bpf: Support PTR_TO_MEM{,_OR_NULL} register spilling
Add support for pointer to mem register spilling, to allow the verifier
to track pointers to valid memory addresses. Such pointers are returned
for example by a successful call of the bpf_ringbuf_reserve helper.
The patch was partially contributed by CyberArk Software, Inc.
Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it")
Suggested-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Gilad Reti <gilad.reti@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210113053810.13518-1-gilad.reti@gmail.com
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 17270b8..36af69f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2217,6 +2217,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
case PTR_TO_RDWR_BUF:
case PTR_TO_RDWR_BUF_OR_NULL:
case PTR_TO_PERCPU_BTF_ID:
+ case PTR_TO_MEM:
+ case PTR_TO_MEM_OR_NULL:
return true;
default:
return false;
