This patchset updates __reg_combine_64_into_32 function to set 32-bit bounds when lower 32-bit value is not wrapping, and add cases to for it.
Xu Kuohai (2): bpf: update 32-bit bounds when the lower 32-bit value is not wrapping selftests/bpf: check bounds not in the 32-bit range
kernel/bpf/verifier.c | 27 ++-- tools/testing/selftests/bpf/verifier/bounds.c | 121 ++++++++++++++++++ 2 files changed, 132 insertions(+), 16 deletions(-)
The following XDP prog is accepted by verifier.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+6 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (b4) w0 = 0x7fffff10 7: (0c) w1 += w0 ; R1_w=scalar(umin=0x7fffff10,umax=0x8000000f,var_off=(0x0; 0xffffffff)) 8: (b4) w0 = 0x80000000 9: (04) w0 += 1 10: (ae) if w0 < w1 goto pc-2 11: (b7) r0 = 0 12: (95) exit
while the following 64-bit version is rejected.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+8 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (18) r0 = 0x7fffffffffffff10 8: (0f) r1 += r0 ; R1_w=scalar(umin=0x7fffffffffffff10,umax=0x800000000000000f) 9: (18) r0 = 0x8000000000000000 11: (07) r0 += 1 12: (ad) if r0 < r1 goto pc-2 13: (b7) r0 = 0 14: (95) exit
The verifier log says:
[...]
from 12 to 11: R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 11: (07) r0 += 1 ; R0_w=-9223372036854775793 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
from 12 to 11: R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 11: (07) r0 += 1 ; R0_w=-9223372036854775792 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775792 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
[...]
The loop crosses termination condition r0 == r1.umax, and does not stop.
The reason is that when the verifier enumerates to r1.umin == r1.umax, the value 0x800000000000000f of r1.umin is greater than U32_MAX, so __reg_combine_64_into_32 sets the u32 range of r1 to [0, U32_MAX] instead of marking r1 as a constant, making is_branch_taken() in check_cond_jmp_op() be skipped.
To fix it, update 32-bit bounds when the lower 32-bit value is not wrapping, even if the 64-bit value is beyond the range of [0, U32_MAX] or [S32_MIN, S32_MAX].
Signed-off-by: Xu Kuohai xukuohai@huaweicloud.com --- kernel/bpf/verifier.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b2116ca78d9a..64c9ee3857ec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2013,26 +2013,21 @@ static void __reg_combine_32_into_64(struct bpf_reg_state *reg) reg_bounds_sync(reg); }
-static bool __reg64_bound_s32(s64 a) -{ - return a >= S32_MIN && a <= S32_MAX; -} - -static bool __reg64_bound_u32(u64 a) -{ - return a >= U32_MIN && a <= U32_MAX; -} - static void __reg_combine_64_into_32(struct bpf_reg_state *reg) { + s64 smin = reg->smin_value; + s64 smax = reg->smax_value; + u64 umin = reg->umin_value; + u64 umax = reg->umax_value; + __mark_reg32_unbounded(reg); - if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) { - reg->s32_min_value = (s32)reg->smin_value; - reg->s32_max_value = (s32)reg->smax_value; + if ((u64)(smax - smin) <= (u64)U32_MAX && (s32)smin <= (s32)smax) { + reg->s32_min_value = (s32)smin; + reg->s32_max_value = (s32)smax; } - if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) { - reg->u32_min_value = (u32)reg->umin_value; - reg->u32_max_value = (u32)reg->umax_value; + if (umax - umin <= U32_MAX && (u32)umin <= (u32)umax) { + reg->u32_min_value = (u32)umin; + reg->u32_max_value = (u32)umax; } reg_bounds_sync(reg); }
On 3/8/2023 6:04 AM, Xu Kuohai wrote:
The following XDP prog is accepted by verifier.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+6 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (b4) w0 = 0x7fffff10 7: (0c) w1 += w0 ; R1_w=scalar(umin=0x7fffff10,umax=0x8000000f,var_off=(0x0; 0xffffffff)) 8: (b4) w0 = 0x80000000 9: (04) w0 += 1 10: (ae) if w0 < w1 goto pc-2 11: (b7) r0 = 0 12: (95) exit
while the following 64-bit version is rejected.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+8 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (18) r0 = 0x7fffffffffffff10 8: (0f) r1 += r0 ; R1_w=scalar(umin=0x7fffffffffffff10,umax=0x800000000000000f) 9: (18) r0 = 0x8000000000000000 11: (07) r0 += 1 12: (ad) if r0 < r1 goto pc-2 13: (b7) r0 = 0 14: (95) exit
The verifier log says:
[...]
