diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-03-16 01:42:49 +0100 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:50:10 +0300 |
| commit | 1c4f960f2e7c97d21861c0132159f190adb2149e (patch) | |
| tree | 69fbc87e829433828dc90993b191d59415dfe5c4 | |
| parent | e8a3a06c6113522d937a844aa94a45ec70557abf (diff) | |
bpf: make skb->tc_classid also readable
Currently, the tc_classid from eBPF skb context is write-only, but there's
no good reason for tc programs to limit it to write-only. For example,
it can be used to transfer its state via tail calls where the resulting
tc_classid gets filled gradually.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
| -rw-r--r-- | net/core/filter.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index d1969447fd27..cf0bad6aca3a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2079,16 +2079,14 @@ static bool sk_filter_is_valid_access(int off, int size, static bool tc_cls_act_is_valid_access(int off, int size, enum bpf_access_type type) { - if (off == offsetof(struct __sk_buff, tc_classid)) - return type == BPF_WRITE ? true : false; - if (type == BPF_WRITE) { switch (off) { case offsetof(struct __sk_buff, mark): case offsetof(struct __sk_buff, tc_index): case offsetof(struct __sk_buff, priority): case offsetof(struct __sk_buff, cb[0]) ... - offsetof(struct __sk_buff, cb[4]): + offsetof(struct __sk_buff, cb[4]): + case offsetof(struct __sk_buff, tc_classid): break; default: return false; @@ -2205,8 +2203,10 @@ static u32 bpf_net_convert_ctx_access(enum bpf_access_type type, int dst_reg, ctx_off -= offsetof(struct __sk_buff, tc_classid); ctx_off += offsetof(struct sk_buff, cb); ctx_off += offsetof(struct qdisc_skb_cb, tc_classid); - WARN_ON(type != BPF_WRITE); - *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, ctx_off); + if (type == BPF_WRITE) + *insn++ = BPF_STX_MEM(BPF_H, dst_reg, src_reg, ctx_off); + else + *insn++ = BPF_LDX_MEM(BPF_H, dst_reg, src_reg, ctx_off); break; case offsetof(struct __sk_buff, tc_index): |