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[PATCH 1/3] libelf: Fix unbounded stack usage in elf_getarsym for !ALLOW_UNALIGNED case.
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Sun, 31 May 2015 21:05:42 +0200
- Subject: [PATCH 1/3] libelf: Fix unbounded stack usage in elf_getarsym for !ALLOW_UNALIGNED case.
The number of entries in the index can be large, don't use alloca to
read in temporary data, use malloc (which is freed after out).
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
libelf/ChangeLog | 5 +++++
libelf/elf_getarsym.c | 10 +++++++++-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index b749c08..4fd3f9f 100644
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,3 +1,8 @@
+2015-05-31 Mark Wielaard <mjw@redhat.com>
+
+ * elf_getarsym.c (elf_getarsym): Allocate temporary file_date with
+ malloc, not alloca also in !ALLOW_UNALIGNED case.
+
2015-05-30 Mark Wielaard <mjw@redhat.com>
* gelf_xlate.c (elf_cvt_Byte): Only call memmove with non-zero size.
diff --git a/libelf/elf_getarsym.c b/libelf/elf_getarsym.c
index 4f2080a..8324244 100644
--- a/libelf/elf_getarsym.c
+++ b/libelf/elf_getarsym.c
@@ -255,7 +255,15 @@ elf_getarsym (elf, ptr)
file_data = (void *) (elf->map_address + off);
if (!ALLOW_UNALIGNED
&& ((uintptr_t) file_data & -(uintptr_t) n) != 0)
- file_data = memcpy (alloca (sz), elf->map_address + off, sz);
+ {
+ temp_data = malloc (sz);
+ if (unlikely (temp_data == NULL))
+ {
+ __libelf_seterrno (ELF_E_NOMEM);
+ goto out;
+ }
+ file_data = memcpy (temp_data, elf->map_address + off, sz);
+ }
str_data = (char *) (elf->map_address + off + sz);
}
--
2.4.2