from 12 to 11: R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 11: (07) r0 += 1 ; R0_w=-9223372036854775793 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
from 12 to 11: R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 11: (07) r0 += 1 ; R0_w=-9223372036854775792 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775792 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
[...]
The loop crosses termination condition r0 == r1.umax, and does not stop.
The reason is that when the verifier enumerates to r1.umin == r1.umax, the value 0x800000000000000f of r1.umin is greater than U32_MAX, so __reg_combine_64_into_32 sets the u32 range of r1 to [0, U32_MAX] instead of marking r1 as a constant, making is_branch_taken() in check_cond_jmp_op() be skipped.
To fix it, update 32-bit bounds when the lower 32-bit value is not wrapping, even if the 64-bit value is beyond the range of [0, U32_MAX] or [S32_MIN, S32_MAX].
Signed-off-by: Xu Kuohai xukuohai@huaweicloud.com
Oops, missing fixes tag, will resend
kernel/bpf/verifier.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b2116ca78d9a..64c9ee3857ec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2013,26 +2013,21 @@ static void __reg_combine_32_into_64(struct bpf_reg_state *reg) reg_bounds_sync(reg); } -static bool __reg64_bound_s32(s64 a) -{
- return a >= S32_MIN && a <= S32_MAX;
-}
-static bool __reg64_bound_u32(u64 a) -{
- return a >= U32_MIN && a <= U32_MAX;
-}
- static void __reg_combine_64_into_32(struct bpf_reg_state *reg) {
- s64 smin = reg->smin_value;
- s64 smax = reg->smax_value;
- u64 umin = reg->umin_value;
- u64 umax = reg->umax_value;
- __mark_reg32_unbounded(reg);
- if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {
reg->s32_min_value = (s32)reg->smin_value;reg->s32_max_value = (s32)reg->smax_value;
- if ((u64)(smax - smin) <= (u64)U32_MAX && (s32)smin <= (s32)smax) {
reg->s32_min_value = (s32)smin;reg->s32_max_value = (s32)smax;
- if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {
reg->u32_min_value = (u32)reg->umin_value;reg->u32_max_value = (u32)reg->umax_value;
- if (umax - umin <= U32_MAX && (u32)umin <= (u32)umax) {
reg->u32_min_value = (u32)umin;reg->u32_max_value = (u32)umax;
On Tue, Mar 7, 2023 at 1:05 AM Xu Kuohai xukuohai@huaweicloud.com wrote:
The following XDP prog is accepted by verifier.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+6 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (b4) w0 = 0x7fffff10 7: (0c) w1 += w0 ; R1_w=scalar(umin=0x7fffff10,umax=0x8000000f,var_off=(0x0; 0xffffffff)) 8: (b4) w0 = 0x80000000 9: (04) w0 += 1 10: (ae) if w0 < w1 goto pc-2 11: (b7) r0 = 0 12: (95) exit
while the following 64-bit version is rejected.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+8 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (18) r0 = 0x7fffffffffffff10 8: (0f) r1 += r0 ; R1_w=scalar(umin=0x7fffffffffffff10,umax=0x800000000000000f) 9: (18) r0 = 0x8000000000000000 11: (07) r0 += 1 12: (ad) if r0 < r1 goto pc-2 13: (b7) r0 = 0 14: (95) exit
These two programs are not equivalent. Not clear how apples to oranges comparison explains anything.
The verifier log says:
[...]
from 12 to 11: R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 11: (07) r0 += 1 ; R0_w=-9223372036854775793 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
from 12 to 11: R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff))
First thing to debug is why umin is higher than umax.
11: (07) r0 += 1 ; R0_w=-9223372036854775792 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775792 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
[...]
