* [PATCH net] bpf: change bpf_probe_write_user to bpf_trace_printk in test_verifier
@ 2017-11-21 19:23 Yonghong Song
2017-11-21 20:35 ` Daniel Borkmann
0 siblings, 1 reply; 2+ messages in thread
From: Yonghong Song @ 2017-11-21 19:23 UTC (permalink / raw)
To: ast, daniel, netdev; +Cc: kernel-team
There are four tests in test_verifier using bpf_probe_write_user
helper. These four tests will emit the following kernel messages
[ 12.974753] test_verifier[220] is installing a program with bpf_probe_write_user
helper that may corrupt user memory!
[ 12.979285] test_verifier[220] is installing a program with bpf_probe_write_user
helper that may corrupt user memory!
......
This may confuse certain users. This patch replaces bpf_probe_write_user
with bpf_trace_printk. The test_verifier already uses bpf_trace_printk
earlier in the test and a trace_printk warning message has been printed.
So this patch does not emit any more kernel messages.
Signed-off-by: Yonghong Song <yhs@fb.com>
---
tools/testing/selftests/bpf/test_verifier.c | 39 ++++++++++++-----------------
1 file changed, 16 insertions(+), 23 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index bf092b8..2a5267b 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -4377,11 +4377,10 @@ static struct bpf_test tests[] = {
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
- BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
- BPF_MOV64_IMM(BPF_REG_1, 0),
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
- BPF_MOV64_IMM(BPF_REG_3, 0),
- BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_EMIT_CALL(BPF_FUNC_trace_printk),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
@@ -4481,14 +4480,12 @@ static struct bpf_test tests[] = {
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
- BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1,
offsetof(struct test_val, foo)),
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
- BPF_MOV64_IMM(BPF_REG_1, 0),
- BPF_MOV64_IMM(BPF_REG_3, 0),
- BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_EMIT_CALL(BPF_FUNC_trace_printk),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
@@ -4618,18 +4615,16 @@ static struct bpf_test tests[] = {
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
- BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_MOV64_IMM(BPF_REG_3, 0),
BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
- BPF_MOV64_IMM(BPF_REG_1, 0),
- BPF_MOV64_IMM(BPF_REG_3, 0),
- BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_EMIT_CALL(BPF_FUNC_trace_printk),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
- .errstr = "R2 min value is outside of the array range",
+ .errstr = "R1 min value is outside of the array range",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
@@ -4760,20 +4755,18 @@ static struct bpf_test tests[] = {
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
BPF_LD_MAP_FD(BPF_REG_1, 0),
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
- BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_0, 0),
BPF_JMP_IMM(BPF_JGT, BPF_REG_3,
- offsetof(struct test_val, foo), 4),
+ offsetof(struct test_val, foo), 3),
BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_3),
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
- BPF_MOV64_IMM(BPF_REG_1, 0),
- BPF_MOV64_IMM(BPF_REG_3, 0),
- BPF_EMIT_CALL(BPF_FUNC_probe_write_user),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_EMIT_CALL(BPF_FUNC_trace_printk),
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
- .errstr = "R2 min value is outside of the array range",
+ .errstr = "R1 min value is outside of the array range",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
},
--
2.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] bpf: change bpf_probe_write_user to bpf_trace_printk in test_verifier
2017-11-21 19:23 [PATCH net] bpf: change bpf_probe_write_user to bpf_trace_printk in test_verifier Yonghong Song
@ 2017-11-21 20:35 ` Daniel Borkmann
0 siblings, 0 replies; 2+ messages in thread
From: Daniel Borkmann @ 2017-11-21 20:35 UTC (permalink / raw)
To: Yonghong Song, ast, netdev; +Cc: kernel-team
On 11/21/2017 08:23 PM, Yonghong Song wrote:
> There are four tests in test_verifier using bpf_probe_write_user
> helper. These four tests will emit the following kernel messages
> [ 12.974753] test_verifier[220] is installing a program with bpf_probe_write_user
> helper that may corrupt user memory!
> [ 12.979285] test_verifier[220] is installing a program with bpf_probe_write_user
> helper that may corrupt user memory!
> ......
>
> This may confuse certain users. This patch replaces bpf_probe_write_user
> with bpf_trace_printk. The test_verifier already uses bpf_trace_printk
> earlier in the test and a trace_printk warning message has been printed.
> So this patch does not emit any more kernel messages.
>
> Signed-off-by: Yonghong Song <yhs@fb.com>
Applied to bpf tree, thanks Yonghong!
^ permalink raw reply [flat|nested] 2+ messages in thread
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