Message ID | 1436945834-26660-11-git-send-email-mpe@ellerman.id.au (mailing list archive) |
---|---|
State | RFC |
Headers | show |
On Wed, Jul 15, 2015 at 12:37 AM, Michael Ellerman <mpe@ellerman.id.au> wrote: > The seccomp_bpf test uses BPF_LD|BPF_W|BPF_ABS to load 32-bit values > from seccomp_data->args. On big endian machines this will load the high > word of the argument, which is not what the test wants. > > Borrow a hack from samples/seccomp/bpf-helper.h which changes the offset > on big endian to account for this. > > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > --- > tools/testing/selftests/seccomp/seccomp_bpf.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c > index b2374c131340..51adb9afb511 100644 > --- a/tools/testing/selftests/seccomp/seccomp_bpf.c > +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c > @@ -82,7 +82,13 @@ struct seccomp_data { > }; > #endif > > +#if __BYTE_ORDER == __LITTLE_ENDIAN > #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n])) > +#elif __BYTE_ORDER == __BIG_ENDIAN > +#define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]) + sizeof(__u32)) > +#else > +#error "wut?" > +#endif Ah-ha! Yes, thanks. Could you change the #error to something that describes the particular (impossible) failure condition? "wut? Unknown __BYTE_ORDER?!". Not a huge deal, but I always like verbose errors. :) Especially for "impossible" situations. :) -Kees > > #define SIBLING_EXIT_UNKILLED 0xbadbeef > #define SIBLING_EXIT_FAILURE 0xbadface > -- > 2.1.0 >
On Wed, 2015-07-15 at 08:16 -0700, Kees Cook wrote: > On Wed, Jul 15, 2015 at 12:37 AM, Michael Ellerman <mpe@ellerman.id.au> wrote: > > diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c > > index b2374c131340..51adb9afb511 100644 > > --- a/tools/testing/selftests/seccomp/seccomp_bpf.c > > +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c > > @@ -82,7 +82,13 @@ struct seccomp_data { > > }; > > #endif > > > > +#if __BYTE_ORDER == __LITTLE_ENDIAN > > #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n])) > > +#elif __BYTE_ORDER == __BIG_ENDIAN > > +#define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]) + sizeof(__u32)) > > +#else > > +#error "wut?" > > +#endif > > Ah-ha! Yes, thanks. Could you change the #error to something that > describes the particular (impossible) failure condition? "wut? Unknown > __BYTE_ORDER?!". Not a huge deal, but I always like verbose errors. :) > Especially for "impossible" situations. :) Yeah sorry that was a "quick hack" which got promoted into an actual patch. Fixed to use your message. cheers
diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index b2374c131340..51adb9afb511 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -82,7 +82,13 @@ struct seccomp_data { }; #endif +#if __BYTE_ORDER == __LITTLE_ENDIAN #define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n])) +#elif __BYTE_ORDER == __BIG_ENDIAN +#define syscall_arg(_n) (offsetof(struct seccomp_data, args[_n]) + sizeof(__u32)) +#else +#error "wut?" +#endif #define SIBLING_EXIT_UNKILLED 0xbadbeef #define SIBLING_EXIT_FAILURE 0xbadface
The seccomp_bpf test uses BPF_LD|BPF_W|BPF_ABS to load 32-bit values from seccomp_data->args. On big endian machines this will load the high word of the argument, which is not what the test wants. Borrow a hack from samples/seccomp/bpf-helper.h which changes the offset on big endian to account for this. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- tools/testing/selftests/seccomp/seccomp_bpf.c | 6 ++++++ 1 file changed, 6 insertions(+)