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packetdrill: add coverage for RM_ADDR #167

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dcaratti opened this issue Feb 23, 2021 · 0 comments
Open

packetdrill: add coverage for RM_ADDR #167

dcaratti opened this issue Feb 23, 2021 · 0 comments
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enhancement packetdrill

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  • validation of inbound / outbound RM_ADDR
  • check functional compliance to RFC8684 §3.4.2
@dcaratti dcaratti self-assigned this Feb 23, 2021
dcaratti added a commit to dcaratti/packetdrill that referenced this issue Mar 25, 2021
@dcaratti
Add initial coverage for RM_ADDR
94e7247 
Link: multipath-tcp/mptcp_net-next#167
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
dcaratti added a commit to dcaratti/packetdrill that referenced this issue Mar 25, 2021
@dcaratti
Add initial coverage for RM_ADDR
5daec91 
Link: multipath-tcp/mptcp_net-next#167
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
@dcaratti dcaratti mentioned this issue Mar 31, 2021
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jenkins-tessares pushed a commit that referenced this issue Apr 29, 2021
@anakryiko
selftests/bpf: Fix BPF_CORE_READ_BITFIELD() macro
0f20615 
Fix BPF_CORE_READ_BITFIELD() macro used for reading CO-RE-relocatable
bitfields. Missing breaks in a switch caused 8-byte reads always. This can
confuse libbpf because it does strict checks that memory load size corresponds
to the original size of the field, which in this case quite often would be
wrong.

After fixing that, we run into another problem, which quite subtle, so worth
documenting here. The issue is in Clang optimization and CO-RE relocation
interactions. Without that asm volatile construct (also known as
barrier_var()), Clang will re-order BYTE_OFFSET and BYTE_SIZE relocations and
will apply BYTE_OFFSET 4 times for each switch case arm. This will result in
the same error from libbpf about mismatch of memory load size and original
field size. I.e., if we were reading u32, we'd still have *(u8 *), *(u16 *),
*(u32 *), and *(u64 *) memory loads, three of which will fail. Using
barrier_var() forces Clang to apply BYTE_OFFSET relocation first (and once) to
calculate p, after which value of p is used without relocation in each of
switch case arms, doing appropiately-sized memory load.

Here's the list of relevant relocations and pieces of generated BPF code
before and after this patch for test_core_reloc_bitfields_direct selftests.

BEFORE
=====
 #45: core_reloc: insn #160 --> [5] + 0:5: byte_sz --> struct core_reloc_bitfields.u32
 #46: core_reloc: insn #167 --> [5] + 0:5: byte_off --> struct core_reloc_bitfields.u32
 #47: core_reloc: insn #174 --> [5] + 0:5: byte_off --> struct core_reloc_bitfields.u32
 #48: core_reloc: insn #178 --> [5] + 0:5: byte_off --> struct core_reloc_bitfields.u32
 #49: core_reloc: insn #182 --> [5] + 0:5: byte_off --> struct core_reloc_bitfields.u32

     157:       18 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r2 = 0 ll
     159:       7b 12 20 01 00 00 00 00 *(u64 *)(r2 + 288) = r1
     160:       b7 02 00 00 04 00 00 00 r2 = 4
; BYTE_SIZE relocation here                 ^^^
     161:       66 02 07 00 03 00 00 00 if w2 s> 3 goto +7 <LBB0_63>
     162:       16 02 0d 00 01 00 00 00 if w2 == 1 goto +13 <LBB0_65>
     163:       16 02 01 00 02 00 00 00 if w2 == 2 goto +1 <LBB0_66>
     164:       05 00 12 00 00 00 00 00 goto +18 <LBB0_69>

0000000000000528 <LBB0_66>:
     165:       18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r1 = 0 ll
     167:       69 11 08 00 00 00 00 00 r1 = *(u16 *)(r1 + 8)
; BYTE_OFFSET relo here w/ WRONG size        ^^^^^^^^^^^^^^^^
     168:       05 00 0e 00 00 00 00 00 goto +14 <LBB0_69>

