From c7b0e46bc2248643eb8a7c5f526c1a78069f968c Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 18 Jul 2023 13:29:12 -0700 Subject: [PATCH bpf-next] bpf, net: Introduce skb_pointer_if_linear. Signed-off-by: Alexei Starovoitov --- include/linux/skbuff.h | 10 +++++++++- kernel/bpf/helpers.c | 5 ++++- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 91ed66952580..f276d0e9816f 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -4023,7 +4023,7 @@ __skb_header_pointer(const struct sk_buff *skb, int offset, int len, if (likely(hlen - offset >= len)) return (void *)data + offset; - if (!skb || !buffer || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0)) + if (!skb || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0)) return NULL; return buffer; @@ -4036,6 +4036,14 @@ skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer) skb_headlen(skb), buffer); } +static inline void * __must_check +skb_pointer_if_linear(const struct sk_buff *skb, int offset, int len) +{ + if (likely(skb_headlen(skb) - offset >= len)) + return skb->data + offset; + return NULL; +} + /** * skb_needs_linearize - check if we need to linearize a given skb * depending on the given device features. diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 9e80efa59a5d..b8ab3bea71b7 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2239,7 +2239,10 @@ __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset case BPF_DYNPTR_TYPE_RINGBUF: return ptr->data + ptr->offset + offset; case BPF_DYNPTR_TYPE_SKB: - return skb_header_pointer(ptr->data, ptr->offset + offset, len, buffer__opt); + if (buffer__opt) + return skb_header_pointer(ptr->data, ptr->offset + offset, len, buffer__opt); + else + return skb_pointer_if_linear(ptr->data, ptr->offset + offset, len); case BPF_DYNPTR_TYPE_XDP: { void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset + offset, len); -- 2.34.1