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authorJakub Kicinski <jakub.kicinski@netronome.com>2019-03-21 14:34:36 -0700
committerAlexei Starovoitov <ast@kernel.org>2019-03-21 19:57:02 -0700
commit83d163124cf1104cca5b668d5fe6325715a60855 (patch)
tree0efb88a71d45a495137c28f26eb94575bf28ff2c /tools/testing/selftests/bpf/verifier
parentbpf: do not restore dst_reg when cur_state is freed (diff)
downloadlinux-dev-83d163124cf1104cca5b668d5fe6325715a60855.tar.xz
linux-dev-83d163124cf1104cca5b668d5fe6325715a60855.zip
bpf: verifier: propagate liveness on all frames
Commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences") connected up parentage chains of all frames of the stack. It didn't, however, ensure propagate_liveness() propagates all liveness information along those chains. This means pruning happening in the callee may generate explored states with incomplete liveness for the chains in lower frames of the stack. The included selftest is similar to the prior one from commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences"), where callee would prune regardless of the difference in r8 state. Now we also initialize r9 to 0 or 1 based on a result from get_random(). r9 is never read so the walk with r9 = 0 gets pruned (correctly) after the walk with r9 = 1 completes. The selftest is so arranged that the pruning will happen in the callee. Since callee does not propagate read marks of r8, the explored state at the pruning point prior to the callee will now ignore r8. Propagate liveness on all frames of the stack when pruning. Fixes: f4d7e40a5b71 ("bpf: introduce function calls (verification)") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/testing/selftests/bpf/verifier')
-rw-r--r--tools/testing/selftests/bpf/verifier/calls.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c
index 4004891afa9c..f2ccae39ee66 100644
--- a/tools/testing/selftests/bpf/verifier/calls.c
+++ b/tools/testing/selftests/bpf/verifier/calls.c
@@ -1940,3 +1940,28 @@
.errstr = "!read_ok",
.result = REJECT,
},
+{
+ "calls: cross frame pruning - liveness propagation",
+ .insns = {
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+ BPF_MOV64_IMM(BPF_REG_8, 0),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_MOV64_IMM(BPF_REG_8, 1),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+ BPF_MOV64_IMM(BPF_REG_9, 0),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_MOV64_IMM(BPF_REG_9, 1),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_8, 1, 1),
+ BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+ .errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+ .errstr = "!read_ok",
+ .result = REJECT,
+},