kernel.git/tools/testing/selftests/bpf/test_verifier.c, branch linux-5.10.y

selftests/bpf: Add verifier test for PTR_TO_MEM spill

2023-07-27T06:44:15Z

commit 4237e9f4a96228ccc8a7abe5e4b30834323cd353 upstream. Add a test to check that the verifier is able to recognize spilling of PTR_TO_MEM registers, by reserving a ringbuf buffer, forcing the spill of a pointer holding the buffer address to the stack, filling it back in from the stack and writing to the memory area pointed by it. The patch was partially contributed by CyberArk Software, Inc. Signed-off-by: Gilad Reti Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Acked-by: KP Singh Link: https://lore.kernel.org/bpf/20210113053810.13518-2-gilad.reti@gmail.com Cc: Lorenz Bauer Signed-off-by: Greg Kroah-Hartman

selftests: bpf: Don't run sk_lookup in verifier tests

2022-08-03T10:00:52Z

commit b4f894633fa14d7d46ba7676f950b90a401504bb upstream. sk_lookup doesn't allow setting data_in for bpf_prog_run. This doesn't play well with the verifier tests, since they always set a 64 byte input buffer. Allow not running verifier tests by setting bpf_test.runs to a negative value and don't run the ctx access case for sk_lookup. We have dedicated ctx access tests so skipping here doesn't reduce coverage. Signed-off-by: Lorenz Bauer Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210303101816.36774-6-lmb@cloudflare.com Signed-off-by: Tianchen Ding Signed-off-by: Greg Kroah-Hartman

bpf, selftests: Adjust few selftest outcomes wrt unreachable code

2021-08-08T07:05:24Z

commit 973377ffe8148180b2651825b92ae91988141b05 upstream In almost all cases from test_verifier that have been changed in here, we've had an unreachable path with a load from a register which has an invalid address on purpose. This was basically to make sure that we never walk this path and to have the verifier complain if it would otherwise. Change it to match on the right error for unprivileged given we now test these paths under speculative execution. There's one case where we match on exact # of insns_processed. Due to the extra path, this will of course mismatch on unprivileged. Thus, restrict the test->insn_processed check to privileged-only. In one other case, we result in a 'pointer comparison prohibited' error. This is similarly due to verifying an 'invalid' branch where we end up with a value pointer on one side of the comparison. Signed-off-by: Daniel Borkmann Reviewed-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

selftests/bpf: Add verifier test for d_path helper

2020-08-25T22:41:15Z

Adding verifier test for attaching tracing program and calling d_path helper from within and testing that it's allowed for dentry_open function and denied for 'd_path' function with appropriate error. Signed-off-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200825192124.710397-13-jolsa@kernel.org

selftests/bpf: Use CAP_BPF and CAP_PERFMON in tests

2020-05-15T15:29:41Z

Make all test_verifier test exercise CAP_BPF and CAP_PERFMON Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200513230355.7858-4-alexei.starovoitov@gmail.com

selftests/bpf: Test allowed maps for bpf_sk_select_reuseport

2020-04-30T14:21:14Z

Check that verifier allows passing a map of type: BPF_MAP_TYPE_REUSEPORT_SOCKARRARY, or BPF_MAP_TYPE_SOCKMAP, or BPF_MAP_TYPE_SOCKHASH ... to bpf_sk_select_reuseport helper. Suggested-by: John Fastabend Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200430104738.494180-1-jakub@cloudflare.com

