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b=vHZkHNV5oUFehXU9H208C3BbvikBh69Map7MNwYhsAz/H+RCy1qVmhkneBJXg6XjJ A4yHeH0HSJKwxa7FLYPOTmemN1bnz5cRIh6lcVsrPvla+TthtasHx5rjtn8C4jsDQk yFp0s7cOZozpGsEjAghDarTvbyerVUBwdhHxnSfOD9KlTBerTrANtAUJssjdzPrjNl EhSD2ZYUuJmNQNe1xBJ/twr+KdnK0XkPc9svL3TfLFPiHpoxVJoRf5gEij63/YgQR2 vdZEieAN5ajY1WQBCTOuo56n3Dt/ZdoRgYqRpXRd3S9XddtW7UgbZC41BpdvWHqRIm XHhHkzQ8KNsPg== Date: Sun, 18 Aug 2024 10:25:30 +0200 From: Alejandro Colomar To: Yafang Shao Cc: akpm@linux-foundation.org, torvalds@linux-foundation.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, Quentin Monnet Subject: Re: [PATCH v7 4/8] bpftool: Ensure task comm is always NUL-terminated Message-ID: References: <20240817025624.13157-1-laoar.shao@gmail.com> <20240817025624.13157-5-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; 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protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Yafang Shao Cc: akpm@linux-foundation.org, torvalds@linux-foundation.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, Quentin Monnet Subject: Re: [PATCH v7 4/8] bpftool: Ensure task comm is always NUL-terminated References: <20240817025624.13157-1-laoar.shao@gmail.com> <20240817025624.13157-5-laoar.shao@gmail.com> MIME-Version: 1.0 In-Reply-To: Hi Yafang, On Sun, Aug 18, 2024 at 10:27:01AM GMT, Yafang Shao wrote: > On Sat, Aug 17, 2024 at 4:39=E2=80=AFPM Alejandro Colomar wrote: > > > > Hi Yafang, > > > > On Sat, Aug 17, 2024 at 10:56:20AM GMT, Yafang Shao wrote: > > > Let's explicitly ensure the destination string is NUL-terminated. Thi= s 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= _iter_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'; > > > > Why doesn't this use strscpy()? >=20 > bpftool is a userspace tool, so strscpy() is only applicable in kernel > code, correct? Ahh, makes sense. LGTM, then. Maybe the closest user-space function to strscpy(9) would be strlcpy(3), but I don't know how old of a glibc you support. strlcpy(3) is currently in POSIX, and supported by both glibc and musl, but that's too recent. Have a lovely day! Alex > -- > Regards > Yafang --=20 --bqpbjdxuldrazcxq Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmbBr/oACgkQnowa+77/ 2zKlWg//bIam9Z2S2oGYdx1Es2yhqgRhsYrxX1OVGAonZ9d+7XaXBTpsSjfcy8AT EqipznL0pk8B0uQ+sagT8w6h0H2StHg59E+gR4M8YKp5s/X6Rhq+aim+k19Qh53S afYHd+jfvzFBe1dXQXm5Pe80X1ncmIcISMqXh/O3ykzqpuPWanKo4torJlbqtXMM yGxL8yJu15D00/cwjEwT9mh7KB9zsmVNyHPiY3aTvtjd0F/tNlP9qvnxgi+81duU ciTElwVWSG14g9TcDFWHkNBarUuBiHe240JQE7ARDPJmPkZrzHo6GcpC4AdydU6Q yvA/1Hp4dCFLoiXspmTWmAyR3Q+Nnn1wetdU555oIpEhYk+dpgAdO1MAYOJ+izdh f71cefEGfG60FG0tkzgwkbpa4xPUaCEi5L/5Voms4yRIoj5eYvmQs0+/N8IM2Fbk HSLIjf+5YiMw0SycNUP0XKFZGJ2MbXU8c+MBM4pTwfl4MFhgVPvI53j0J+5D43x8 AgvgLJ3kp44JOC+FoeCDgraJ7ZD5nasDl1YBaNUS7lCxAAJ80V4CMWzi9kX0YOrG HRB6XOquSAF0pGarE6FLeKCmwKRTcsrDTrVPRgkrHgxt/lYqJJFnaWY1lLKDQViF zUzZFqndM8ocPo0p3o645SxxtVDEvxgJolM+5sdOdjqMKUmKg+U= =rl7R -----END PGP SIGNATURE----- --bqpbjdxuldrazcxq--