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* SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user
@ 2019-03-01  1:06 Marek Majkowski
  2019-03-01 11:39 ` Arthur Fabre
  0 siblings, 1 reply; 6+ messages in thread
From: Marek Majkowski @ 2019-03-01  1:06 UTC (permalink / raw)
  To: ast, Daniel Borkmann, netdev

Howdy,

After some dramatic debugging, I think I managed to isolate a problem
that looks like a funny eBPF runtime regression. It seems to be
introduced somewhere after 4.14.

The eBPF in question is running on network sockets with
SO_ATTACH_BPF. The BPF_PROG_TYPE_SOCKET_FILTER code:

    uint64_t a = bpf_ktime_get_ns();
    uint64_t b = bpf_ktime_get_ns();
    uint64_t delta = b - a;
    if ((int64_t)delta > 0) {

Depending on a context, the "delta" variable is set to
a wrong value. The compiled bytecode seems fine:

Disassembly of section socket1:
bpf_prog1:
; {
       0:  85 00 00 00 05 00 00 00   call 5
; uint64_t a = bpf_ktime_get_ns();
       1:  bf 07 00 00 00 00 00 00   r7 = r0
; uint64_t b = bpf_ktime_get_ns();
       2:  85 00 00 00 05 00 00 00   call 5
       3:  bf 06 00 00 00 00 00 00   r6 = r0
; uint64_t delta = b - a;
       4:  bf 68 00 00 00 00 00 00   r8 = r6
       5:  1f 78 00 00 00 00 00 00   r8 -= r7
; if ((int64_t)delta > 0) {
       6:  b7 01 00 00 01 00 00 00   r1 = 1
       7:  6d 81 0a 00 00 00 00 00   if r1 s> r8 goto +10 XXX


The code runs fine from root. From unprivileged user though, the
value of "delta" is a wrapped negative. Both "a" and "b" are fine in
both root and non-root cases. Technically bpf_ktime_get_ns() can
go backwards, but this isn't the case here. It does seem like the
problem is with the behaiviour of ... the subtraction operation when
running from SO_ATTACH_BPF executed by non-root?

Code:
https://gist.github.com/majek/d0bb75a8c62cc35bec2b342054084aab

git clone https://gist.github.com/majek/d0bb75a8c62cc35bec2b342054084aab
cd d0bb75a8c62cc35bec2b342054084aab
make

Then:
$ sudo ./ebpf-bug
0 ->                    0 0x0000000000000000
1 ->       12585651690481 0x00000b72534c5bf1
2 ->       12585651690697 0x00000b72534c5cc9
3 ->                  216 0x00000000000000d8

$ ./ebpf-bug
0 ->                    1 0x0000000000000001
1 ->       12581437028489 0x00000b715815b889
2 ->       12581437028689 0x00000b715815b951
3 -> 18446731492272523127 0xfffff48ea7ea4777

"1" shows "a"
"2" shows "b"
"3" shows "detla"

As you see "delta" is off the scale for unprivileged user run. I
don't see any reason why root vs non-root should make any difference
for this code.

For completeness, this was tested with jit disabled:

$ cat /proc/version
Linux version 5.0.0-rc6+ (marek@mrbreeze) (gcc version 7.3.0)

$ sudo sysctl -a|grep -i jit
net.core.bpf_jit_enable = 0
net.core.bpf_jit_harden = 0

The same test on 4.14 seems fine:

$ cat /proc/version
Linux version 4.14.83-cloudflare-2018.11.4  (gcc version 8.2.0 (GCC))

$ sudo ./ebpf-bug
0 ->                    0 0x0000000000000000
1 ->     7435203111991321 0x001a6a472052b819
2 ->     7435203111991429 0x001a6a472052b885
3 ->                  108 0x000000000000006c

$ ./ebpf-bug
0 ->                    0 0x0000000000000000
1 ->     7435205114618775 0x001a6a4797b06397
2 ->     7435205114618883 0x001a6a4797b06403
3 ->                  108 0x000000000000006c

Cheers,
   Marek

^ permalink raw reply	[flat|nested] 6+ messages in thread

* RE: SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user
  2019-03-01  1:06 SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user Marek Majkowski
@ 2019-03-01 11:39 ` Arthur Fabre
  2019-03-01 12:51   ` Daniel Borkmann
  2019-03-01 14:04   ` Daniel Borkmann
  0 siblings, 2 replies; 6+ messages in thread
From: Arthur Fabre @ 2019-03-01 11:39 UTC (permalink / raw)
  To: marek; +Cc: ast, daniel, netdev, afabre

I can reproduce this on 4.19.0-3-amd64 both with, and without the JIT enabled.

