From: German Gomez <german.gomez@arm.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
kajoljain <kjain@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
John Garry <john.garry@huawei.com>, Will Deacon <will@kernel.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Leo Yan <leo.yan@linaro.org>, Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH v1 1/4] perf tools: Prevent out-of-bounds access to registers
Date: Fri, 10 Dec 2021 15:28:56 +0000 [thread overview]
Message-ID: <42c6ea29-5904-bb8b-d9c6-a0516c3a564f@arm.com> (raw)
In-Reply-To: <YbNYUC1poqzrWynP@kernel.org>
On 10/12/2021 13:38, Arnaldo Carvalho de Melo wrote:
> Em Fri, Dec 10, 2021 at 02:47:49PM +0530, kajoljain escreveu:
>>
>> On 12/1/21 6:03 PM, German Gomez wrote:
>>> The size of the cache of register values is arch-dependant
>>> (PERF_REGS_MAX). This has the potential of causing an out-of-bounds
>>> access in the function "perf_reg_value" if the local architecture
>>> contains less registers than the one the perf.data file was recorded on.
>>>
>>> Since the maximum number of registers is bound by the bitmask "u64
>>> cache_mask", and the size of the cache when running under x86 systems is
>>> 64 already, fix the size to 64 and add a range-check to the function
>>> "perf_reg_value" to prevent out-of-bounds access.
>>>
>> Patch looks good to me.
>>
>> Reviewed-by: Kajol Jain<kjain@linux.ibm.com>
> Thanks, applied.
>
> - Arnaldo
Thanks Arnaldo, and the rest for the review.
I did send a v2 of this patch afterwards. The only difference was to
give credit to the reporter in the commit message with:
Reported-by: Alexandre Truong <alexandre.truong@arm.com>
Thanks,
German
>
>> Thanks,
>> Kajol Jain
>>
>>> Signed-off-by: German Gomez <german.gomez@arm.com>
>>> ---
>>> tools/perf/util/event.h | 5 ++++-
>>> tools/perf/util/perf_regs.c | 3 +++
>>> 2 files changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
>>> index 95ffed663..c59331eea 100644
>>> --- a/tools/perf/util/event.h
>>> +++ b/tools/perf/util/event.h
>>> @@ -44,13 +44,16 @@ struct perf_event_attr;
>>> /* perf sample has 16 bits size limit */
>>> #define PERF_SAMPLE_MAX_SIZE (1 << 16)
>>>
>>> +/* number of register is bound by the number of bits in regs_dump::mask (64) */
>>> +#define PERF_SAMPLE_REGS_CACHE_SIZE (8 * sizeof(u64))
>>> +
>>> struct regs_dump {
>>> u64 abi;
>>> u64 mask;
>>> u64 *regs;
>>>
>>> /* Cached values/mask filled by first register access. */
>>> - u64 cache_regs[PERF_REGS_MAX];
>>> + u64 cache_regs[PERF_SAMPLE_REGS_CACHE_SIZE];
>>> u64 cache_mask;
>>> };
>>>
>>> diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
>>> index 5ee47ae15..06a7461ba 100644
>>> --- a/tools/perf/util/perf_regs.c
>>> +++ b/tools/perf/util/perf_regs.c
>>> @@ -25,6 +25,9 @@ int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
>>> int i, idx = 0;
>>> u64 mask = regs->mask;
>>>
>>> + if ((u64)id >= PERF_SAMPLE_REGS_CACHE_SIZE)
>>> + return -EINVAL;
>>> +
>>> if (regs->cache_mask & (1ULL << id))
>>> goto out;
>>>
>>>
next prev parent reply other threads:[~2021-12-10 15:29 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-01 12:33 [PATCH v1 0/4] Support register names from all architectures German Gomez
2021-12-01 12:33 ` [PATCH v1 1/4] perf tools: Prevent out-of-bounds access to registers German Gomez
2021-12-08 21:35 ` Jiri Olsa
2021-12-10 9:17 ` kajoljain
2021-12-10 13:38 ` Arnaldo Carvalho de Melo
2021-12-10 15:28 ` German Gomez [this message]
2021-12-10 16:19 ` Arnaldo Carvalho de Melo
2021-12-01 12:33 ` [PATCH v1 2/4] perf script: Add "struct machine" parameter to process_event callback German Gomez
2021-12-02 16:03 ` Athira Rajeev
2021-12-03 12:00 ` German Gomez
2021-12-13 18:22 ` Arnaldo Carvalho de Melo
2021-12-13 18:31 ` German Gomez
2021-12-13 19:59 ` Arnaldo Carvalho de Melo
2021-12-01 12:33 ` [PATCH v1 3/4] perf tools: Crete header files with register names German Gomez
2021-12-01 12:33 ` [PATCH v1 4/4] perf tools: Support register names from all architectures German Gomez
2021-12-03 9:38 ` German Gomez
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