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b=mYzQuqq14/wTRRzzUwsG17Ab+8tgoUHpySPnl84Mr25NNzcLhEp7Tq87twOltFKtA dLD4dH0S9ylQ5twpfaifjPBB9F9nLw9N+znijKLYLcOnWkObGODYTAZeChhNq2O2Ca IQI8NCRh7J2BZ5sI7mVRJjsoRWd+WGQFkSSMno0hv8VCeplcjuV9ER78Y79IneS3ww A/5asZFiMwgLRWg3CnX7bPRgzhBlLJJ299YG81hHCGwYVIYI6Vtka99WENBzIlbtj9 RDwPxtwzVpVgN2qYy6WEMTlYIhf+ZUrM+RRJ4JaWwLGuxFHxYcI/kP7k045W27PJnL 9gvSnUTnaD3zQ== From: Christian Brauner To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , Jann Horn , Josef Bacik , Chris Mason , Jeff Layton , NeilBrown , Eric Dumazet , Thomas Gleixner , Al Viro , Jonathan Corbet , Christoph Hellwig , Greg Kroah-Hartman , Joel Granados , Kees Cook , Jan Kara , Jan Kara , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-um@lists.infradead.org, linux-wireless@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, ntfs3@lists.linux.dev, platform-driver-x86@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, netfilter-devel@vger.kernel.org, dri-devel@lists.freedesktop.org, ibm-acpi-devel@lists.sourceforge.net, jfs-discussion@lists.sourceforge.net, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-cifs@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, sparclinux@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-doc@vger.kernel.org, linux-serial@vger.kernel.org, linux-atm-general@lists.sourceforge.net, Takashi Iwai , linux-input@vger.kernel.org, linux-raid@vger.kernel.org, linux-ext4@vger.kernel.org, linux-modules@vger.kernel.org, linux-debuggers@vger.kernel.org, "Christian Brauner (Amutable)" , Chuck Lever , stable@vger.kernel.org Subject: [PATCH v2 27/51] um: NUL-terminate what is written to /proc/exitcode Date: Wed, 4 Nov 2026 18:47:13 +0100 Message-ID: <20261104-work-procfs-bugfixes-v2-27-bbf7d5546809@kernel.org> In-Reply-To: <20261104-work-procfs-bugfixes-v2-0-bbf7d5546809@kernel.org> References: <20261104-work-procfs-bugfixes-v2-0-bbf7d5546809@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; 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So "echo -n 5" parses whatever the stack held after the '5', and a write of seven bytes or more reads past the end of buf. Terminate the copy. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner (Amutable) --- arch/um/kernel/exitcode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/um/kernel/exitcode.c b/arch/um/kernel/exitcode.c index 43edc2aa57e4..0230354f4812 100644 --- a/arch/um/kernel/exitcode.c +++ b/arch/um/kernel/exitcode.c @@ -43,9 +43,10 @@ static ssize_t exitcode_proc_write(struct file *file, size_t size; int tmp; - size = min(count, sizeof(buf)); + size = min(count, sizeof(buf) - 1); if (copy_from_user(buf, buffer, size)) return -EFAULT; + buf[size] = '\0'; tmp = simple_strtol(buf, &end, 0); if ((*end != '\0') && !isspace(*end)) -- 2.53.0