[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <d92c26e5-0311-21ce-c52e-6fb81054c100@huawei.com>
Date: Thu, 27 Apr 2023 15:27:25 +0800
From: Yang Jihong <yangjihong1@...wei.com>
To: Adrian Hunter <adrian.hunter@...el.com>, <peterz@...radead.org>,
<mingo@...hat.com>, <acme@...nel.org>, <mark.rutland@....com>,
<alexander.shishkin@...ux.intel.com>, <jolsa@...nel.org>,
<namhyung@...nel.org>, <irogers@...gle.com>, <leo.yan@...aro.org>,
<eranian@...gle.com>, <linux-perf-users@...r.kernel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] perf symbols: Fix return incorrect build_id size in
elf_read_build_id()
Hello,
On 2023/4/27 14:02, Adrian Hunter wrote:
> On 27/04/23 04:28, Yang Jihong wrote:
>> In elf_read_build_id(), if gnu build_id is found, should return the size of
>> the actually copied data. If descsz is greater thanBuild_ID_SIZE,
>> write_buildid data access may occur.
>>
>> Fixes: be96ea8ffa78 ("perf symbols: Fix issue with binaries using 16-bytes buildids (v2)")
>> Reported-by: Will Ochowicz <Will.Ochowicz@...usplc.com>
>> Link: https://lore.kernel.org/lkml/CWLP265MB49702F7BA3D6D8F13E4B1A719C649@CWLP265MB4970.GBRP265.PROD.OUTLOOK.COM/T/
>> Tested-by: Will Ochowicz <Will.Ochowicz@...usplc.com>
>> Signed-off-by: Yang Jihong <yangjihong1@...wei.com>
>
> As an aside, note that the build ID on the ELF file triggering the bug was
> 62363266373430613439613534633666326432323334653665623530396566343938656130663039
> which is 80 ASCII characters, which would have been a 20 byte binary number i.e.
>
> $ echo -en "0000: 62363266373430613439613534633666\n0010: 32643232333465366562353039656634\n0020: 3938656130663039" | xxd -r | od -c -A d
> 0000000 b 6 2 f 7 4 0 a 4 9 a 5 4 c 6 f
> 0000016 2 d 2 2 3 4 e 6 e b 5 0 9 e f 4
> 0000032 9 8 e a 0 f 0 9
> 0000040
>
> So perhaps a mistake in the creation of the build ID on that ELF file.
>
Yes, it may be an error, or it may be that the build-id was specified
when the elf file was created.
I tried ld can specify a build-id larger than 160-bit hexadecimal digits:
$ ld -o test test.o
--build-id=0x62363266373430613439613534633666326432323334653665623530396566343938656130663039
$ readelf -n test
Displaying notes found in: .note.gnu.build-id
Owner Data size Description
GNU 0x00000028 NT_GNU_BUILD_ID (unique build
ID bitstring)
Build ID:
62363266373430613439613534633666326432323334653665623530396566343938656130663039
All in all, it feels like a rare scene :)
> In any case, for the fix:
>
> Acked-by: Adrian Hunter <adrian.hunter@...el.com>
>
Thanks for the acked-by.
Thanks,
Yang
Powered by blists - more mailing lists