Messages in this thread | | | Date | Tue, 16 Dec 2014 16:35:23 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH] perf tool: Fix use after free in filename__read_build_id |
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On Tue, Dec 16, 2014 at 12:16:12PM +1000, Mitchell Krome wrote: > In filename__read_build_id, phdr points to memory in buf, which gets realloced > before a call to fseek that uses phdr->p_offset. This change stores the value > of p_offset before buf is realloced, so the fseek can use the value safely. > > Signed-off-by: Mitchell Krome <mitchellkrome@gmail.com> > --- > tools/perf/util/symbol-minimal.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c > index fa585c6..d7efb03 100644 > --- a/tools/perf/util/symbol-minimal.c > +++ b/tools/perf/util/symbol-minimal.c > @@ -129,6 +129,7 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) > > for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { > void *tmp; > + long offset; > > if (need_swap) { > phdr->p_type = bswap_32(phdr->p_type); > @@ -140,12 +141,13 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) > continue; > > buf_size = phdr->p_filesz; > + offset = phdr->p_offset; > tmp = realloc(buf, buf_size); > if (tmp == NULL) > goto out_free; > > buf = tmp; > - fseek(fp, phdr->p_offset, SEEK_SET); > + fseek(fp, offset, SEEK_SET);
so the concern is that the realloc buf_size will be smaller than the 'buf' offset of phdr->p_offset value, right? Anyway:
Acked-by: Jiri Olsa <jolsa@kernel.org>
jirka
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