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31fd85816d
linux/tools/testing/selftests/bpf
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Yonghong Song 31fd85816d bpf: permits narrower load from bpf program context fields 
Currently, verifier will reject a program if it contains an
narrower load from the bpf context structure. For example,
        __u8 h = __sk_buff->hash, or
        __u16 p = __sk_buff->protocol
        __u32 sample_period = bpf_perf_event_data->sample_period
which are narrower loads of 4-byte or 8-byte field.

This patch solves the issue by:
  . Introduce a new parameter ctx_field_size to carry the
    field size of narrower load from prog type
    specific *__is_valid_access validator back to verifier.
  . The non-zero ctx_field_size for a memory access indicates
    (1). underlying prog type specific convert_ctx_accesses
         supporting non-whole-field access
    (2). the current insn is a narrower or whole field access.
  . In verifier, for such loads where load memory size is
    less than ctx_field_size, verifier transforms it
    to a full field load followed by proper masking.
  . Currently, __sk_buff and bpf_perf_event_data->sample_period
    are supporting narrowing loads.
  . Narrower stores are still not allowed as typical ctx stores
    are just normal stores.

Because of this change, some tests in verifier will fail and
these tests are removed. As a bonus, rename some out of bound
__sk_buff->cb access to proper field name and remove two
redundant "skb cb oob" tests.

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-14 14:56:25 -04:00
..
gnu selftests/bpf: get rid of -D__x86_64__ 2017-05-03 09:51:25 -04:00
include/uapi/linux selftests/bpf: fix broken build due to types.h 2017-05-17 18:45:14 -04:00
.gitignore bpf: Add test_tag to .gitignore 2017-02-10 15:56:08 -05:00
bpf_endian.h bpf: Move endianness BPF helpers out of bpf_util.h 2017-05-01 12:43:49 -07:00
bpf_util.h bpf: Move endianness BPF helpers out of bpf_util.h 2017-05-01 12:43:49 -07:00
config
Makefile bpf: Test for bpf ID 2017-06-06 15:41:24 -04:00
test_align.c selftests/bpf: make correct use of exit codes in bpf selftests 2017-06-13 13:58:56 -04:00
test_iptunnel_common.h selftests/bpf: add a test for basic XDP functionality 2017-04-01 12:45:57 -07:00
test_kmod.sh selftests: do not require bash to run bpf tests 2017-01-05 13:19:47 -07:00
test_l4lb.c bpf: Move endianness BPF helpers out of bpf_util.h 2017-05-01 12:43:49 -07:00
test_lpm_map.c bpf: Remove bpf_sys.h from selftests 2017-02-10 15:56:08 -05:00
test_lru_map.c bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4 2017-04-17 13:55:52 -04:00
test_maps.c bpf, tests: add a test for htab lookup + update traversal 2017-06-10 19:05:46 -04:00
test_obj_id.c bpf: Fix test_obj_id.c for llvm 5.0 2017-06-09 15:15:11 -04:00
test_pkt_access.c selftests/bpf: fix broken build due to types.h 2017-05-17 18:45:14 -04:00
test_progs.c selftests/bpf: make correct use of exit codes in bpf selftests 2017-06-13 13:58:56 -04:00
test_tag.c bpf: Remove bpf_sys.h from selftests 2017-02-10 15:56:08 -05:00
test_tcp_estats.c selftests/bpf: add a test case to check verifier pointer arithmetic 2017-05-03 09:51:25 -04:00
test_verifier.c bpf: permits narrower load from bpf program context fields 2017-06-14 14:56:25 -04:00
test_xdp.c selftests: bpf: Use bpf_endian.h in test_xdp.c 2017-05-02 07:52:01 -07:00