[PATCH bpf RESEND 2/4] bpf: Remove size check for sk in bpf_skb_is_valid_access for 32-bit architecture

[Yang Jihong]

The error code -EACCES is returned when bpf prog is tested in 32-bit environment,
This is because bpf_object__relocate modifies the instruction to change memory
size to 4 bytes, as shown in the following messages:

libbpf: prog 'kfunc_call_test1': relo #2: matching candidate #0 <byte_off> [18342] struct __sk_buff.sk (0:30:0 @ offset 168)
libbpf: prog 'kfunc_call_test1': relo #2: patched insn #1 (LDX/ST/STX) off 168 -> 168
libbpf: prog 'kfunc_call_test1': relo #2: patched insn #1 (LDX/ST/STX) mem_sz 8 -> 4

As a result, the bpf_skb_is_valid_access check fails. For 32-bit architecture,
unnecessary checks need to be deleted.

Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
---
 net/core/filter.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index bb0136e7a8e4..eab7ce89740c 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8269,8 +8269,6 @@ static bool bpf_skb_is_valid_access(int off, int size, enum bpf_access_type type
 			return false;
 		break;
 	case offsetof(struct __sk_buff, sk):
-		if (type == BPF_WRITE || size != sizeof(__u64))
-			return false;
 		info->reg_type = PTR_TO_SOCK_COMMON_OR_NULL;
 		break;
 	case offsetof(struct __sk_buff, tstamp_type):
-- 
2.30.GIT