel test robot <l...@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202305311135.zgmt1gyr-...@intel.com/ --- v1: https://lore.kernel.org/all/20230530164004.986750-1-azeemshaik...@gmail.com/ Changes from v1 - added strscpy declaration. v1 does not build. arch/um/include/shared/user.h | 1 + arch/um/os-Linux/drivers/tuntap_user.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) 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", -- 2.41.0.rc0.172.g3f132b7071-goog _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um