Dumping the "root" and "non-root" programs with bpftool,
the subtraction instructions differ:

"non-root":
   0: (85) call bpf_ktime_get_ns#74944
   1: (bf) r7 = r0
   2: (85) call bpf_ktime_get_ns#74944
   3: (bf) r6 = r0
   4: (bf) r8 = r6
   5: (b4) w11 = -1
   6: (1f) r11 -= r8
   7: (4f) r11 |= r8
   8: (87) r11 = -r11
   9: (c7) r11 s>>= 63
  10: (5f) r8 &= r11

"root":
   0: (85) call bpf_ktime_get_ns#74944
   1: (bf) r7 = r0
   2: (85) call bpf_ktime_get_ns#74944
   3: (bf) r6 = r0
   4: (bf) r8 = r6

The remainder of the instructions are for writing the results in the map,
and the instructions are identical.

I believe the extra instructions come from "fixup_bpf_calls" in the verifier:

    if (isneg)
        *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
    *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
    *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
    *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
    *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
    *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
    if (issrc) {
        *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
                     off_reg);
        insn->src_reg = BPF_REG_AX;
    } else {
        *patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
                     BPF_REG_AX);
    }

This was introduced by "bpf: prevent out of bounds speculation on pointer arithmetic"
(https://patchwork.ozlabs.org/patch/1039606/).
I don't yet understand what's going on.

Cheers,

Arthur

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user
  2019-03-01 11:39 ` Arthur Fabre
@ 2019-03-01 12:51   ` Daniel Borkmann
  2019-03-01 14:04   ` Daniel Borkmann
  1 sibling, 0 replies; 6+ messages in thread
From: Daniel Borkmann @ 2019-03-01 12:51 UTC (permalink / raw)
  To: Arthur Fabre, marek; +Cc: ast, netdev

On 03/01/2019 12:39 PM, Arthur Fabre wrote:
> I can reproduce this on 4.19.0-3-amd64 both with, and without the JIT enabled.
> 
> Dumping the "root" and "non-root" programs with bpftool,
> the subtraction instructions differ:
> 
> "non-root":
>    0: (85) call bpf_ktime_get_ns#74944
>    1: (bf) r7 = r0
>    2: (85) call bpf_ktime_get_ns#74944
>    3: (bf) r6 = r0
>    4: (bf) r8 = r6
>    5: (b4) w11 = -1
>    6: (1f) r11 -= r8
>    7: (4f) r11 |= r8
>    8: (87) r11 = -r11
>    9: (c7) r11 s>>= 63
>   10: (5f) r8 &= r11
> 
> "root":
>    0: (85) call bpf_ktime_get_ns#74944
>    1: (bf) r7 = r0
>    2: (85) call bpf_ktime_get_ns#74944
>    3: (bf) r6 = r0
>    4: (bf) r8 = r6
> 
> The remainder of the instructions are for writing the results in the map,
> and the instructions are identical.
> 
> I believe the extra instructions come from "fixup_bpf_calls" in the verifier:
> 
>     if (isneg)
>         *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
>     *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
>     *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
>     *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
>     *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
>     *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
>     if (issrc) {
>         *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
>                      off_reg);
>         insn->src_reg = BPF_REG_AX;
>     } else {
>         *patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
>                      BPF_REG_AX);
>     }
> 
> This was introduced by "bpf: prevent out of bounds speculation on pointer arithmetic"
> (https://patchwork.ozlabs.org/patch/1039606/).
> I don't yet understand what's going on.

