Messages in this thread Patch in this message | | | Date | Thu, 03 Aug 2023 21:33:44 +0000 | Subject | [PATCH] tomoyo: refactor deprecated strncpy | From | Justin Stitt <> |
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`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 <justinstitt@google.com> --- security/tomoyo/domain.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
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 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm) 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); --- base-commit: 5d0c230f1de8c7515b6567d9afba1f196fb4e2f4 change-id: 20230803-security-tomoyo-7d58f53d35a6 Best regards, -- Justin Stitt <justinstitt@google.com>
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