From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
Hector Marco-Gisbert <hecmargi@upv.es>,
Ismael Ripoll Ripoll <iripoll@upv.es>,
Alexander Viro <viro@zeniv.linux.org.uk>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Oleg Nesterov <oleg@redhat.com>,
Chen Gang <gang.chen.5i5j@gmail.com>,
Michal Hocko <mhocko@suse.com>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 0/2] binfmt_elf: fix calculations for bss padding
Date: Fri, 8 Jul 2016 14:48:12 -0700 [thread overview]
Message-ID: <1468014494-25291-1-git-send-email-keescook@chromium.org> (raw)
This fixes a double-bug in ELF loading, as noticed by Hector
Marco-Gisbert. To quote his original email:
The size of the bss section for some interpreters is not correctly
calculated resulting in unnecessary calls to vm_brk() with enormous size
values.
The bug appears when loading some interpreters with a small bss size. Once
the last loadable segment has been loaded, the bss section is zeroed up to
the page boundary and the elf_bss variable is updated to this new page
boundary. Because of this update (alignment), the last_bss could be less
than elf_bss and the subtraction "last_bss - elf_bss" value could overflow.
...
[e.g.] The size value requested to the vm_brk() call (last_bss - elf_bss) is
0xfffffffffffff938 and internally this size is page aligned in the do_brk()
function resulting in a 0 length request.
This series takes a slightly different approach to fixing it and updates
vm_brk to refuse bad allocation sizes.
-Kees
next reply other threads:[~2016-07-08 21:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-08 21:48 Kees Cook [this message]
2016-07-08 21:48 ` [PATCH 1/2] binfmt_elf: fix calculations for bss padding Kees Cook
2016-07-12 22:32 ` Kees Cook
2016-07-08 21:48 ` [PATCH 2/2] mm: refuse wrapped vm_brk requests Kees Cook
2016-07-11 12:28 ` Oleg Nesterov
2016-07-11 18:01 ` Kees Cook
2016-07-12 13:39 ` Oleg Nesterov
2016-07-12 17:15 ` Kees Cook
2016-07-13 17:00 ` Oleg Nesterov
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