Hmm, thanks for the report, I'll take a look right away! There's no map
involved here it seems, so there shouldn't be such fixup.

Cheers,
Daniel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user
  2019-03-01 11:39 ` Arthur Fabre
  2019-03-01 12:51   ` Daniel Borkmann
@ 2019-03-01 14:04   ` Daniel Borkmann
  2019-03-01 14:10     ` Marek Majkowski
  1 sibling, 1 reply; 6+ messages in thread
From: Daniel Borkmann @ 2019-03-01 14:04 UTC (permalink / raw)
  To: Arthur Fabre, marek; +Cc: ast, netdev

On 03/01/2019 12:39 PM, Arthur Fabre wrote:
> I can reproduce this on 4.19.0-3-amd64 both with, and without the JIT enabled.
> 
> Dumping the "root" and "non-root" programs with bpftool,
> the subtraction instructions differ:
> 
> "non-root":
>    0: (85) call bpf_ktime_get_ns#74944
>    1: (bf) r7 = r0
>    2: (85) call bpf_ktime_get_ns#74944
>    3: (bf) r6 = r0
>    4: (bf) r8 = r6
>    5: (b4) w11 = -1
>    6: (1f) r11 -= r8
>    7: (4f) r11 |= r8
>    8: (87) r11 = -r11
>    9: (c7) r11 s>>= 63
>   10: (5f) r8 &= r11
> 
> "root":
>    0: (85) call bpf_ktime_get_ns#74944
>    1: (bf) r7 = r0
>    2: (85) call bpf_ktime_get_ns#74944
>    3: (bf) r6 = r0
>    4: (bf) r8 = r6
> 
> The remainder of the instructions are for writing the results in the map,
> and the instructions are identical.
> 
> I believe the extra instructions come from "fixup_bpf_calls" in the verifier:
> 
>     if (isneg)
>         *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
>     *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
>     *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
>     *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
>     *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
>     *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
>     if (issrc) {
>         *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
>                      off_reg);
>         insn->src_reg = BPF_REG_AX;
>     } else {
>         *patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
>                      BPF_REG_AX);
>     }
> 
> This was introduced by "bpf: prevent out of bounds speculation on pointer arithmetic"
> (https://patchwork.ozlabs.org/patch/1039606/).
> I don't yet understand what's going on.

Ok, sigh, fix is this, sorry about the braino:

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index cdd2cb01f789..5b3cd384df1d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7629,7 +7629,8 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
                        u32 off_reg;

                        aux = &env->insn_aux_data[i + delta];
-                       if (!aux->alu_state)
+                       if (!aux->alu_state ||
+                           aux->alu_state == BPF_ALU_NON_POINTER)
                                continue;

                        isneg = aux->alu_state & BPF_ALU_NEG_VALUE;

And this also makes the test work again:

foo@test:/root/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7$ ./ebpf-bug
0 ->                    0 0x0000000000000000
1 ->          54645145816 0x0000000cb91ac0d8
2 ->          54645145860 0x0000000cb91ac104
3 ->                   44 0x000000000000002c
foo@test:/root/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7$ exit
root@test:~/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7# ./ebpf-bug
0 ->                    0 0x0000000000000000
1 ->          57984017624 0x0000000d801de4d8
2 ->          57984017673 0x0000000d801de509
3 ->                   49 0x0000000000000031

I'll cook it as proper patch in a bit along with a test case.

Thanks for reporting!
Daniel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user
  2019-03-01 14:04   ` Daniel Borkmann
@ 2019-03-01 14:10     ` Marek Majkowski
  2019-03-01 14:22       ` Daniel Borkmann
  0 siblings, 1 reply; 6+ messages in thread
From: Marek Majkowski @ 2019-03-01 14:10 UTC (permalink / raw)
  To: Daniel Borkmann; +Cc: Arthur Fabre, ast, netdev

Great, appreciated.

One more thing (since upgrading kernels takes time) do you think I can
amend eBPF on my side to avoid triggering this? Naive stuff like this
doesn't work sadly:

    uint64_t delta = b + ~a + 1;

I tried couple more variants with uint32_t types, but to no avail. Ideas?

