If we call elf_section_by_name() with a truncated elf image (ie: the file
header indicates that the section headers are placed past the end of the
file), elf_strptr() causes a segfault within libelf.

Avoid this by checking that we can access the section string table
properly.

Should really be fixed in libelf/elfutils.

Signed-off-by: Cody P Schafer <c...@linux.vnet.ibm.com>
---
 tools/perf/util/symbol-elf.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index a2e994e..a9a194d 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -129,6 +129,10 @@ static Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr 
*ep,
        Elf_Scn *sec = NULL;
        size_t cnt = 1;
 
+       /* Elf is corrupted/truncated, avoid calling elf_strptr. */
+       if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
+               return NULL;
+
        while ((sec = elf_nextscn(elf, sec)) != NULL) {
                char *str;
 
-- 
1.7.11.3

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