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| author | Alexei Starovoitov <ast@kernel.org> | 2020-09-18 04:09:18 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-09-18 04:56:07 +0200 |
| commit | 09b28d76eac48e922dc293da1aa2b2b85c32aeee (patch) | |
| tree | 2be3e375d9a88923b63ac9c3fda927d25073483a /tools | |
| parent | bpf: allow for tailcalls in BPF subprograms for x64 JIT (diff) | |
| download | linux-09b28d76eac48e922dc293da1aa2b2b85c32aeee.tar.xz linux-09b28d76eac48e922dc293da1aa2b2b85c32aeee.zip | |
bpf: Add abnormal return checks.
LD_[ABS|IND] instructions may return from the function early. bpf_tail_call
pseudo instruction is either fallthrough or return. Allow them in the
subprograms only when subprograms are BTF annotated and have scalar return
types. Allow ld_abs and tail_call in the main program even if it calls into
subprograms. In the past that was not ok to do for ld_abs, since it was JITed
with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs
looks like normal exit insn from JIT point of view, so it's safe to allow them
in the main program.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/verifier/calls.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c index 94258c6b5235..c4f5d909e58a 100644 --- a/tools/testing/selftests/bpf/verifier/calls.c +++ b/tools/testing/selftests/bpf/verifier/calls.c @@ -647,13 +647,14 @@ .result = REJECT, }, { - "calls: ld_abs with changing ctx data in callee", + "calls: subprog call with ld_abs in main prog", .insns = { BPF_MOV64_REG(BPF_REG_6, BPF_REG_1), BPF_LD_ABS(BPF_B, 0), BPF_LD_ABS(BPF_H, 0), BPF_LD_ABS(BPF_W, 0), BPF_MOV64_REG(BPF_REG_7, BPF_REG_6), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 5), BPF_MOV64_REG(BPF_REG_6, BPF_REG_7), BPF_LD_ABS(BPF_B, 0), @@ -666,8 +667,7 @@ BPF_EXIT_INSN(), }, .prog_type = BPF_PROG_TYPE_SCHED_CLS, - .errstr = "BPF_LD_[ABS|IND] instructions cannot be mixed", - .result = REJECT, + .result = ACCEPT, }, { "calls: two calls with bad fallthrough", |