0000000000000548 <LBB0_63>:
     169:       16 02 0a 00 04 00 00 00 if w2 == 4 goto +10 <LBB0_67>
     170:       16 02 01 00 08 00 00 00 if w2 == 8 goto +1 <LBB0_68>
     171:       05 00 0b 00 00 00 00 00 goto +11 <LBB0_69>

0000000000000560 <LBB0_68>:
     172:       18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r1 = 0 ll
     174:       79 11 08 00 00 00 00 00 r1 = *(u64 *)(r1 + 8)
; BYTE_OFFSET relo here w/ WRONG size        ^^^^^^^^^^^^^^^^
     175:       05 00 07 00 00 00 00 00 goto +7 <LBB0_69>

0000000000000580 <LBB0_65>:
     176:       18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r1 = 0 ll
     178:       71 11 08 00 00 00 00 00 r1 = *(u8 *)(r1 + 8)
; BYTE_OFFSET relo here w/ WRONG size        ^^^^^^^^^^^^^^^^
     179:       05 00 03 00 00 00 00 00 goto +3 <LBB0_69>

00000000000005a0 <LBB0_67>:
     180:       18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r1 = 0 ll
     182:       61 11 08 00 00 00 00 00 r1 = *(u32 *)(r1 + 8)
; BYTE_OFFSET relo here w/ RIGHT size        ^^^^^^^^^^^^^^^^

00000000000005b8 <LBB0_69>:
     183:       67 01 00 00 20 00 00 00 r1 <<= 32
     184:       b7 02 00 00 00 00 00 00 r2 = 0
     185:       16 02 02 00 00 00 00 00 if w2 == 0 goto +2 <LBB0_71>
     186:       c7 01 00 00 20 00 00 00 r1 s>>= 32
     187:       05 00 01 00 00 00 00 00 goto +1 <LBB0_72>

00000000000005e0 <LBB0_71>:
     188:       77 01 00 00 20 00 00 00 r1 >>= 32

AFTER
=====

 #30: core_reloc: insn #132 --> [5] + 0:5: byte_off --> struct core_reloc_bitfields.u32
 #31: core_reloc: insn #134 --> [5] + 0:5: byte_sz --> struct core_reloc_bitfields.u32

     129:       18 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 r2 = 0 ll
     131:       7b 12 20 01 00 00 00 00 *(u64 *)(r2 + 288) = r1
     132:       b7 01 00 00 08 00 00 00 r1 = 8
; BYTE_OFFSET relo here                     ^^^
; no size check for non-memory dereferencing instructions
     133:       0f 12 00 00 00 00 00 00 r2 += r1
     134:       b7 03 00 00 04 00 00 00 r3 = 4
; BYTE_SIZE relocation here                 ^^^
     135:       66 03 05 00 03 00 00 00 if w3 s> 3 goto +5 <LBB0_63>
     136:       16 03 09 00 01 00 00 00 if w3 == 1 goto +9 <LBB0_65>
     137:       16 03 01 00 02 00 00 00 if w3 == 2 goto +1 <LBB0_66>
     138:       05 00 0a 00 00 00 00 00 goto +10 <LBB0_69>

0000000000000458 <LBB0_66>:
     139:       69 21 00 00 00 00 00 00 r1 = *(u16 *)(r2 + 0)
; NO CO-RE relocation here                   ^^^^^^^^^^^^^^^^
     140:       05 00 08 00 00 00 00 00 goto +8 <LBB0_69>

0000000000000468 <LBB0_63>:
     141:       16 03 06 00 04 00 00 00 if w3 == 4 goto +6 <LBB0_67>
     142:       16 03 01 00 08 00 00 00 if w3 == 8 goto +1 <LBB0_68>
     143:       05 00 05 00 00 00 00 00 goto +5 <LBB0_69>

0000000000000480 <LBB0_68>:
     144:       79 21 00 00 00 00 00 00 r1 = *(u64 *)(r2 + 0)
; NO CO-RE relocation here                   ^^^^^^^^^^^^^^^^
     145:       05 00 03 00 00 00 00 00 goto +3 <LBB0_69>