Marek

On Fri, Mar 1, 2019 at 3:04 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
>
> On 03/01/2019 12:39 PM, Arthur Fabre wrote:
> > I can reproduce this on 4.19.0-3-amd64 both with, and without the JIT enabled.
> >
> > Dumping the "root" and "non-root" programs with bpftool,
> > the subtraction instructions differ:
> >
> > "non-root":
> >    0: (85) call bpf_ktime_get_ns#74944
> >    1: (bf) r7 = r0
> >    2: (85) call bpf_ktime_get_ns#74944
> >    3: (bf) r6 = r0
> >    4: (bf) r8 = r6
> >    5: (b4) w11 = -1
> >    6: (1f) r11 -= r8
> >    7: (4f) r11 |= r8
> >    8: (87) r11 = -r11
> >    9: (c7) r11 s>>= 63
> >   10: (5f) r8 &= r11
> >
> > "root":
> >    0: (85) call bpf_ktime_get_ns#74944
> >    1: (bf) r7 = r0
> >    2: (85) call bpf_ktime_get_ns#74944
> >    3: (bf) r6 = r0
> >    4: (bf) r8 = r6
> >
> > The remainder of the instructions are for writing the results in the map,
> > and the instructions are identical.
> >
> > I believe the extra instructions come from "fixup_bpf_calls" in the verifier:
> >
> >     if (isneg)
> >         *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
> >     *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
> >     *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
> >     *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
> >     *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
> >     *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
> >     if (issrc) {
> >         *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
> >                      off_reg);
> >         insn->src_reg = BPF_REG_AX;
> >     } else {
> >         *patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
> >                      BPF_REG_AX);
> >     }
> >
> > This was introduced by "bpf: prevent out of bounds speculation on pointer arithmetic"
> > (https://patchwork.ozlabs.org/patch/1039606/).
> > I don't yet understand what's going on.
>
> Ok, sigh, fix is this, sorry about the braino:
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index cdd2cb01f789..5b3cd384df1d 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -7629,7 +7629,8 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
>                         u32 off_reg;
>
>                         aux = &env->insn_aux_data[i + delta];
> -                       if (!aux->alu_state)
> +                       if (!aux->alu_state ||
> +                           aux->alu_state == BPF_ALU_NON_POINTER)
>                                 continue;
>
>                         isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
>
> And this also makes the test work again:
>
> foo@test:/root/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7$ ./ebpf-bug
> 0 ->                    0 0x0000000000000000
> 1 ->          54645145816 0x0000000cb91ac0d8
> 2 ->          54645145860 0x0000000cb91ac104
> 3 ->                   44 0x000000000000002c
> foo@test:/root/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7$ exit
> root@test:~/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7# ./ebpf-bug
> 0 ->                    0 0x0000000000000000
> 1 ->          57984017624 0x0000000d801de4d8
> 2 ->          57984017673 0x0000000d801de509
> 3 ->                   49 0x0000000000000031
>
> I'll cook it as proper patch in a bit along with a test case.
>
> Thanks for reporting!
> Daniel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user
  2019-03-01 14:10     ` Marek Majkowski
@ 2019-03-01 14:22       ` Daniel Borkmann
  0 siblings, 0 replies; 6+ messages in thread
From: Daniel Borkmann @ 2019-03-01 14:22 UTC (permalink / raw)
  To: Marek Majkowski; +Cc: Arthur Fabre, ast, netdev

On 03/01/2019 03:10 PM, Marek Majkowski wrote:
> Great, appreciated.
> 
> One more thing (since upgrading kernels takes time) do you think I can
> amend eBPF on my side to avoid triggering this? Naive stuff like this
> doesn't work sadly:
> 
>     uint64_t delta = b + ~a + 1;
> 
> I tried couple more variants with uint32_t types, but to no avail. Ideas?

For 32bit based add/sub this would definitely not be triggered, but only
latest LLVM supports alu32 emission. Since you guys are using inline asm
already, perhaps worth a shot.

