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Message-ID: <ZExzXy5J+CAjOD81@kernel.org>
Date: Fri, 28 Apr 2023 22:31:11 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Adrian Hunter <adrian.hunter@...el.com>
Cc: Yang Jihong <yangjihong1@...wei.com>, peterz@...radead.org,
mingo@...hat.com, 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()
Em Thu, Apr 27, 2023 at 09:02:06AM +0300, Adrian Hunter escreveu:
> 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.
>
> In any case, for the fix:
>
> Acked-by: Adrian Hunter <adrian.hunter@...el.com>
Thanks, applied.
- Arnaldo
> > ---
> > tools/perf/util/symbol-elf.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> > index 41882ae8452e..059f88eca630 100644
> > --- a/tools/perf/util/symbol-elf.c
> > +++ b/tools/perf/util/symbol-elf.c
> > @@ -903,7 +903,7 @@ static int elf_read_build_id(Elf *elf, void *bf, size_t size)
> > size_t sz = min(size, descsz);
> > memcpy(bf, ptr, sz);
> > memset(bf + sz, 0, size - sz);
> > - err = descsz;
> > + err = sz;
> > break;
> > }
> > }
>
--
- Arnaldo
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