0000000000000490 <LBB0_65>:
     146:       71 21 00 00 00 00 00 00 r1 = *(u8 *)(r2 + 0)
; NO CO-RE relocation here                   ^^^^^^^^^^^^^^^^
     147:       05 00 01 00 00 00 00 00 goto +1 <LBB0_69>

00000000000004a0 <LBB0_67>:
     148:       61 21 00 00 00 00 00 00 r1 = *(u32 *)(r2 + 0)
; NO CO-RE relocation here                   ^^^^^^^^^^^^^^^^

00000000000004a8 <LBB0_69>:
     149:       67 01 00 00 20 00 00 00 r1 <<= 32
     150:       b7 02 00 00 00 00 00 00 r2 = 0
     151:       16 02 02 00 00 00 00 00 if w2 == 0 goto +2 <LBB0_71>
     152:       c7 01 00 00 20 00 00 00 r1 s>>= 32
     153:       05 00 01 00 00 00 00 00 goto +1 <LBB0_72>

00000000000004d0 <LBB0_71>:
     154:       77 01 00 00 20 00 00 00 r1 >>= 323

Fixes: ee26dad ("libbpf: Add support for relocatable bitfields")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Lorenz Bauer <lmb@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210426192949.416837-4-andrii@kernel.org
jenkins-tessares pushed a commit that referenced this issue Aug 14, 2021
@alexdeucher
drm/amdgpu: Fix out-of-bounds read when update mapping
4d77f36 
If one GTT BO has been evicted/swapped out, it should sit in CPU domain.
TTM only alloc struct ttm_resource instead of struct ttm_range_mgr_node
for sysMem.

Now when we update mapping for such invalidated BOs, we might walk out
of bounds of struct ttm_resource.

Three possible fix:
1) Let sysMem manager alloc struct ttm_range_mgr_node, like
ttm_range_manager does.
2) Pass pages_addr to update_mapping function too, but need memset
pages_addr[] to zero when unpopulate.
3) Init amdgpu_res_cursor directly.

bug is detected by kfence.
==================================================================
BUG: KFENCE: out-of-bounds read in amdgpu_vm_bo_update_mapping+0x564/0x6e0

Out-of-bounds read at 0x000000008ea93fe9 (64B right of kfence-#167):
 amdgpu_vm_bo_update_mapping+0x564/0x6e0 [amdgpu]
 amdgpu_vm_bo_update+0x282/0xa40 [amdgpu]
 amdgpu_vm_handle_moved+0x19e/0x1f0 [amdgpu]
 amdgpu_cs_vm_handling+0x4e4/0x640 [amdgpu]
 amdgpu_cs_ioctl+0x19e7/0x23c0 [amdgpu]
 drm_ioctl_kernel+0xf3/0x180 [drm]
 drm_ioctl+0x2cb/0x550 [drm]
 amdgpu_drm_ioctl+0x5e/0xb0 [amdgpu]

kfence-#167 [0x000000008e11c055-0x000000001f676b3e
 ttm_sys_man_alloc+0x35/0x80 [ttm]
 ttm_resource_alloc+0x39/0x50 [ttm]
 ttm_bo_swapout+0x252/0x5a0 [ttm]
 ttm_device_swapout+0x107/0x180 [ttm]
 ttm_global_swapout+0x6f/0x130 [ttm]
 ttm_tt_populate+0xb1/0x2a0 [ttm]
 ttm_bo_handle_move_mem+0x17e/0x1d0 [ttm]
 ttm_mem_evict_first+0x59d/0x9c0 [ttm]
 ttm_bo_mem_space+0x39f/0x400 [ttm]
 ttm_bo_validate+0x13c/0x340 [ttm]
 ttm_bo_init_reserved+0x269/0x540 [ttm]
 amdgpu_bo_create+0x1d1/0xa30 [amdgpu]
 amdgpu_bo_create_user+0x40/0x80 [amdgpu]
 amdgpu_gem_object_create+0x71/0xc0 [amdgpu]
 amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu+0x2f2/0xcd0 [amdgpu]
 kfd_ioctl_alloc_memory_of_gpu+0xe2/0x330 [amdgpu]
 kfd_ioctl+0x461/0x690 [amdgpu]

Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
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