The loop crosses termination condition r0 == r1.umax, and does not stop.
The reason is that when the verifier enumerates to r1.umin == r1.umax, the value 0x800000000000000f of r1.umin is greater than U32_MAX, so __reg_combine_64_into_32 sets the u32 range of r1 to [0, U32_MAX] instead of marking r1 as a constant, making is_branch_taken() in check_cond_jmp_op() be skipped.
And it's fine. The verifier is conservative.
To fix it, update 32-bit bounds when the lower 32-bit value is not wrapping, even if the 64-bit value is beyond the range of [0, U32_MAX] or [S32_MIN, S32_MAX].
That's not safe in general.
Signed-off-by: Xu Kuohai xukuohai@huaweicloud.com
kernel/bpf/verifier.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b2116ca78d9a..64c9ee3857ec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2013,26 +2013,21 @@ static void __reg_combine_32_into_64(struct bpf_reg_state *reg) reg_bounds_sync(reg); }
-static bool __reg64_bound_s32(s64 a) -{
return a >= S32_MIN && a <= S32_MAX;-}
-static bool __reg64_bound_u32(u64 a) -{
return a >= U32_MIN && a <= U32_MAX;-}
static void __reg_combine_64_into_32(struct bpf_reg_state *reg) {
s64 smin = reg->smin_value;s64 smax = reg->smax_value;u64 umin = reg->umin_value;u64 umax = reg->umax_value;__mark_reg32_unbounded(reg);
if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {reg->s32_min_value = (s32)reg->smin_value;reg->s32_max_value = (s32)reg->smax_value;
if ((u64)(smax - smin) <= (u64)U32_MAX && (s32)smin <= (s32)smax) {reg->s32_min_value = (s32)smin;reg->s32_max_value = (s32)smax; }
if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {reg->u32_min_value = (u32)reg->umin_value;reg->u32_max_value = (u32)reg->umax_value;
if (umax - umin <= U32_MAX && (u32)umin <= (u32)umax) {reg->u32_min_value = (u32)umin;reg->u32_max_value = (u32)umax;
This looks like a workaround for umin > umax issue. Please debug that instead.
} reg_bounds_sync(reg);}
2.30.2
On 3/8/2023 1:22 AM, Alexei Starovoitov wrote:
On Tue, Mar 7, 2023 at 1:05 AM Xu Kuohai xukuohai@huaweicloud.com wrote:
The following XDP prog is accepted by verifier.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+6 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (b4) w0 = 0x7fffff10 7: (0c) w1 += w0 ; R1_w=scalar(umin=0x7fffff10,umax=0x8000000f,var_off=(0x0; 0xffffffff)) 8: (b4) w0 = 0x80000000 9: (04) w0 += 1 10: (ae) if w0 < w1 goto pc-2 11: (b7) r0 = 0 12: (95) exit
while the following 64-bit version is rejected.
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0) 1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0) 2: (bf) r1 = r2 3: (07) r1 += 1 4: (2d) if r1 > r3 goto pc+8 5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) 6: (18) r0 = 0x7fffffffffffff10 8: (0f) r1 += r0 ; R1_w=scalar(umin=0x7fffffffffffff10,umax=0x800000000000000f) 9: (18) r0 = 0x8000000000000000 11: (07) r0 += 1 12: (ad) if r0 < r1 goto pc-2 13: (b7) r0 = 0 14: (95) exit
These two programs are not equivalent. Not clear how apples to oranges comparison explains anything.
Yes, they are not equivalent. I assumed the 32-bit prog being accepted implies it is unreasonable for the 64-bit prog to be rejected. Regardless of this assumption and the 32-bit prog, the above 64-bit prog is expected to be accepted, right?
The verifier log says:
[...]
from 12 to 11: R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 11: (07) r0 += 1 ; R0_w=-9223372036854775793 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
from 12 to 11: R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff))
First thing to debug is why umin is higher than umax.
