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Mon, 07 Oct 2024 07:49:31 -0700 (PDT) Received: from localhost.localdomain ([223.104.210.43]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-71df0d7cf82sm4466432b3a.200.2024.10.07.07.49.22 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Oct 2024 07:49:30 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, keescook@chromium.org, alx@kernel.org, justinstitt@google.com, ebiederm@xmission.com, alexei.starovoitov@gmail.com, rostedt@goodmis.org, catalin.marinas@arm.com, penguin-kernel@i-love.sakura.ne.jp, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, audit@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, Yafang Shao Subject: [PATCH v9 0/7] Improve the copy of task comm Date: Mon, 7 Oct 2024 22:49:04 +0800 Message-Id: <20241007144911.27693-1-laoar.shao@gmail.com> X-Mailer: git-send-email 2.30.1 (Apple Git-130) Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Using {memcpy,strncpy,strcpy,kstrdup} to copy the task comm relies on the length of task comm. Changes in the task comm could result in a destination string that is overflow. Therefore, we should explicitly ensure the destination string is always NUL-terminated, regardless of the task comm. This approach will facilitate future extensions to the task comm. As suggested by Linus [0], we can identify all relevant code with the following git grep command: git grep 'memcpy.*->comm\>' git grep 'kstrdup.*->comm\>' git grep 'strncpy.*->comm\>' git grep 'strcpy.*->comm\>' PATCH #2~#4: memcpy PATCH #5~#6: kstrdup PATCH #7: strcpy Please note that strncpy() is not included in this series as it is being tracked by another effort. [1] task_lock() is removed from get_task_comm() as it is unnecessary. Suggested-by: Linus Torvalds Link: https://lore.kernel.org/all/CAHk-=wjAmmHUg6vho1KjzQi2=psR30+CogFd4aXrThr2gsiS4g@mail.gmail.com/ [0] Changes: v8->v9: - Keep the BUILD_BUG_ON() in get_task_comm() (Kees) - Keep strscpy_pad() in get_task_comm() (Kees) - Replace more strcpy() with strscpy() in drivers/gpu/drm/i915/i915_gpu_error.c (Justin) - Fix typos and commit improvement in patch #5 (Andy) - Drop the change in net as it was fixed by b19f69a95830 ("net/ipv6: replace deprecated strcpy with strscpy") v7->v8: https://lore.kernel.org/all/20240828030321.20688-1-laoar.shao@gmail.com/ - Avoid '+1' and '-1' in string copy. (Alejandro) v6->v7: https://lore.kernel.org/all/20240817025624.13157-1-laoar.shao@gmail.com/ - Improve the comment (Alejandro) - Drop strncpy as it is being tracked by another effort (Justin) https://github.com/KSPP/linux/issues/90 [1] v5->v6: https://lore.kernel.org/linux-mm/20240812022933.69850-1-laoar.shao@gmail.com/ - Get rid of __get_task_comm() (Linus) - Use ARRAY_SIZE() in get_task_comm() (Alejandro) v4->v5: https://lore.kernel.org/all/20240804075619.20804-1-laoar.shao@gmail.com/ - Drop changes in the mm/kmemleak.c as it was fixed by commit 0b84780134fb ("mm/kmemleak: replace strncpy() with strscpy()") - Drop changes in kernel/tsacct.c as it was fixed by commit 0fe2356434e ("tsacct: replace strncpy() with strscpy()") v3->v4: https://lore.kernel.org/linux-mm/20240729023719.1933-1-laoar.shao@gmail.com/ - Rename __kstrndup() to __kmemdup_nul() and define it inside mm/util.c (Matthew) - Remove unused local variable (Simon) v2->v3: https://lore.kernel.org/all/20240621022959.9124-1-laoar.shao@gmail.com/ - Deduplicate code around kstrdup (Andrew) - Add commit log for dropping task_lock (Catalin) v1->v2: https://lore.kernel.org/bpf/20240613023044.45873-1-laoar.shao@gmail.com/ - Add comment for dropping task_lock() in __get_task_comm() (Alexei) - Drop changes in trace event (Steven) - Fix comment on task comm (Matus) v1: https://lore.kernel.org/all/20240602023754.25443-1-laoar.shao@gmail.com/ Yafang Shao (7): Get rid of __get_task_comm() auditsc: Replace memcpy() with strscpy() security: Replace memcpy() with get_task_comm() bpftool: Ensure task comm is always NUL-terminated mm/util: Fix possible race condition in kstrdup() mm/util: Deduplicate code in {kstrdup,kstrndup,kmemdup_nul} drm: Replace strcpy() with strscpy() drivers/gpu/drm/drm_framebuffer.c | 2 +- drivers/gpu/drm/i915/i915_gpu_error.c | 6 +-- fs/exec.c | 10 ----- fs/proc/array.c | 2 +- include/linux/sched.h | 28 +++++++++--- kernel/auditsc.c | 6 +-- kernel/kthread.c | 2 +- mm/util.c | 62 ++++++++++++--------------- security/lsm_audit.c | 4 +- security/selinux/selinuxfs.c | 2 +- tools/bpf/bpftool/pids.c | 2 + 11 files changed, 63 insertions(+), 63 deletions(-)