This patch adds new selftests in the direct packet access suite, to
cover the non-linear case with BPF_F_TEST_SKB_NON_LINEAR. The three
first tests cover the behavior of the bounds check with a non-linear
skb (first two with min. linear size, third with long enough linear
size). The last test adds a call to bpf_skb_pull_data() to be able to
access the packet.
Signed-off-by: Paul Chaignon <paul.chaignon@xxxxxxxxx>
---
.../bpf/progs/verifier_direct_packet_access.c | 53 +++++++++++++++++++
1 file changed, 53 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/verifier_direct_packet_access.c b/tools/testing/selftests/bpf/progs/verifier_direct_packet_access.c
index a61897e01a50..595b9cb904ea 100644
--- a/tools/testing/selftests/bpf/progs/verifier_direct_packet_access.c
+++ b/tools/testing/selftests/bpf/progs/verifier_direct_packet_access.c
@@ -801,4 +801,57 @@ l0_%=: /* exit(0) */ \
: __clobber_all);
}
+#define access_test_non_linear(name, desc, retval, linear_sz) \
+ SEC("tc") \
+ __description("direct packet access: " #name " (non-linear, " desc ")") \
+ __success __retval(retval) \
+ __linear_size(linear_sz) \
+ __naked void access_##name(void) \
+ { \
+ asm volatile (" \
+ r2 = *(u32*)(r1 + %[skb_data]); \
+ r3 = *(u32*)(r1 + %[skb_data_end]); \
+ r0 = r2; \
+ r0 += 22; \
+ if r0 > r3 goto l0_%=; \
+ r0 = *(u8*)(r0 - 1); \
+ exit; \
+ l0_%=: r0 = 1; \
+ exit; \
+ " : \
+ : __imm_const(skb_data, offsetof(struct __sk_buff, data)), \
+ __imm_const(skb_data_end, offsetof(struct __sk_buff, data_end)) \
+ : __clobber_all); \
+ }
+
+access_test_non_linear(test31, "too short", 1, ETH_HLEN);
+access_test_non_linear(test32, "too short", 1, 1);
+access_test_non_linear(test33, "long enough", 0, 22);
+
+SEC("tc")
+__description("direct packet access: test34 (non-linear, linearized)")
+__success __retval(0)
+__linear_size(ETH_HLEN)
+__naked void access_test34_non_linear_linearized(void)
+{
+ asm volatile (" \
+ r6 = r1; \
+ r2 = 22; \
+ call %[bpf_skb_pull_data]; \
+ r2 = *(u32*)(r6 + %[skb_data]); \
+ r3 = *(u32*)(r6 + %[skb_data_end]); \
+ r0 = r2; \
+ r0 += 22; \
+ if r0 > r3 goto l0_%=; \
+ r0 = *(u8*)(r0 - 1); \
+ exit; \
+l0_%=: r0 = 1; \
+ exit; \
+" :
+ : __imm(bpf_skb_pull_data),
+ __imm_const(skb_data, offsetof(struct __sk_buff, data)),
+ __imm_const(skb_data_end, offsetof(struct __sk_buff, data_end))
+ : __clobber_all);
+}
+
char _license[] SEC("license") = "GPL";
--
2.43.0
