From be8dffa04de3894bad0bf31d1531a2f06353b70e Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Wed, 9 Aug 2023 18:19:32 +0000 Subject: um: refactor deprecated strncpy to memcpy Use `memcpy` since `console_buf` is not expected to be NUL-terminated and it more accurately describes what is happening with the buffers `console_buf` and `string` as per Kees' analysis [1]. Also mark char buffer as `__nonstring` as per Kees' suggestion [2]. This change now makes it more clear what this code does and that `console_buf` is not expected to be NUL-terminated. Link: https://lore.kernel.org/all/202308081708.D5ADC80F@keescook/ [1] Link: https://github.com/KSPP/linux/issues/90 [2] Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings Cc: linux-hardening@vger.kernel.org Suggested-by: Kees Cook Signed-off-by: Justin Stitt Link: https://lore.kernel.org/r/20230809-arch-um-v3-1-f63e1122d77e@google.com Signed-off-by: Kees Cook --- arch/um/drivers/mconsole_kern.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/um/drivers/mconsole_kern.c') diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c index 5026e7b9adfe..ff4bda95b9c7 100644 --- a/arch/um/drivers/mconsole_kern.c +++ b/arch/um/drivers/mconsole_kern.c @@ -554,7 +554,7 @@ struct mconsole_output { static DEFINE_SPINLOCK(client_lock); static LIST_HEAD(clients); -static char console_buf[MCONSOLE_MAX_DATA]; +static char console_buf[MCONSOLE_MAX_DATA] __nonstring; static void console_write(struct console *console, const char *string, unsigned int len) @@ -567,7 +567,7 @@ static void console_write(struct console *console, const char *string, while (len > 0) { n = min((size_t) len, ARRAY_SIZE(console_buf)); - strncpy(console_buf, string, n); + memcpy(console_buf, string, n); string += n; len -= n; -- cgit v1.2.3