* [PATCH 4.19 1/2] bpf: Fix the off-by-two error in range markings
2022-08-29 11:50 [PATCH 4.19 0/2] bpf: fix test_verifier, test_align selftests Ovidiu Panait
@ 2022-08-29 11:50 ` Ovidiu Panait
2022-08-29 11:50 ` [PATCH 4.19 2/2] selftests/bpf: Fix test_align verifier log patterns Ovidiu Panait
2022-09-01 10:09 ` [PATCH 4.19 0/2] bpf: fix test_verifier, test_align selftests Greg KH
2 siblings, 0 replies; 4+ messages in thread
From: Ovidiu Panait @ 2022-08-29 11:50 UTC (permalink / raw)
To: stable
Cc: raajeshdasari, jean-philippe, Maxim Mikityanskiy,
Daniel Borkmann, Ovidiu Panait
From: Maxim Mikityanskiy <maximmi@nvidia.com>
commit 2fa7d94afc1afbb4d702760c058dc2d7ed30f226 upstream.
The first commit cited below attempts to fix the off-by-one error that
appeared in some comparisons with an open range. Due to this error,
arithmetically equivalent pieces of code could get different verdicts
from the verifier, for example (pseudocode):
// 1. Passes the verifier:
if (data + 8 > data_end)
return early
read *(u64 *)data, i.e. [data; data+7]
// 2. Rejected by the verifier (should still pass):
if (data + 7 >= data_end)
return early
read *(u64 *)data, i.e. [data; data+7]
The attempted fix, however, shifts the range by one in a wrong
direction, so the bug not only remains, but also such piece of code
starts failing in the verifier:
// 3. Rejected by the verifier, but the check is stricter than in #1.
if (data + 8 >= data_end)
return early
read *(u64 *)data, i.e. [data; data+7]
The change performed by that fix converted an off-by-one bug into
off-by-two. The second commit cited below added the BPF selftests
written to ensure than code chunks like #3 are rejected, however,
they should be accepted.
This commit fixes the off-by-two error by adjusting new_range in the
right direction and fixes the tests by changing the range into the
one that should actually fail.
Fixes: fb2a311a31d3 ("bpf: fix off by one for range markings with L{T, E} patterns")
Fixes: b37242c773b2 ("bpf: add test cases to bpf selftests to cover all access tests")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211130181607.593149-1-maximmi@nvidia.com
[OP: cherry-pick selftest changes only]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
---
tools/testing/selftests/bpf/test_verifier.c | 32 ++++++++++-----------
1 file changed, 16 insertions(+), 16 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 858e55143233..9a103bd3542c 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -9108,10 +9108,10 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9166,10 +9166,10 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9279,9 +9279,9 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9451,9 +9451,9 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data_end)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9564,10 +9564,10 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGT, BPF_REG_3, BPF_REG_1, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9622,10 +9622,10 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLT, BPF_REG_1, BPF_REG_3, 1),
BPF_JMP_IMM(BPF_JA, 0, 0, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9735,9 +9735,9 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JGE, BPF_REG_1, BPF_REG_3, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
@@ -9907,9 +9907,9 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct xdp_md, data)),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 8),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 6),
BPF_JMP_REG(BPF_JLE, BPF_REG_3, BPF_REG_1, 1),
- BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8),
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -6),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
--
2.37.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 4.19 2/2] selftests/bpf: Fix test_align verifier log patterns
2022-08-29 11:50 [PATCH 4.19 0/2] bpf: fix test_verifier, test_align selftests Ovidiu Panait
2022-08-29 11:50 ` [PATCH 4.19 1/2] bpf: Fix the off-by-two error in range markings Ovidiu Panait
@ 2022-08-29 11:50 ` Ovidiu Panait
2022-09-01 10:09 ` [PATCH 4.19 0/2] bpf: fix test_verifier, test_align selftests Greg KH
2 siblings, 0 replies; 4+ messages in thread
From: Ovidiu Panait @ 2022-08-29 11:50 UTC (permalink / raw)
To: stable
Cc: raajeshdasari, jean-philippe, Stanislav Fomichev,
Daniel Borkmann, Ovidiu Panait
From: Stanislav Fomichev <sdf@google.com>
commit 5366d2269139ba8eb6a906d73a0819947e3e4e0a upstream.
Commit 294f2fc6da27 ("bpf: Verifer, adjust_scalar_min_max_vals to always
call update_reg_bounds()") changed the way verifier logs some of its state,
adjust the test_align accordingly. Where possible, I tried to not copy-paste
the entire log line and resorted to dropping the last closing brace instead.