Well, it's because the loop does not stop, when r0 increases to -9223372036854775793, the following code in reg_set_min_max() sets umin_value to 9223372036854775824:
case BPF_JGT: { if (is_jmp32) { [...] } else { u64 false_umax = opcode == BPF_JGT ? val : val - 1; u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
false_reg->umax_value = min(false_reg->umax_value, false_umax); true_reg->umin_value = max(true_reg->umin_value, true_umin); } break; }
To avoid umin > umax, it could be changed it to:
case BPF_JGT: { if (is_jmp32) { [...] } else { u64 false_umax = opcode == BPF_JGT ? val : val - 1; u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
false_reg->umax_value = min(false_reg->umax_value, false_umax); false_reg->umax_value = max(false_reg->umax_value, false_reg->umin_value);
true_reg->umin_value = max(true_reg->umin_value, true_umin); true_reg->umin_value = min(true_reg->umax_value, true_reg->umin_value); } break; }
The problem is that the loop still does not stop because tnum_is_const(src_reg->var_off) always returns false and is_branch_taken() is skipped:
if (BPF_SRC(insn->code) == BPF_K) { [...] } else if (src_reg->type == SCALAR_VALUE && is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) { [...] } else if (src_reg->type == SCALAR_VALUE && !is_jmp32 && tnum_is_const(src_reg->var_off)) { pred = is_branch_taken(dst_reg, // could not reach here src_reg->var_off.value, opcode, is_jmp32); } else if (reg_is_pkt_pointer_any(dst_reg) && reg_is_pkt_pointer_any(src_reg) && !is_jmp32) { [...] }
Why tnum_is_const(src_reg->var_off) returns false is because the lower 32-bit is not constant since the lower 32-bit range is [U32_MIN, U32_MAX].
11: (07) r0 += 1 ; R0_w=-9223372036854775792 12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775792 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) 13: safe
[...]
The loop crosses termination condition r0 == r1.umax, and does not stop.
The reason is that when the verifier enumerates to r1.umin == r1.umax, the value 0x800000000000000f of r1.umin is greater than U32_MAX, so __reg_combine_64_into_32 sets the u32 range of r1 to [0, U32_MAX] instead of marking r1 as a constant, making is_branch_taken() in check_cond_jmp_op() be skipped.
And it's fine. The verifier is conservative.
To fix it, update 32-bit bounds when the lower 32-bit value is not wrapping, even if the 64-bit value is beyond the range of [0, U32_MAX] or [S32_MIN, S32_MAX].
That's not safe in general.
Signed-off-by: Xu Kuohai xukuohai@huaweicloud.com
kernel/bpf/verifier.c | 27 +++++++++++---------------- 1 file changed, 11 insertions(+), 16 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b2116ca78d9a..64c9ee3857ec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2013,26 +2013,21 @@ static void __reg_combine_32_into_64(struct bpf_reg_state *reg) reg_bounds_sync(reg); }
-static bool __reg64_bound_s32(s64 a) -{
return a >= S32_MIN && a <= S32_MAX;-}
-static bool __reg64_bound_u32(u64 a) -{
return a >= U32_MIN && a <= U32_MAX;-}
- static void __reg_combine_64_into_32(struct bpf_reg_state *reg) {
s64 smin = reg->smin_value;s64 smax = reg->smax_value;u64 umin = reg->umin_value;u64 umax = reg->umax_value;__mark_reg32_unbounded(reg);
if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {reg->s32_min_value = (s32)reg->smin_value;reg->s32_max_value = (s32)reg->smax_value;
if ((u64)(smax - smin) <= (u64)U32_MAX && (s32)smin <= (s32)smax) {reg->s32_min_value = (s32)smin;reg->s32_max_value = (s32)smax; }
if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {reg->u32_min_value = (u32)reg->umin_value;reg->u32_max_value = (u32)reg->umax_value;
if (umax - umin <= U32_MAX && (u32)umin <= (u32)umax) {reg->u32_min_value = (u32)umin;reg->u32_max_value = (u32)umax;This looks like a workaround for umin > umax issue. Please debug that instead.
"__reg64_bound_u32(umin) && __reg64_bound_u32(max)" is a special case of "umax - umin <= U32_MAX && (u32)umin <= (u32)umax " when umax <= U32_MAX.
