Commit 7ad74b41 authored by Mitchell Krome's avatar Mitchell Krome Committed by Arnaldo Carvalho de Melo
Browse files

perf symbols: Fix use after free in filename__read_build_id 



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: default avatarMitchell Krome <mitchellkrome@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20141216021612.GA7199@mitchell


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 91529834

tools/perf/util/symbol-minimal.c

+6 −2
Original line number Diff line number Diff line
@@ -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);

			if (fread(buf, buf_size, 1, fp) != 1)

				goto out_free;
@@ -178,6 +180,7 @@ 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);
@@ -189,12 +192,13 @@ 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);

			if (fread(buf, buf_size, 1, fp) != 1)

				goto out_free;

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