From: Alexei Starovoitov Date: Tue, 18 Jul 2023 23:40:21 +0000 (-0700) Subject: bpf, net: Introduce skb_pointer_if_linear(). X-Git-Tag: v6.6.17~4098^2~371^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6f5a630d7c57cd79b1f526a95e757311e32d41e5;p=platform%2Fkernel%2Flinux-rpi.git bpf, net: Introduce skb_pointer_if_linear(). Network drivers always call skb_header_pointer() with non-null buffer. Remove !buffer check to prevent accidental misuse of skb_header_pointer(). Introduce skb_pointer_if_linear() instead. Reported-by: Jakub Kicinski Acked-by: Jakub Kicinski Link: https://lore.kernel.org/r/20230718234021.43640-1-alexei.starovoitov@gmail.com Signed-off-by: Alexei Starovoitov --- diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index ed83f1c..faaba05 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 bcff584..56ce500 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2263,7 +2263,10 @@ __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);