4 Commits

Author SHA1 Message Date
Hou Tao
b4b7a4099b selftests/bpf: Factor out get_xlated_program() helper
Both test_verifier and test_progs use get_xlated_program(), so moving
the helper into testing_helpers.h to reuse it.

Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20240105104819.3916743-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-23 14:40:21 -08:00
Jakub Kicinski
c0ba861117 net: skbuff: move the fields BPF cares about directly next to the offset marker
To avoid more possible BPF dependencies with moving bitfields
around keep the fields BPF cares about right next to the offset
marker.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230321014115.997841-4-kuba@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-20 21:57:49 -07:00
Jakub Kicinski
04aae213e7 net: skbuff: rename __pkt_vlan_present_offset to __mono_tc_offset
vlan_present is gone since
commit 354259fa73e2 ("net: remove skb->vlan_present")
rename the offset field to what BPF is currently looking
for in this byte - mono_delivery_time and tc_at_ingress.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20230321014115.997841-2-kuba@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
2023-03-20 21:57:49 -07:00
Eduard Zingerman
71cf4d027a selftests/bpf: Disassembler tests for verifier.c:convert_ctx_access()
Function verifier.c:convert_ctx_access() applies some rewrites to BPF
instructions that read or write BPF program context. This commit adds
machinery to allow test cases that inspect BPF program after these
rewrites are applied.

An example of a test case:

  {
        // Shorthand for field offset and size specification
	N(CGROUP_SOCKOPT, struct bpf_sockopt, retval),

        // Pattern generated for field read
	.read  = "$dst = *(u64 *)($ctx + bpf_sockopt_kern::current_task);"
		 "$dst = *(u64 *)($dst + task_struct::bpf_ctx);"
		 "$dst = *(u32 *)($dst + bpf_cg_run_ctx::retval);",

        // Pattern generated for field write
	.write = "*(u64 *)($ctx + bpf_sockopt_kern::tmp_reg) = r9;"
		 "r9 = *(u64 *)($ctx + bpf_sockopt_kern::current_task);"
		 "r9 = *(u64 *)(r9 + task_struct::bpf_ctx);"
		 "*(u32 *)(r9 + bpf_cg_run_ctx::retval) = $src;"
		 "r9 = *(u64 *)($ctx + bpf_sockopt_kern::tmp_reg);" ,
  },

For each test case, up to three programs are created:
- One that uses BPF_LDX_MEM to read the context field.
- One that uses BPF_STX_MEM to write to the context field.
- One that uses BPF_ST_MEM to write to the context field.

The disassembly of each program is compared with the pattern specified
in the test case.

Kernel code for disassembly is reused (as is in the bpftool).
To keep Makefile changes to the minimum, symbolic links to
`kernel/bpf/disasm.c` and `kernel/bpf/disasm.h ` are added.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230304011247.566040-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-03-03 21:41:46 -08:00