Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8;
MIME-Version: 1.0
References: <20230907210533.3712979-1-irogers@google.com>
In-Reply-To: <20230907210533.3712979-1-irogers@google.com>
From:   Ian Rogers <irogers@google.com>
Date:   Fri, 6 Oct 2023 08:29:47 -0700
Message-ID: <CAP-5=fVaK2hhBTX4=zKX5Dft36RurctYEtGzsdUp6XKsjHguMw@mail.gmail.com>
Subject: Re: [PATCH v1] perf parse-events: Avoid erange from hex numbers
To:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Rob Herring <robh@kernel.org>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On Thu, Sep 7, 2023 at 2:05=E2=80=AFPM Ian Rogers <irogers@google.com> wrot=
e:
>
> We specify that a "num_hex" comprises 1 or more digits, however, that
> allows strtoull to fail with ERANGE. Limit the number of hex digits to
> being between 1 and 16.
>
> Before:
> ```
> $ perf stat -e 'cpu/rE7574c47490475745/' true
> perf: util/parse-events.c:215: fix_raw: Assertion `errno =3D=3D 0' failed=
.
> Aborted (core dumped)
> ```
>
> After:
> ```
> $ perf stat -e 'cpu/rE7574c47490475745/' true
> event syntax error: 'cpu/rE7574c47490475745/'
>                          \___ Bad event or PMU
>
> Unable to find PMU or event on a PMU of 'cpu'
>
> Initial error:
> event syntax error: 'cpu/rE7574c47490475745/'
>                          \___ unknown term 'rE7574c47490475745' for pmu '=
cpu'
>
> valid terms: event,pc,edge,offcore_rsp,ldlat,inv,umask,frontend,cmask,con=
fig,config1,config2,config3,name,period,percore,metric-id
> Run 'perf list' for a list of valid events
>
>  Usage: perf stat [<options>] [<command>]
>
>     -e, --event <event>   event selector. use 'perf list' to list availab=
le events
> ```
>
> Issue found through fuzz testing.
>
> Signed-off-by: Ian Rogers <irogers@google.com>

Hi, would be nice to land this.

Thanks!
Ian

> ---
>  tools/perf/util/parse-events.l | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-event=
s.l
> index 4ef4b6f171a0..f7df52b22c39 100644
> --- a/tools/perf/util/parse-events.l
> +++ b/tools/perf/util/parse-events.l
> @@ -156,8 +156,8 @@ event_pmu   [^,{}/]+[/][^/]*[/][^,{}/]*
>  event          [^,{}/]+
>
>  num_dec                [0-9]+
> -num_hex                0x[a-fA-F0-9]+
> -num_raw_hex    [a-fA-F0-9]+
> +num_hex                0x[a-fA-F0-9]{1,16}
> +num_raw_hex    [a-fA-F0-9]{1,16}
>  name           [a-zA-Z_*?\[\]][a-zA-Z0-9_*?.\[\]!\-]*
>  name_tag       [\'][a-zA-Z_*?\[\]][a-zA-Z0-9_*?\-,\.\[\]:=3D]*[\']
>  name_minus     [a-zA-Z_*?][a-zA-Z0-9\-_*?.:]*
> --
> 2.42.0.283.g2d96d420d3-goog
>