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Thu, 12 Sep 2024 19:20:53 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20240828030321.20688-1-laoar.shao@gmail.com> <20240828030321.20688-5-laoar.shao@gmail.com> In-Reply-To: From: Yafang Shao Date: Fri, 13 Sep 2024 10:20:16 +0800 Message-ID: Subject: Re: [PATCH v8 4/8] bpftool: Ensure task comm is always NUL-terminated To: Justin Stitt Cc: akpm@linux-foundation.org, torvalds@linux-foundation.org, alx@kernel.org, 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, Quentin Monnet Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, Sep 13, 2024 at 5:14=E2=80=AFAM Justin Stitt wrote: > > Hi, > > On Wed, Aug 28, 2024 at 11:03:17AM GMT, Yafang Shao wrote: > > Let's explicitly ensure the destination string is NUL-terminated. This = way, > > it won't be affected by changes to the source string. > > > > Signed-off-by: Yafang Shao > > Reviewed-by: Quentin Monnet > > --- > > tools/bpf/bpftool/pids.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c > > index 9b898571b49e..23f488cf1740 100644 > > --- a/tools/bpf/bpftool/pids.c > > +++ b/tools/bpf/bpftool/pids.c > > @@ -54,6 +54,7 @@ static void add_ref(struct hashmap *map, struct pid_i= ter_entry *e) > > ref =3D &refs->refs[refs->ref_cnt]; > > ref->pid =3D e->pid; > > memcpy(ref->comm, e->comm, sizeof(ref->comm)); > > + ref->comm[sizeof(ref->comm) - 1] =3D '\0'; > > ... > > > refs->ref_cnt++; > > > > return; > > @@ -77,6 +78,7 @@ static void add_ref(struct hashmap *map, struct pid_i= ter_entry *e) > > ref =3D &refs->refs[0]; > > ref->pid =3D e->pid; > > memcpy(ref->comm, e->comm, sizeof(ref->comm)); > > + ref->comm[sizeof(ref->comm) - 1] =3D '\0'; > > Excuse my ignorance, do we not have a strscpy() equivalent usable in bpf > code? To my knowledge, there is no direct equivalent of the standard strcpy() function available in bpftool or libbpf code. --=20 Regards Yafang