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Groups > linux.kernel > #1675680
| From | Edward Cree <ecree@solarflare.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 net-next 12/12] selftests/bpf: variable offset negative tests |
| Date | 2017-06-27 15:10 +0200 |
| Message-ID | <tWYpH-WT-7@gated-at.bofh.it> (permalink) |
| References | <tWYg2-C4-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Variable ctx accesses and stack accesses aren't allowed, because we can't
determine what type of value will be read.
Signed-off-by: Edward Cree <ecree@solarflare.com>
---
tools/testing/selftests/bpf/test_verifier.c | 41 +++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 7df3c34..471fbee 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -5311,6 +5311,47 @@ static struct bpf_test tests[] = {
.errstr = "R0 min value is negative, either use unsigned index or do a if (index >=0) check.",
.result = REJECT,
},
+ {
+ "variable-offset ctx access",
+ .insns = {
+ /* Get an unknown value */
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
+ /* Make it small and 4-byte aligned */
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
+ /* add it to skb. We now have either &skb->len or
+ * &skb->pkt_type, but we don't know which
+ */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2),
+ /* dereference it */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "variable ctx access var_off=(0x0; 0x4)",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_LWT_IN,
+ },
+ {
+ "variable-offset stack access",
+ .insns = {
+ /* Fill the top 8 bytes of the stack */
+ BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+ /* Get an unknown value */
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
+ /* Make it small and 4-byte aligned */
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
+ BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
+ /* add it to fp. We now have either fp-4 or fp-8, but
+ * we don't know which
+ */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
+ /* dereference it */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "variable stack access var_off=(0xfffffffffffffff8; 0x4)",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_LWT_IN,
+ },
};
static int probe_filter_length(const struct bpf_insn *fp)
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[PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Edward Cree <ecree@solarflare.com> - 2017-06-27 15:00 +0200
[PATCH v3 net-next 06/12] selftests/bpf: change test_verifier expectations Edward Cree <ecree@solarflare.com> - 2017-06-27 15:00 +0200
[PATCH v3 net-next 03/12] nfp: change bpf verifier hooks to match new verifier data structures Edward Cree <ecree@solarflare.com> - 2017-06-27 15:00 +0200
Re: [PATCH v3 net-next 03/12] nfp: change bpf verifier hooks to match new verifier data structures Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 22:50 +0200
Re: [PATCH v3 net-next 03/12] nfp: change bpf verifier hooks to match new verifier data structures Jakub Kicinski <jakub.kicinski@netronome.com> - 2017-06-29 05:50 +0200
[PATCH v3 net-next 01/12] selftests/bpf: add test for mixed signed and unsigned bounds checks Edward Cree <ecree@solarflare.com> - 2017-06-27 15:00 +0200
Re: [PATCH v3 net-next 01/12] selftests/bpf: add test for mixed signed and unsigned bounds checks Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 16:00 +0200
[PATCH v3 net-next 07/12] selftests/bpf: rewrite test_align Edward Cree <ecree@solarflare.com> - 2017-06-27 15:00 +0200
[PATCH v3 net-next 09/12] selftests/bpf: add test for bogus operations on pointers Edward Cree <ecree@solarflare.com> - 2017-06-27 15:10 +0200
[PATCH v3 net-next 12/12] selftests/bpf: variable offset negative tests Edward Cree <ecree@solarflare.com> - 2017-06-27 15:10 +0200
[PATCH v3 net-next 08/12] selftests/bpf: add a test to test_align Edward Cree <ecree@solarflare.com> - 2017-06-27 15:10 +0200
[PATCH v3 net-next 10/12] selftests/bpf: don't try to access past MAX_PACKET_OFF in test_verifier Edward Cree <ecree@solarflare.com> - 2017-06-27 15:10 +0200
[PATCH v3 net-next 11/12] selftests/bpf: add tests for subtraction & negative numbers Edward Cree <ecree@solarflare.com> - 2017-06-27 15:10 +0200
Re: [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 16:00 +0200
Re: [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Edward Cree <ecree@solarflare.com> - 2017-06-28 16:20 +0200
Re: [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 22:50 +0200
Re: [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2017-06-28 23:40 +0200
Re: [PATCH v3 net-next 00/12] bpf: rewrite value tracking in verifier Edward Cree <ecree@solarflare.com> - 2017-06-30 18:50 +0200
[TEST PATCH] bpf/verifier: roll back ptr&const handling, and fix signed bounds Edward Cree <ecree@solarflare.com> - 2017-06-30 19:40 +0200
Re: [PATCH v3 net-next 02/12] bpf/verifier: rework value tracking Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 17:20 +0200
Re: [PATCH v3 net-next 02/12] bpf/verifier: rework value tracking Edward Cree <ecree@solarflare.com> - 2017-06-28 18:10 +0200
Re: [PATCH v3 net-next 02/12] bpf/verifier: rework value tracking Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 21:50 +0200
Re: [PATCH v3 net-next 02/12] bpf/verifier: rework value tracking Daniel Borkmann <daniel@iogearbox.net> - 2017-06-28 20:00 +0200
Re: [PATCH v3 net-next 02/12] bpf/verifier: rework value tracking Edward Cree <ecree@solarflare.com> - 2017-06-28 20:30 +0200
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