[PATCH 5.10 09/43] bpf: Support PTR_TO_MEM{,_OR_NULL} register spilling

[Greg Kroah-Hartman]

From: Gilad Reti <gilad.r...@gmail.com>

commit 744ea4e3885eccb6d332a06fae9eb7420a622c0f upstream.

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 <y...@fb.com>
Signed-off-by: Gilad Reti <gilad.r...@gmail.com>
Signed-off-by: Alexei Starovoitov <a...@kernel.org>
Acked-by: KP Singh <kpsi...@kernel.org>
Link: https://lore.kernel.org/bpf/20210113053810.13518-1-gilad.r...@gmail.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 kernel/bpf/verifier.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2214,6 +2214,8 @@ static bool is_spillable_regtype(enum bp
        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;