The bpf mirror of the in-kernel sk_buff and xdp_buff data structures are
__sk_buff and xdp_md. Currently, when we pass in the program ctx to a
kfunc where the program ctx is a skb or xdp buffer, we reject the
program if the in-kernel definition is sk_buff/xdp_buff instead of
__sk_buff/xdp_md.
This change allows sk_buff and __sk_buff, and xdp_buff and xdp_md to be
valid matches. The user program may pass in their program ctx as a
__sk_buff or xdp_md, and the in-kernel definition of the kfunc may
define this arg as a sk_buff or xdp_buff. Please note that the
__sk_buff/xdp_md -> sk_buff/xdp_buff conversion happens in
convert_ctx_accesses() in the verifier.
Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx>
---
kernel/bpf/btf.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 47b8cb96f2c2..b4da17688c65 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5606,6 +5606,10 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
* int socket_filter_bpf_prog(struct __sk_buff *skb)
* { // no fields of skb are ever used }
*/
+ if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0)
+ return ctx_type;
+ if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0)
+ return ctx_type;
if (strcmp(ctx_tname, tname))
return NULL;
return ctx_type;
--
2.30.2
