Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1675681
| From | Edward Cree <ecree@solarflare.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 net-next 08/12] selftests/bpf: add a test to test_align |
| Date | 2017-06-27 15:10 +0200 |
| Message-ID | <tWYpH-WT-13@gated-at.bofh.it> (permalink) |
| References | <tWYg2-C4-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
New test adds 14 to the unknown value before adding to the packet pointer,
meaning there's no 'fixed offset' field and instead we add into the
var_off, yielding a '4n+2' value.
Signed-off-by: Edward Cree <ecree@solarflare.com>
---
tools/testing/selftests/bpf/test_align.c | 67 ++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c
index 031bba8..5165d8e 100644
--- a/tools/testing/selftests/bpf/test_align.c
+++ b/tools/testing/selftests/bpf/test_align.c
@@ -374,6 +374,73 @@ static struct bpf_align_test tests[] = {
{33, "R5=pkt(id=4,off=18,r=22,umax_value=2040,var_off=(0x0; 0x7fc))"},
},
},
+ {
+ .descr = "packet variable offset 2",
+ .insns = {
+ /* Create an unknown offset, (4n+2)-aligned */
+ LOAD_UNKNOWN(BPF_REG_6),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 14),
+ /* Add it to the packet pointer */
+ BPF_MOV64_REG(BPF_REG_5, BPF_REG_2),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
+ /* Check bounds and perform a read */
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0),
+ /* Make a (4n) offset from the value we just read */
+ BPF_ALU64_IMM(BPF_AND, BPF_REG_6, 0xff),
+ BPF_ALU64_IMM(BPF_LSH, BPF_REG_6, 2),
+ /* Add it to the packet pointer */
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_5, BPF_REG_6),
+ /* Check bounds and perform a read */
+ BPF_MOV64_REG(BPF_REG_4, BPF_REG_5),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 4),
+ BPF_JMP_REG(BPF_JGE, BPF_REG_3, BPF_REG_4, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_5, 0),
+ BPF_MOV64_IMM(BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .matches = {
+ /* Calculated offset in R6 has unknown value, but known
+ * alignment of 4.
+ */
+ {8, "R2=pkt(id=0,off=0,r=8,imm=0)"},
+ {8, "R6=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"},
+ /* Adding 14 makes R6 be (4n+2) */
+ {9, "R6=inv(id=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"},
+ /* Packet pointer has (4n+2) offset */
+ {11, "R5=pkt(id=1,off=0,r=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"},
+ {13, "R4=pkt(id=1,off=4,r=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"},
+ /* At the time the word size load is performed from R5,
+ * its total fixed offset is NET_IP_ALIGN + reg->off (0)
+ * which is 2. Then the variable offset is (4n+2), so
+ * the total offset is 4-byte aligned and meets the
+ * load's requirements.
+ */
+ {15, "R5=pkt(id=1,off=0,r=4,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"},
+ /* Newly read value in R6 was shifted left by 2, so has
+ * known alignment of 4.
+ */
+ {18, "R6=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"},
+ /* Added (4n) to packet pointer's (4n+2) var_off, giving
+ * another (4n+2).
+ */
+ {19, "R5=pkt(id=2,off=0,r=0,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"},
+ {21, "R4=pkt(id=2,off=4,r=0,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"},
+ /* At the time the word size load is performed from R5,
+ * its total fixed offset is NET_IP_ALIGN + reg->off (0)
+ * which is 2. Then the variable offset is (4n+2), so
+ * the total offset is 4-byte aligned and meets the
+ * load's requirements.
+ */
+ {23, "R5=pkt(id=2,off=0,r=4,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc))"},
+ },
+ },
};
static int probe_filter_length(const struct bpf_insn *fp)
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[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
csiph-web