Commit 7ec899ac authored by Paul Chaignon's avatar Paul Chaignon Committed by Andrii Nakryiko
Browse files

selftests/bpf: Negative test case for ref_obj_id in args 



This patch adds a test case, as shown below, for the verifier error
"more than one arg with ref_obj_id".

    0: (b7) r2 = 20
    1: (b7) r3 = 0
    2: (18) r1 = 0xffff92cee3cbc600
    4: (85) call bpf_ringbuf_reserve#131
    5: (55) if r0 == 0x0 goto pc+3
    6: (bf) r1 = r0
    7: (bf) r2 = r0
    8: (85) call bpf_tcp_raw_gen_syncookie_ipv4#204
    9: (95) exit

This error is currently incorrectly reported as a verifier bug, with a
warning. The next patch in this series will address that.

Signed-off-by: default avatarPaul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/3ba78e6cda47ccafd6ea70dadbc718d020154664.1751463262.git.paul.chaignon@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
parent a90f5f73

tools/testing/selftests/bpf/verifier/calls.c

+24 −0
Original line number Diff line number Diff line
@@ -2409,3 +2409,27 @@ 
	.errstr_unpriv = "",

	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,

},

{

	"calls: several args with ref_obj_id",

	.insns = {

	/* Reserve at least sizeof(struct iphdr) bytes in the ring buffer.

	 * With a smaller size, the verifier would reject the call to

	 * bpf_tcp_raw_gen_syncookie_ipv4 before we can reach the

	 * ref_obj_id error.

	 */

	BPF_MOV64_IMM(BPF_REG_2, 20),

	BPF_MOV64_IMM(BPF_REG_3, 0),

	BPF_LD_MAP_FD(BPF_REG_1, 0),

	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve),

	/* if r0 == 0 goto <exit> */

	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),

	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),

	BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),

	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_tcp_raw_gen_syncookie_ipv4),

	BPF_EXIT_INSN(),

	},

	.fixup_map_ringbuf = { 2 },

	.result = REJECT,

	.errstr = "more than one arg with ref_obj_id",

	.prog_type = BPF_PROG_TYPE_SCHED_CLS,

},