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Mon, 25 Oct 2021 01:33:54 -0700 (PDT) Received: from localhost.localdomain ([140.82.17.67]) by smtp.gmail.com with ESMTPSA id p13sm2495694pfo.102.2021.10.25.01.33.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Oct 2021 01:33:53 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, keescook@chromium.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org, viro@zeniv.linux.org.uk, valentin.schneider@arm.com, qiang.zhang@windriver.com, robdclark@chromium.org, christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com, mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com, jgg@ziepe.ca Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, oliver.sang@intel.com, lkp@intel.com, Yafang Shao , Andrii Nakryiko Subject: [PATCH v6 05/12] elfcore: make prpsinfo always get a nul terminated task comm Date: Mon, 25 Oct 2021 08:33:08 +0000 Message-Id: <20211025083315.4752-6-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20211025083315.4752-1-laoar.shao@gmail.com> References: <20211025083315.4752-1-laoar.shao@gmail.com> MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 3BBACD000097 X-Stat-Signature: i3dyf1oy395kgzfg3u7gnpga69sy7o8t Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="fW/gHi2S"; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf15.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.215.179 as permitted sender) smtp.mailfrom=laoar.shao@gmail.com X-HE-Tag: 1635150829-520931 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: kernel test robot reported a -Wstringop-truncation warning after I extend task comm from 16 to 24. Below is the detailed warning: fs/binfmt_elf.c: In function 'fill_psinfo.isra': >> fs/binfmt_elf.c:1575:9: warning: 'strncpy' output may be truncated copying 16 bytes from a string of length 23 [-Wstringop-truncation] 1575 | strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This patch can fix this warning. Replacing strncpy() with strscpy_pad() can avoid this warning. This patch also replace the hard-coded 16 with TASK_COMM_LEN to make it more compatible with task comm size change. I also verfied if it still work well when I extend the comm size to 24. struct elf_prpsinfo is used to dump the task information in userspace coredump or kernel vmcore. Below is the verfication of vmcore, crash> ps PID PPID CPU TASK ST %MEM VSZ RSS COMM 0 0 0 ffffffff9d21a940 RU 0.0 0 0 [swapper/0] > 0 0 1 ffffa09e40f85e80 RU 0.0 0 0 [swapper/1] > 0 0 2 ffffa09e40f81f80 RU 0.0 0 0 [swapper/2] > 0 0 3 ffffa09e40f83f00 RU 0.0 0 0 [swapper/3] > 0 0 4 ffffa09e40f80000 RU 0.0 0 0 [swapper/4] > 0 0 5 ffffa09e40f89f80 RU 0.0 0 0 [swapper/5] 0 0 6 ffffa09e40f8bf00 RU 0.0 0 0 [swapper/6] > 0 0 7 ffffa09e40f88000 RU 0.0 0 0 [swapper/7] > 0 0 8 ffffa09e40f8de80 RU 0.0 0 0 [swapper/8] > 0 0 9 ffffa09e40f95e80 RU 0.0 0 0 [swapper/9] > 0 0 10 ffffa09e40f91f80 RU 0.0 0 0 [swapper/10] > 0 0 11 ffffa09e40f93f00 RU 0.0 0 0 [swapper/11] > 0 0 12 ffffa09e40f90000 RU 0.0 0 0 [swapper/12] > 0 0 13 ffffa09e40f9bf00 RU 0.0 0 0 [swapper/13] > 0 0 14 ffffa09e40f98000 RU 0.0 0 0 [swapper/14] > 0 0 15 ffffa09e40f9de80 RU 0.0 0 0 [swapper/15] It works well as expected. Reported-by: kernel test robot Signed-off-by: Yafang Shao Cc: Mathieu Desnoyers Cc: Arnaldo Carvalho de Melo Cc: Andrii Nakryiko Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Al Viro Cc: Kees Cook Cc: Petr Mladek --- fs/binfmt_elf.c | 2 +- include/linux/elfcore-compat.h | 3 ++- include/linux/elfcore.h | 4 ++-- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index a813b70f594e..a4ba79fce2a9 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1572,7 +1572,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p, SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); rcu_read_unlock(); - strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); + strscpy_pad(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); return 0; } diff --git a/include/linux/elfcore-compat.h b/include/linux/elfcore-compat.h index e272c3d452ce..afa0eb45196b 100644 --- a/include/linux/elfcore-compat.h +++ b/include/linux/elfcore-compat.h @@ -5,6 +5,7 @@ #include #include #include +#include /* * Make sure these layouts match the linux/elfcore.h native definitions. @@ -43,7 +44,7 @@ struct compat_elf_prpsinfo __compat_uid_t pr_uid; __compat_gid_t pr_gid; compat_pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid; - char pr_fname[16]; + char pr_fname[TASK_COMM_LEN]; char pr_psargs[ELF_PRARGSZ]; }; diff --git a/include/linux/elfcore.h b/include/linux/elfcore.h index 2aaa15779d50..8d79cd58b09a 100644 --- a/include/linux/elfcore.h +++ b/include/linux/elfcore.h @@ -65,8 +65,8 @@ struct elf_prpsinfo __kernel_gid_t pr_gid; pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid; /* Lots missing */ - char pr_fname[16]; /* filename of executable */ - char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */ + char pr_fname[TASK_COMM_LEN]; /* filename of executable */ + char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */ }; static inline void elf_core_copy_regs(elf_gregset_t *elfregs, struct pt_regs *regs)