bpf: Make verifier log more relevant by default

2020-04-26T16:47:37Z

To make BPF verifier verbose log more releavant and easier to use to debug verification failures, "pop" parts of log that were successfully verified. This has effect of leaving only verifier logs that correspond to code branches that lead to verification failure, which in practice should result in much shorter and more relevant verifier log dumps. This behavior is made the default behavior and can be overriden to do exhaustive logging by specifying BPF_LOG_LEVEL2 log level. Using BPF_LOG_LEVEL2 to disable this behavior is not ideal, because in some cases it's good to have BPF_LOG_LEVEL2 per-instruction register dump verbosity, but still have only relevant verifier branches logged. But for this patch, I didn't want to add any new flags. It might be worth-while to just rethink how BPF verifier logging is performed and requested and streamline it a bit. But this trimming of successfully verified branches seems to be useful and a good default behavior. To test this, I modified runqslower slightly to introduce read of uninitialized stack variable. Log (**truncated in the middle** to save many lines out of this commit message) BEFORE this change: ; int handle__sched_switch(u64 *ctx) 0: (bf) r6 = r1 ; struct task_struct *prev = (struct task_struct *)ctx[1]; 1: (79) r1 = *(u64 *)(r6 +8) func 'sched_switch' arg1 has btf_id 151 type STRUCT 'task_struct' 2: (b7) r2 = 0 ; struct event event = {}; 3: (7b) *(u64 *)(r10 -24) = r2 last_idx 3 first_idx 0 regs=4 stack=0 before 2: (b7) r2 = 0 4: (7b) *(u64 *)(r10 -32) = r2 5: (7b) *(u64 *)(r10 -40) = r2 6: (7b) *(u64 *)(r10 -48) = r2 ; if (prev->state == TASK_RUNNING) [ ... instruction dump from insn #7 through #50 are cut out ... ] 51: (b7) r2 = 16 52: (85) call bpf_get_current_comm#16 last_idx 52 first_idx 42 regs=4 stack=0 before 51: (b7) r2 = 16 ; bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, 53: (bf) r1 = r6 54: (18) r2 = 0xffff8881f3868800 56: (18) r3 = 0xffffffff 58: (bf) r4 = r7 59: (b7) r5 = 32 60: (85) call bpf_perf_event_output#25 last_idx 60 first_idx 53 regs=20 stack=0 before 59: (b7) r5 = 32 61: (bf) r2 = r10 ; event.pid = pid; 62: (07) r2 += -16 ; bpf_map_delete_elem(&start, &pid); 63: (18) r1 = 0xffff8881f3868000 65: (85) call bpf_map_delete_elem#3 ; } 66: (b7) r0 = 0 67: (95) exit from 44 to 66: safe from 34 to 66: safe from 11 to 28: R1_w=inv0 R2_w=inv0 R6_w=ctx(id=0,off=0,imm=0) R10=fp0 fp-8=mmmm???? fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000 ; bpf_map_update_elem(&start, &pid, &ts, 0); 28: (bf) r2 = r10 ; 29: (07) r2 += -16 ; tsp = bpf_map_lookup_elem(&start, &pid); 30: (18) r1 = 0xffff8881f3868000 32: (85) call bpf_map_lookup_elem#1 invalid indirect read from stack off -16+0 size 4 processed 65 insns (limit 1000000) max_states_per_insn 1 total_states 5 peak_states 5 mark_read 4 Notice how there is a successful code path from instruction 0 through 67, few successfully verified jumps (44->66, 34->66), and only after that 11->28 jump plus error on instruction #32. AFTER this change (full verifier log, **no truncation**): ; int handle__sched_switch(u64 *ctx) 0: (bf) r6 = r1 ; struct task_struct *prev = (struct task_struct *)ctx[1]; 1: (79) r1 = *(u64 *)(r6 +8) func 'sched_switch' arg1 has btf_id 151 type STRUCT 'task_struct' 2: (b7) r2 = 0 ; struct event event = {}; 3: (7b) *(u64 *)(r10 -24) = r2 last_idx 3 first_idx 0 regs=4 stack=0 before 2: (b7) r2 = 0 4: (7b) *(u64 *)(r10 -32) = r2 5: (7b) *(u64 *)(r10 -40) = r2 6: (7b) *(u64 *)(r10 -48) = r2 ; if (prev->state == TASK_RUNNING) 7: (79) r2 = *(u64 *)(r1 +16) ; if (prev->state == TASK_RUNNING) 8: (55) if r2 != 0x0 goto pc+19 R1_w=ptr_task_struct(id=0,off=0,imm=0) R2_w=inv0 R6_w=ctx(id=0,off=0,imm=0) R10=fp0 fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000 ; trace_enqueue(prev->tgid, prev->pid); 9: (61) r1 = *(u32 *)(r1 +1184) 10: (63) *(u32 *)(r10 -4) = r1 ; if (!pid || (targ_pid && targ_pid != pid)) 11: (15) if r1 == 0x0 goto pc+16 from 11 to 28: R1_w=inv0 R2_w=inv0 R6_w=ctx(id=0,off=0,imm=0) R10=fp0 fp-8=mmmm???? fp-24_w=00000000 fp-32_w=00000000 fp-40_w=00000000 fp-48_w=00000000 ; bpf_map_update_elem(&start, &pid, &ts, 0); 28: (bf) r2 = r10 ; 29: (07) r2 += -16 ; tsp = bpf_map_lookup_elem(&start, &pid); 30: (18) r1 = 0xffff8881db3ce800 32: (85) call bpf_map_lookup_elem#1 invalid indirect read from stack off -16+0 size 4 processed 65 insns (limit 1000000) max_states_per_insn 1 total_states 5 peak_states 5 mark_read 4 Notice how in this case, there are 0-11 instructions + jump from 11 to 28 is recorded + 28-32 instructions with error on insn #32. test_verifier test runner was updated to specify BPF_LOG_LEVEL2 for VERBOSE_ACCEPT expected result due to potentially "incomplete" success verbose log at BPF_LOG_LEVEL1. On success, verbose log will only have a summary of number of processed instructions, etc, but no branch tracing log. Having just a last succesful branch tracing seemed weird and confusing. Having small and clean summary log in success case seems quite logical and nice, though. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200423195850.1259827-1-andriin@fb.com

bpf: Add further test_verifier cases for record_func_key

2019-12-19T21:39:22Z

Expand dummy prog generation such that we can easily check on return codes and add few more test cases to make sure we keep on tracking pruning behavior. # ./test_verifier [...] #1066/p XDP pkt read, pkt_data <= pkt_meta', bad access 1 OK #1067/p XDP pkt read, pkt_data <= pkt_meta', bad access 2 OK Summary: 1580 PASSED, 0 SKIPPED, 0 FAILED Also verified that JIT dump of added test cases looks good. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/df7200b6021444fd369376d227de917357285b65.1576789878.git.daniel@iogearbox.net

selftests/bpf: verifier precise tests

2019-08-27T22:30:11Z

Use BPF_F_TEST_STATE_FREQ flag to check that precision tracking works as expected by comparing every step it takes. Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Signed-off-by: Daniel Borkmann

selftests/bpf: Add selftests for bpf_perf_event_output

2019-07-26T00:56:00Z

Software event output is only enabled by a few prog types. This test is to ensure that all supported types are enabled for bpf_perf_event_output successfully. Signed-off-by: Allan Zhang Acked-by: Song Liu Signed-off-by: Alexei Starovoitov