If it's only safe to set lower 32-bit range to [U32_MIN, U32_MAX] when umax > U32_MAX, could we infer the 64-bit value is a constant from umin == umax?
} reg_bounds_sync(reg);}
2.30.2
.
Add cases to check if bound is updated correctly when 64-bit value is not in the 32-bit range.
Signed-off-by: Xu Kuohai xukuohai@huaweicloud.com --- tools/testing/selftests/bpf/verifier/bounds.c | 121 ++++++++++++++++++ 1 file changed, 121 insertions(+)
diff --git a/tools/testing/selftests/bpf/verifier/bounds.c b/tools/testing/selftests/bpf/verifier/bounds.c index 33125d5f6772..74b1917d4208 100644 --- a/tools/testing/selftests/bpf/verifier/bounds.c +++ b/tools/testing/selftests/bpf/verifier/bounds.c @@ -753,3 +753,124 @@ .result_unpriv = REJECT, .result = ACCEPT, }, +{ + "bound check with JMP_JLT for crossing 64-bit signed boundary", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)), + 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, 1), + BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 8), + + BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0), + BPF_LD_IMM64(BPF_REG_0, 0x7fffffffffffff10), + BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0), + + BPF_LD_IMM64(BPF_REG_0, 0x8000000000000000), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1), + /* r1 unsigned range is [0x7fffffffffffff10, 0x800000000000000f] */ + BPF_JMP_REG(BPF_JLT, BPF_REG_0, BPF_REG_1, -2), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_XDP, +}, +{ + "bound check with JMP_JSLT for crossing 64-bit signed boundary", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)), + 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, 1), + BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 8), + + BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0), + BPF_LD_IMM64(BPF_REG_0, 0x7fffffffffffff10), + BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0), + + BPF_LD_IMM64(BPF_REG_0, 0x8000000000000000), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1), + /* r1 signed range is [S64_MIN, S64_MAX] */ + BPF_JMP_REG(BPF_JSLT, BPF_REG_0, BPF_REG_1, -2), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .errstr = "BPF program is too large", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_XDP, +}, +{ + "bound check for loop upper bound greater than U32_MAX", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)), + 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, 1), + BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 8), + + BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0), + BPF_LD_IMM64(BPF_REG_0, 0x100000000), + BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_0), + + BPF_LD_IMM64(BPF_REG_0, 0x100000000), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1), + BPF_JMP_REG(BPF_JLT, BPF_REG_0, BPF_REG_1, -2), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_XDP, +}, +{ + "bound check with JMP32_JLT for crossing 32-bit signed boundary", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)), + 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, 1), + BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 6), + + BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0), + BPF_MOV32_IMM(BPF_REG_0, 0x7fffff10), + BPF_ALU32_REG(BPF_ADD, BPF_REG_1, BPF_REG_0), + + BPF_MOV32_IMM(BPF_REG_0, 0x80000000), + BPF_ALU32_IMM(BPF_ADD, BPF_REG_0, 1), + /* r1 unsigned range is [0, 0x8000000f] */ + BPF_JMP32_REG(BPF_JLT, BPF_REG_0, BPF_REG_1, -2), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .result = ACCEPT, + .prog_type = BPF_PROG_TYPE_XDP, +}, +{ + "bound check with JMP32_JSLT for crossing 32-bit signed boundary", + .insns = { + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, offsetof(struct xdp_md, data)), + 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, 1), + BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_3, 6), + + BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0), + BPF_MOV32_IMM(BPF_REG_0, 0x7fffff10), + BPF_ALU32_REG(BPF_ADD, BPF_REG_1, BPF_REG_0), + + BPF_MOV32_IMM(BPF_REG_0, 0x80000000), + BPF_ALU32_IMM(BPF_ADD, BPF_REG_0, 1), + /* r1 signed range is [S32_MIN, S32_MAX] */ + BPF_JMP32_REG(BPF_JSLT, BPF_REG_0, BPF_REG_1, -2), + + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .errstr = "BPF program is too large", + .result = REJECT, + .prog_type = BPF_PROG_TYPE_XDP, +},
linux-kselftest-mirror@lists.linaro.org
-
Alexei Starovoitov -
Xu Kuohai -
Xu Kuohai