From: Azeem Shaikh <azeemshaikh38@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: linux-hardening@vger.kernel.org,
	"Azeem Shaikh" <azeemshaikh38@gmail.com>,
	linux-kernel@vger.kernel.org,
	"Masahiro Yamada" <masahiroy@kernel.org>,
	"Thomas Weißschuh" <linux@weissschuh.net>
Subject: [PATCH] init/version.c: Replace strlcpy with strscpy
Date: Wed, 30 Aug 2023 16:08:06 +0000	[thread overview]
Message-ID: <20230830160806.3821893-1-azeemshaikh38@gmail.com> (raw)

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().

Direct replacement is safe here since return value of -errno
is used to check for truncation instead of sizeof(dest).

[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 <azeemshaikh38@gmail.com>
---
 init/version.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/init/version.c b/init/version.c
index f117921811b4..94c96f6fbfe6 100644
--- a/init/version.c
+++ b/init/version.c
@@ -21,10 +21,10 @@ static int __init early_hostname(char *arg)
 {
 	size_t bufsize = sizeof(init_uts_ns.name.nodename);
 	size_t maxlen  = bufsize - 1;
-	size_t arglen;
+	ssize_t arglen;

-	arglen = strlcpy(init_uts_ns.name.nodename, arg, bufsize);
-	if (arglen > maxlen) {
+	arglen = strscpy(init_uts_ns.name.nodename, arg, bufsize);
+	if (arglen < 0) {
 		pr_warn("hostname parameter exceeds %zd characters and will be truncated",
 			maxlen);
 	}
--
2.41.0.255.g8b1d071c50-goog

next             reply	other threads:[~2023-08-30 18:56 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-30 16:08 Azeem Shaikh [this message]
2023-08-30 20:08 ` [PATCH] init/version.c: Replace strlcpy with strscpy Justin Stitt
2023-08-30 21:17 ` Kees Cook
2023-09-15  5:31 ` Kees Cook

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