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Hallyn" Subject: Re: [PATCH v8 1/8] Get rid of __get_task_comm() Message-ID: References: <20240828030321.20688-1-laoar.shao@gmail.com> <20240828030321.20688-2-laoar.shao@gmail.com> <7839453E-CA06-430A-A198-92EB906F94D9@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="utmrbzzw4vz6dwo3" Content-Disposition: inline In-Reply-To: <7839453E-CA06-430A-A198-92EB906F94D9@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 5A39F18002B X-Stat-Signature: mjmsqfgosj7qe74zbmat8je44wtnqt4c X-HE-Tag: 1724857756-106939 X-HE-Meta: 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 P4S8e5R/ DV+OXIom66Mpk7HDnHkBp59p2S9snZH/Yk+OHnQukrkpu99kNjumwcdEdKmtzL7JcxKFvDFjwbk8q6fdQmOSsgT8o7AIlIvVzYKb7vpMLhie3rEB3S8bDci5Vj62Ejh6dfX9+oq5gfYf8VI4wjftfYOKaBwIlm21Crm6hwfvT9+cQA8oG92PuA+h9oZSDldid2Pg39YP3joCgIbQr2KI00iVXO0oRHgXOHIOu+gwLme3qR9tO1w4XdTfYSaV9oQCKYvMsN8L0wWBdRN4Xmo0bN5MsgZgHxIkhtU63WyA1fPftd4htMP6E8xW4J+Wt1nhm142Su9QkinpdM9MRIih6jjB37Vwikp/teZCZjeG8AidFxhLhro+frAdeCC1zRnQ+GFyXVjAxqSh2q4IUhMykjUgNi0Zl/TBivniVxJLiWrLB1Rw3sZts2CkyE/Cp1MY0KB3M9ACnXgT3LV0YaGjBBqNvWZtNU6yC4vsTVtYsCEwbXpCyuNNwPyzmrWG4hs1bQQ2zYMjOFy3J2IrE5kOYYgJ+Id/hDtKHfRjg4b4EWYsQ/T3fxZJ8GCZjOnrkuVOLdD62pdMq9PqHpoO7J2QHDvn1lANuo8InKTg5jLr2tMh+jj8= 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: List-Subscribe: List-Unsubscribe: --utmrbzzw4vz6dwo3 Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Kees Cook Cc: Yafang Shao , 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, Alexander Viro , Christian Brauner , Jan Kara , Kees Cook , Matus Jokay , "Serge E. Hallyn" Subject: Re: [PATCH v8 1/8] Get rid of __get_task_comm() References: <20240828030321.20688-1-laoar.shao@gmail.com> <20240828030321.20688-2-laoar.shao@gmail.com> <7839453E-CA06-430A-A198-92EB906F94D9@kernel.org> MIME-Version: 1.0 In-Reply-To: <7839453E-CA06-430A-A198-92EB906F94D9@kernel.org> Hi Kees, On Wed, Aug 28, 2024 at 06:48:39AM GMT, Kees Cook wrote: [...] > >Thank you for your suggestion. How does the following commit log look > >to you? Does it meet your expectations? > > > > string: Use ARRAY_SIZE() in strscpy() > > > > We can use ARRAY_SIZE() instead to clarify that they are regular cha= racters. > > > > Co-developed-by: Alejandro Colomar > > Signed-off-by: Alejandro Colomar > > Signed-off-by: Yafang Shao > > > >diff --git a/arch/um/include/shared/user.h b/arch/um/include/shared/user= =2Eh > >index bbab79c0c074..07216996e3a9 100644 > >--- a/arch/um/include/shared/user.h > >+++ b/arch/um/include/shared/user.h > >@@ -14,7 +14,7 @@ > > * copying too much infrastructure for my taste, so userspace files > > * get less checking than kernel files. > > */ > >-#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) > >+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]) + __must_be_array(x)) > > > > /* This is to get size_t and NULL */ > > #ifndef __UM_HOST__ > >@@ -60,7 +60,7 @@ static inline void print_hex_dump(const char *level, > >const char *prefix_str, > > extern int in_aton(char *str); > > extern size_t strlcat(char *, const char *, size_t); > > extern size_t sized_strscpy(char *, const char *, size_t); > >-#define strscpy(dst, src) sized_strscpy(dst, src, sizeof(dst)) > >+#define strscpy(dst, src) sized_strscpy(dst, src, ARRAY_SIZE(dst)) >=20 > Uh, but why? strscpy() copies bytes, not array elements. Using sizeof() i= s already correct and using ARRAY_SIZE() could lead to unexpectedly small c= ounts (in admittedly odd situations). >=20 > What is the problem you're trying to solve here? I suggested that here: There, you'll find the rationale (and also for avoiding the _pad calls where not necessary --I ignore if it's necessary here--). Have a lovely day! Alex >=20 > -Kees >=20 > --=20 > Kees Cook --=20 --utmrbzzw4vz6dwo3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE6jqH8KTroDDkXfJAnowa+77/2zIFAmbPPZQACgkQnowa+77/ 2zLbhBAAlmo97hSALOMFZhNvjtiifi8OS3Fmi4WyEj8YDnX4pfh+3drVAhe2b44u nrvjsBMEM1AHDiXa+gp3sUheR3N1kFuX1oyxlPsb9crUH3IfubT4kG0tQ6qLqE8M Tv0OfPWGdqeGMgvvTEiQVb4xcs/OMT5T4hVdwAtws8Lw0f1ofW5uE5Vlhu5GUXUB Mbz0DBwkRwBtEmnOCDeZE8zBL8ifIc7k5lQ7Kp1hr4gg/89oLXSABSSxtkyx2U20 8Q1u2OXUiGq4J1BPkNs/5REFb+DJ5bpor7fMecfxoIKms1HXU4w3BjLO6x0ijCTc cKtZD6eMdpBVNhzXDsJpwMEePaKmJ8k9M4XEVFzBGvdKZ7nAx2meA0rmRssG8tVN PkNk/kswZIw0qi+m7Lo5uoWOoyKt/s3/UxyUehrIs2k836Zxc9gNdXzX3V9l/R7l KStxOPruRK2CjPtIE+OBeCpkVxVpFnNhyOVRADi9sWf4ztjwoo8acuXuDNjBDRoP ggNzOacqXIv8N0Ly6pn+01O6jUg5VNLndq9hOMveyamHwRAZVTDiJMh2xmJqBW41 jIckyXwpnHly1Ag/DEWDiLlgjL0KTcqLGn3Y3oG4jd6PKxqUpxZHGw5UvLPq4QOk Oy6ZjqF9XGRi8kCgo0hGVLIKxJX7RfAZydaWmAjQVouEODj3TvU= =wcL8 -----END PGP SIGNATURE----- --utmrbzzw4vz6dwo3--