Fixes: 294f2fc6da27 ("bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds()")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200515194904.229296-1-sdf@google.com
[OP: adjust for 4.19 selftests, apply only the relevant diffs]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
---
tools/testing/selftests/bpf/test_align.c | 27 ++++++++++++------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/tools/testing/selftests/bpf/test_align.c b/tools/testing/selftests/bpf/test_align.c
index 3c789d03b629..0ae7a7415414 100644
--- a/tools/testing/selftests/bpf/test_align.c
+++ b/tools/testing/selftests/bpf/test_align.c
@@ -359,15 +359,15 @@ static struct bpf_align_test tests[] = {
* is still (4n), fixed offset is not changed.
* Also, we create a new reg->id.
*/
- {29, "R5_w=pkt(id=4,off=18,r=0,umax_value=2040,var_off=(0x0; 0x7fc))"},
+ {29, "R5_w=pkt(id=4,off=18,r=0,umax_value=2040,var_off=(0x0; 0x7fc)"},
/* At the time the word size load is performed from R5,
* its total fixed offset is NET_IP_ALIGN + reg->off (18)
* which is 20. Then the variable offset is (4n), so
* the total offset is 4-byte aligned and meets the
* load's requirements.
*/
- {33, "R4=pkt(id=4,off=22,r=22,umax_value=2040,var_off=(0x0; 0x7fc))"},
- {33, "R5=pkt(id=4,off=18,r=22,umax_value=2040,var_off=(0x0; 0x7fc))"},
+ {33, "R4=pkt(id=4,off=22,r=22,umax_value=2040,var_off=(0x0; 0x7fc)"},
+ {33, "R5=pkt(id=4,off=18,r=22,umax_value=2040,var_off=(0x0; 0x7fc)"},
},
},
{
@@ -410,15 +410,15 @@ static struct bpf_align_test tests[] = {
/* Adding 14 makes R6 be (4n+2) */
{9, "R6_w=inv(id=0,umin_value=14,umax_value=1034,var_off=(0x2; 0x7fc))"},
/* Packet pointer has (4n+2) offset */
- {11, "R5_w=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))"},
+ {11, "R5_w=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))"},
+ {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.
*/
@@ -426,15 +426,15 @@ static struct bpf_align_test tests[] = {
/* Added (4n) to packet pointer's (4n+2) var_off, giving
* another (4n+2).
*/
- {19, "R5_w=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))"},
+ {19, "R5_w=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))"},
+ {23, "R5=pkt(id=2,off=0,r=4,umin_value=14,umax_value=2054,var_off=(0x2; 0xffc)"},
},
},
{
@@ -469,11 +469,11 @@ static struct bpf_align_test tests[] = {
.matches = {
{4, "R5_w=pkt_end(id=0,off=0,imm=0)"},
/* (ptr - ptr) << 2 == unknown, (4n) */
- {6, "R5_w=inv(id=0,smax_value=9223372036854775804,umax_value=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc))"},
+ {6, "R5_w=inv(id=0,smax_value=9223372036854775804,umax_value=18446744073709551612,var_off=(0x0; 0xfffffffffffffffc)"},
/* (4n) + 14 == (4n+2). We blow our bounds, because
* the add could overflow.
*/
- {7, "R5=inv(id=0,var_off=(0x2; 0xfffffffffffffffc))"},
+ {7, "R5=inv(id=0,smin_value=-9223372036854775806,smax_value=9223372036854775806,umin_value=2,umax_value=18446744073709551614,var_off=(0x2; 0xfffffffffffffffc)"},
/* Checked s>=0 */
{9, "R5=inv(id=0,umin_value=2,umax_value=9223372036854775806,var_off=(0x2; 0x7ffffffffffffffc))"},
/* packet pointer + nonnegative (4n+2) */
@@ -528,7 +528,7 @@ static struct bpf_align_test tests[] = {
/* New unknown value in R7 is (4n) */
{11, "R7_w=inv(id=0,umax_value=1020,var_off=(0x0; 0x3fc))"},
/* Subtracting it from R6 blows our unsigned bounds */
- {12, "R6=inv(id=0,smin_value=-1006,smax_value=1034,var_off=(0x2; 0xfffffffffffffffc))"},
+ {12, "R6=inv(id=0,smin_value=-1006,smax_value=1034,umin_value=2,umax_value=18446744073709551614,var_off=(0x2; 0xfffffffffffffffc)"},
/* Checked s>= 0 */
{14, "R6=inv(id=0,umin_value=2,umax_value=1034,var_off=(0x2; 0x7fc))"},
/* At the time the word size load is performed from R5,
@@ -537,7 +537,8 @@ static struct bpf_align_test tests[] = {
* the total offset is 4-byte aligned and meets the
* load's requirements.
*/
- {20, "R5=pkt(id=1,off=0,r=4,umin_value=2,umax_value=1034,var_off=(0x2; 0x7fc))"},
+ {20, "R5=pkt(id=1,off=0,r=4,umin_value=2,umax_value=1034,var_off=(0x2; 0x7fc)"},
+
},
},
{
--
2.37.2
^ permalink raw reply related [flat|nested] 4+ messages in thread