Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Romain Perier <romain.perier@gmail.com>
To:     Kees Cook <keescook@chromium.org>,
        kernel-hardening@lists.openwall.com,
        Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Romain Perier <romain.perier@gmail.com>,
        linux-m68k@lists.linux-m68k.org, linux-kernel@vger.kernel.org
Subject: [PATCH 09/20] m68k/atari: Manual replacement of the deprecated strlcpy() with return values
Date:   Mon, 22 Feb 2021 16:12:20 +0100
Message-Id: <20210222151231.22572-10-romain.perier@gmail.com>
In-Reply-To: <20210222151231.22572-1-romain.perier@gmail.com>
References: <20210222151231.22572-1-romain.perier@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The strlcpy() reads the entire source buffer first, it is dangerous if
the source buffer lenght is unbounded or possibility non NULL-terminated.
It can lead to linear read overflows, crashes, etc...

As recommended in the deprecated interfaces [1], it should be replaced
by strscpy.

This commit replaces all calls to strlcpy that handle the return values
by the corresponding strscpy calls with new handling of the return
values (as it is quite different between the two functions).

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy

Signed-off-by: Romain Perier <romain.perier@gmail.com>
---
 arch/m68k/emu/natfeat.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/m68k/emu/natfeat.c b/arch/m68k/emu/natfeat.c
index 71b78ecee75c..fbb3454d3c6a 100644
--- a/arch/m68k/emu/natfeat.c
+++ b/arch/m68k/emu/natfeat.c
@@ -41,10 +41,10 @@ long nf_get_id(const char *feature_name)
 {
 	/* feature_name may be in vmalloc()ed memory, so make a copy */
 	char name_copy[32];
-	size_t n;
+	ssize_t n;
 
-	n = strlcpy(name_copy, feature_name, sizeof(name_copy));
-	if (n >= sizeof(name_copy))
+	n = strscpy(name_copy, feature_name, sizeof(name_copy));
+	if (n == -E2BIG)
 		return 0;
 
 	return nf_get_id_phys(virt_to_phys(name_copy));