Thanks,
Daniel

> Marek
> 
> On Fri, Mar 1, 2019 at 3:04 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
>>
>> On 03/01/2019 12:39 PM, Arthur Fabre wrote:
>>> I can reproduce this on 4.19.0-3-amd64 both with, and without the JIT enabled.
>>>
>>> Dumping the "root" and "non-root" programs with bpftool,
>>> the subtraction instructions differ:
>>>
>>> "non-root":
>>>    0: (85) call bpf_ktime_get_ns#74944
>>>    1: (bf) r7 = r0
>>>    2: (85) call bpf_ktime_get_ns#74944
>>>    3: (bf) r6 = r0
>>>    4: (bf) r8 = r6
>>>    5: (b4) w11 = -1
>>>    6: (1f) r11 -= r8
>>>    7: (4f) r11 |= r8
>>>    8: (87) r11 = -r11
>>>    9: (c7) r11 s>>= 63
>>>   10: (5f) r8 &= r11
>>>
>>> "root":
>>>    0: (85) call bpf_ktime_get_ns#74944
>>>    1: (bf) r7 = r0
>>>    2: (85) call bpf_ktime_get_ns#74944
>>>    3: (bf) r6 = r0
>>>    4: (bf) r8 = r6
>>>
>>> The remainder of the instructions are for writing the results in the map,
>>> and the instructions are identical.
>>>
>>> I believe the extra instructions come from "fixup_bpf_calls" in the verifier:
>>>
>>>     if (isneg)
>>>         *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
>>>     *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit - 1);
>>>     *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
>>>     *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
>>>     *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
>>>     *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
>>>     if (issrc) {
>>>         *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX,
>>>                      off_reg);
>>>         insn->src_reg = BPF_REG_AX;
>>>     } else {
>>>         *patch++ = BPF_ALU64_REG(BPF_AND, off_reg,
>>>                      BPF_REG_AX);
>>>     }
>>>
>>> This was introduced by "bpf: prevent out of bounds speculation on pointer arithmetic"
>>> (https://patchwork.ozlabs.org/patch/1039606/).
>>> I don't yet understand what's going on.
>>
>> Ok, sigh, fix is this, sorry about the braino:
>>
>> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
>> index cdd2cb01f789..5b3cd384df1d 100644
>> --- a/kernel/bpf/verifier.c
>> +++ b/kernel/bpf/verifier.c
>> @@ -7629,7 +7629,8 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
>>                         u32 off_reg;
>>
>>                         aux = &env->insn_aux_data[i + delta];
>> -                       if (!aux->alu_state)
>> +                       if (!aux->alu_state ||
>> +                           aux->alu_state == BPF_ALU_NON_POINTER)
>>                                 continue;
>>
>>                         isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
>>
>> And this also makes the test work again:
>>
>> foo@test:/root/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7$ ./ebpf-bug
>> 0 ->                    0 0x0000000000000000
>> 1 ->          54645145816 0x0000000cb91ac0d8
>> 2 ->          54645145860 0x0000000cb91ac104
>> 3 ->                   44 0x000000000000002c
>> foo@test:/root/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7$ exit
>> root@test:~/d0bb75a8c62cc35bec2b342054084aab-7cc37a3a93c8b4028e977f3131feaf7f8705e6a7# ./ebpf-bug
>> 0 ->                    0 0x0000000000000000
>> 1 ->          57984017624 0x0000000d801de4d8
>> 2 ->          57984017673 0x0000000d801de509
>> 3 ->                   49 0x0000000000000031
>>
>> I'll cook it as proper patch in a bit along with a test case.
>>
>> Thanks for reporting!
>> Daniel


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2019-03-01 14:22 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-01  1:06 SOCKET_FILTER regression - eBPF can't subtract when attached from unprivileged user Marek Majkowski
2019-03-01 11:39 ` Arthur Fabre
2019-03-01 12:51   ` Daniel Borkmann
2019-03-01 14:04   ` Daniel Borkmann
2019-03-01 14:10     ` Marek Majkowski
2019-03-01 14:22       ` Daniel Borkmann

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