selftests/bpf: Extend verifier and bpf_sock tests for dst_port loads

commit 8f50f16ff39dd4e2d43d1548ca66925652f8aff7 upstream.

Add coverage to the verifier tests and tests for reading bpf_sock fields to
ensure that 32-bit, 16-bit, and 8-bit loads from dst_port field are allowed
only at intended offsets and produce expected values.

While 16-bit and 8-bit access to dst_port field is straight-forward, 32-bit
wide loads need be allowed and produce a zero-padded 16-bit value for
backward compatibility.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/r/20220130115518.213259-3-jakub@cloudflare.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[OP: backport to 5.4: cherry-pick verifier changes only]
Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jakub Sitnicki 2022-08-03 17:50:02 +03:00 committed by Greg Kroah-Hartman
parent 7c1134c7da
commit 751f05bc6f
2 changed files with 80 additions and 4 deletions

View File

@ -3068,7 +3068,8 @@ struct bpf_sock {
__u32 src_ip4;
__u32 src_ip6[4];
__u32 src_port; /* host byte order */
__u32 dst_port; /* network byte order */
__be16 dst_port; /* network byte order */
__u16 :16; /* zero padding */
__u32 dst_ip4;
__u32 dst_ip6[4];
__u32 state;

View File

@ -121,7 +121,25 @@
.result = ACCEPT,
},
{
"sk_fullsock(skb->sk): sk->dst_port [narrow load]",
"sk_fullsock(skb->sk): sk->dst_port [word load] (backward compatibility)",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct __sk_buff, sk)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, offsetof(struct bpf_sock, dst_port)),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = ACCEPT,
},
{
"sk_fullsock(skb->sk): sk->dst_port [half load]",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct __sk_buff, sk)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
@ -139,7 +157,7 @@
.result = ACCEPT,
},
{
"sk_fullsock(skb->sk): sk->dst_port [load 2nd byte]",
"sk_fullsock(skb->sk): sk->dst_port [half load] (invalid)",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct __sk_buff, sk)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
@ -149,7 +167,64 @@
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, offsetof(struct bpf_sock, dst_port) + 1),
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_0, offsetof(struct bpf_sock, dst_port) + 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = REJECT,
.errstr = "invalid sock access",
},
{
"sk_fullsock(skb->sk): sk->dst_port [byte load]",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct __sk_buff, sk)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_B, BPF_REG_2, BPF_REG_0, offsetof(struct bpf_sock, dst_port)),
BPF_LDX_MEM(BPF_B, BPF_REG_2, BPF_REG_0, offsetof(struct bpf_sock, dst_port) + 1),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = ACCEPT,
},
{
"sk_fullsock(skb->sk): sk->dst_port [byte load] (invalid)",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct __sk_buff, sk)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_0, offsetof(struct bpf_sock, dst_port) + 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
.result = REJECT,
.errstr = "invalid sock access",
},
{
"sk_fullsock(skb->sk): past sk->dst_port [half load] (invalid)",
.insns = {
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, offsetof(struct __sk_buff, sk)),
BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_0, offsetofend(struct bpf_sock, dst_port)),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},