From 7b9ef666f27afde43c047de2be2985b68ad9febe Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Thu, 3 Aug 2023 21:33:44 +0000 Subject: tomoyo: refactor deprecated strncpy `strncpy` is deprecated for use on NUL-terminated destination strings [1]. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on its destination buffer argument which is _not_ the case for `strncpy`! It should be noted that the destination buffer is zero-initialized and had a max length of `sizeof(dest) - 1`. There is likely _not_ a bug present in the current implementation. However, by switching to `strscpy` we get the benefit of no longer needing the `- 1`'s from the string copy invocations on top of `strscpy` being a safer interface all together. [1]: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [2]: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Reviewed-by: Kees Cook Signed-off-by: Tetsuo Handa --- security/tomoyo/domain.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'security/tomoyo') diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c index ac20c0bdff9d..90b53500a236 100644 --- a/security/tomoyo/domain.c +++ b/security/tomoyo/domain.c @@ -784,13 +784,12 @@ retry: if (!strcmp(domainname, "parent")) { char *cp; - strncpy(ee->tmp, old_domain->domainname->name, - TOMOYO_EXEC_TMPSIZE - 1); + strscpy(ee->tmp, old_domain->domainname->name, TOMOYO_EXEC_TMPSIZE); cp = strrchr(ee->tmp, ' '); if (cp) *cp = '\0'; } else if (*domainname == '<') - strncpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE - 1); + strscpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE); else snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s", old_domain->domainname->name, domainname); -- cgit