[PATCH] libdw: Check DIE address fall inside the CU before reading abbrev code.

[PATCH] libdw: Check DIE address fall inside the CU before reading abbrev code.

[Mark Wielaard]

The afl fuzzer found a case where we tried reading an uleb for the DIE
abbrev code without properly checking the DIE address is inside the CU.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 libdw/ChangeLog | 4 ++++
 libdw/libdwP.h  | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index b000492..b569393 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,5 +1,9 @@
 2018-06-06  Mark Wielaard  <mark@klomp.org>
 
+	* libdwP.h (__libdw_dieabbrev): Check DIE addr falls in cu.
+
+2018-06-06  Mark Wielaard  <mark@klomp.org>
+
 	* dwarf_getlocation_die.c (dwarf_getlocation_die): Check offset
 	falls inside cu data.
 
diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index 1c8dd0d..3d8e145 100644
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -653,7 +653,7 @@ __libdw_dieabbrev (Dwarf_Die *die, const unsigned char **readp)
       /* Get the abbreviation code.  */
       unsigned int code;
       const unsigned char *addr = die->addr;
-      if (die->cu == NULL)
+      if (die->cu == NULL || addr >= (const unsigned char *) die->cu->endp)
 	return DWARF_END_ABBREV;
       get_uleb128 (code, addr, die->cu->endp);
       if (readp != NULL)
-- 
1.8.3.1

Re: [PATCH] libdw: Check DIE address fall inside the CU before reading abbrev code.

[Mark Wielaard]

On Thu, 2018-06-07 at 20:50 +0200, Mark Wielaard wrote:
> The afl fuzzer found a case where we tried reading an uleb for the DIE
> abbrev code without properly checking the DIE address is inside the CU.

Pushed to master.