libelf: Change signed overflow check to unsigned in elf_getdata_rawchunk.

Arithmetic of signed values that overflow causes undefined behaviour
Change to explicit unsigned arithmetic overflow check.

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

diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index 8a11563..68fb0fc 100644 (file)
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,5 +1,10 @@
 2014-11-23  Mark Wielaard  <mjw@redhat.com>
 
+       * elf_getdata_rawchunk.c (elf_getdata_rawchunk): Change signed
+       overflow check to unsigned.
+
+2014-11-23  Mark Wielaard  <mjw@redhat.com>
+
        * note_xlate.h (elf_cvt_note): Copy over any leftover data if
        src != dest. The data is probably part of truncated name/desc.
 

diff --git a/libelf/elf_getdata_rawchunk.c b/libelf/elf_getdata_rawchunk.c
index f4fbe66..63a9914 100644 (file)
--- a/libelf/elf_getdata_rawchunk.c
+++ b/libelf/elf_getdata_rawchunk.c
@@ -1,5 +1,5 @@
 /* Return converted data from raw chunk of ELF file.
-   Copyright (C) 2007 Red Hat, Inc.
+   Copyright (C) 2007, 2014 Red Hat, Inc.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -57,8 +57,9 @@ elf_getdata_rawchunk (elf, offset, size, type)
       return NULL;
     }
 
-  if (unlikely (offset < 0 || offset + (off64_t) size < offset
-               || offset + size > elf->maximum_size))
+  if (unlikely (offset < 0 || (uint64_t) offset > elf->maximum_size
+               || elf->maximum_size - (uint64_t) offset < size))
+
     {
       /* Invalid request.  */
       __libelf_seterrno (ELF_E_INVALID_OP);