libelf: Check index_size doesn't overflow in elf_getarsym.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index 7406509e1d248dd222f12ea6ffd1dd54fc56b6dc..fe210abb5244cc52f6f91fda8e3f5fd64b132a89 100644 (file)
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,3 +1,7 @@
+2014-12-15  Mark Wielaard  <mjw@redhat.com>
+
+       * elf_getarsym.c (elf_getarsym): Check index_size doesn't overflow.
+
 2014-12-15  Mark Wielaard  <mjw@redhat.com>
 
        * elf_begin.c (read_long_names): Clear any garbage left in the

diff --git a/libelf/elf_getarsym.c b/libelf/elf_getarsym.c
index ba88aa0aa74c255e8a32e7717686e9b864622779..40633aa87b31b17389e42c8111fae001ce05e493 100644 (file)
--- a/libelf/elf_getarsym.c
+++ b/libelf/elf_getarsym.c
@@ -182,7 +182,8 @@ elf_getarsym (elf, ptr)
       tmpbuf[10] = '\0';
       size_t index_size = atol (tmpbuf);
 
-      if (SARMAG + sizeof (struct ar_hdr) + index_size > elf->maximum_size
+      if (index_size > elf->maximum_size
+         || elf->maximum_size - index_size < SARMAG + sizeof (struct ar_hdr)
 #if SIZE_MAX <= 4294967295U
          || n >= SIZE_MAX / sizeof (Elf_Arsym)
 #endif