On Fri, Jan 22, 2016 at 9:30 AM, Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
> On Fri, Jan 22, 2016 at 03:30:00PM +0900, Daniel Sangorrin wrote:
>> This patch allows applications to restrict the order in which
>> its system calls may be requested. In order to do that, we
>> provide seccomp-BPF scripts with information about the
>> previous system call requested.
>>
>> An example use case consists of detecting (and stopping) return
>> oriented attacks that disturb the normal execution flow of
>> a user program.
>>
>> Signed-off-by: Daniel Sangorrin <daniel.sangorrin@xxxxxxxxxxxxx>
> ...
>> diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h
> ...
>> struct seccomp_data {
>> int nr;
>> + int prev_nr;
>> __u32 arch;
>> __u64 instruction_pointer;
>> __u64 args[6];
>
> this will break abi for existing seccomp programs.
> New field has to be at the end.
Yeah, and if we break abi, we need to add further sanity checking to
the parser to determine which "version" of seccomp_data we need. I'm
not convinced that there is enough utility here to break ABI.
(Though if we do, I'd like to add tid to the seccomp_data, which has
been requested in the past to make some pid-based arg checks easier to
do.)
-Kees
--
Kees Cook
Chrome OS & Brillo Security
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