kernel.git/tools/testing/selftests/bpf/test_sysctl.c, branch linux-5.3.y

bpf: Allow narrow loads of bpf_sysctl fields with offset > 0

2019-12-04T21:33:18Z

[ Upstream commit 7541c87c9b7a7e07c84481f37f2c19063b44469b ] "ctx:file_pos sysctl:read read ok narrow" works on s390 by accident: it reads the wrong byte, which happens to have the expected value of 0. Improve the test by seeking to the 4th byte and expecting 4 instead of 0. This makes the latent problem apparent: the test attempts to read the first byte of bpf_sysctl.file_pos, assuming this is the least-significant byte, which is not the case on big-endian machines: a non-zero offset is needed. The point of the test is to verify narrow loads, so we cannot cheat our way out by simply using BPF_W. The existence of the test means that such loads have to be supported, most likely because llvm can generate them. Fix the test by adding a big-endian variant, which uses an offset to access the least-significant byte of bpf_sysctl.file_pos. This reveals the final problem: verifier rejects accesses to bpf_sysctl fields with offset > 0. Such accesses are already allowed for a wide range of structs: __sk_buff, bpf_sock_addr and sk_msg_md to name a few. Extend this support to bpf_sysctl by using bpf_ctx_range instead of offsetof when matching field offsets. Fixes: 7b146cebe30c ("bpf: Sysctl hook") Fixes: e1550bfe0de4 ("bpf: Add file_pos field to bpf_sysctl ctx") Fixes: 9a1027e52535 ("selftests/bpf: Test file_pos field in bpf_sysctl ctx") Signed-off-by: Ilya Leoshkevich Signed-off-by: Alexei Starovoitov Acked-by: Andrey Ignatov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20191028122902.9763-1-iii@linux.ibm.com Signed-off-by: Sasha Levin

selftests/bpf: C based test for sysctl and strtoX

2019-04-12T20:54:59Z

Add C based test for a few bpf_sysctl_* helpers and bpf_strtoul. Make sure that sysctl can be identified by name and that multiple integers can be parsed from sysctl value with bpf_strtoul. net/ipv4/tcp_mem is chosen as a testing sysctl, it contains 3 unsigned longs, they all are parsed and compared (val[0] < val[1] < val[2]). Example of output: # ./test_sysctl ... Test case: C prog: deny all writes .. [PASS] Test case: C prog: deny access by name .. [PASS] Test case: C prog: read tcp_mem .. [PASS] Summary: 39 PASSED, 0 FAILED Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov

selftests/bpf: Test bpf_strtol and bpf_strtoul helpers

2019-04-12T20:54:59Z

Test that bpf_strtol and bpf_strtoul helpers can be used to convert provided buffer to long or unsigned long correspondingly and return both correct result and number of consumed bytes, or proper errno. Example of output: # ./test_sysctl .. Test case: bpf_strtoul one number string .. [PASS] Test case: bpf_strtoul multi number string .. [PASS] Test case: bpf_strtoul buf_len = 0, reject .. [PASS] Test case: bpf_strtoul supported base, ok .. [PASS] Test case: bpf_strtoul unsupported base, EINVAL .. [PASS] Test case: bpf_strtoul buf with spaces only, EINVAL .. [PASS] Test case: bpf_strtoul negative number, EINVAL .. [PASS] Test case: bpf_strtol negative number, ok .. [PASS] Test case: bpf_strtol hex number, ok .. [PASS] Test case: bpf_strtol max long .. [PASS] Test case: bpf_strtol overflow, ERANGE .. [PASS] Summary: 36 PASSED, 0 FAILED Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov

selftests/bpf: Test file_pos field in bpf_sysctl ctx

2019-04-12T20:54:59Z

Test access to file_pos field of bpf_sysctl context, both read (incl. narrow read) and write. # ./test_sysctl ... Test case: ctx:file_pos sysctl:read read ok .. [PASS] Test case: ctx:file_pos sysctl:read read ok narrow .. [PASS] Test case: ctx:file_pos sysctl:read write ok .. [PASS] ... Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov

selftests/bpf: Test bpf_sysctl_{get,set}_new_value helpers

2019-04-12T20:54:59Z

Test that new value provided by user space on sysctl write can be read by bpf_sysctl_get_new_value and overridden by bpf_sysctl_set_new_value. # ./test_sysctl ... Test case: sysctl_get_new_value sysctl:read EINVAL .. [PASS] Test case: sysctl_get_new_value sysctl:write ok .. [PASS] Test case: sysctl_get_new_value sysctl:write ok long .. [PASS] Test case: sysctl_get_new_value sysctl:write E2BIG .. [PASS] Test case: sysctl_set_new_value sysctl:read EINVAL .. [PASS] Test case: sysctl_set_new_value sysctl:write ok .. [PASS] Summary: 22 PASSED, 0 FAILED Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov

selftests/bpf: Test sysctl_get_current_value helper

2019-04-12T20:54:59Z

Test sysctl_get_current_value on sysctl read and write, buffers with enough space and too small buffers to get E2BIG and truncated result, etc. # ./test_sysctl ... Test case: sysctl_get_current_value sysctl:read ok, gt .. [PASS] Test case: sysctl_get_current_value sysctl:read ok, eq .. [PASS] Test case: sysctl_get_current_value sysctl:read E2BIG truncated .. [PASS] Test case: sysctl_get_current_value sysctl:read EINVAL .. [PASS] Test case: sysctl_get_current_value sysctl:write ok .. [PASS] Summary: 16 PASSED, 0 FAILED Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov

selftests/bpf: Test bpf_sysctl_get_name helper

2019-04-12T20:54:58Z

Test w/ and w/o BPF_F_SYSCTL_BASE_NAME, buffers with enough space and too small buffers to get E2BIG and truncated result, etc. # ./test_sysctl ... Test case: sysctl_get_name sysctl_value:base ok .. [PASS] Test case: sysctl_get_name sysctl_value:base E2BIG truncated .. [PASS] Test case: sysctl_get_name sysctl:full ok .. [PASS] Test case: sysctl_get_name sysctl:full E2BIG truncated .. [PASS] Test case: sysctl_get_name sysctl:full E2BIG truncated small .. [PASS] Summary: 11 PASSED, 0 FAILED Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov

selftests/bpf: Test BPF_CGROUP_SYSCTL

2019-04-12T20:54:58Z

Add unit test for BPF_PROG_TYPE_CGROUP_SYSCTL program type. Test that program can allow/deny access. Test both valid and invalid accesses to ctx->write. Example of output: # ./test_sysctl Test case: sysctl wrong attach_type .. [PASS] Test case: sysctl:read allow all .. [PASS] Test case: sysctl:read deny all .. [PASS] Test case: ctx:write sysctl:read read ok .. [PASS] Test case: ctx:write sysctl:write read ok .. [PASS] Test case: ctx:write sysctl:read write reject .. [PASS] Summary: 6 PASSED, 0 FAILED Signed-off-by: Andrey Ignatov Signed-off-by: Alexei Starovoitov