From 3bda08b63670c39be390fcb00e7718775508e673 Mon Sep 17 00:00:00 2001 From: Daniel Rosenberg Date: Fri, 5 May 2023 18:31:30 -0700 Subject: bpf: Allow NULL buffers in bpf_dynptr_slice(_rw) bpf_dynptr_slice(_rw) uses a user provided buffer if it can not provide a pointer to a block of contiguous memory. This buffer is unused in the case of local dynptrs, and may be unused in other cases as well. There is no need to require the buffer, as the kfunc can just return NULL if it was needed and not provided. This adds another kfunc annotation, __opt, which combines with __sz and __szk to allow the buffer associated with the size to be NULL. If the buffer is NULL, the verifier does not check that the buffer is of sufficient size. Signed-off-by: Daniel Rosenberg Link: https://lore.kernel.org/r/20230506013134.2492210-2-drosen@google.com Signed-off-by: Alexei Starovoitov --- include/linux/skbuff.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/skbuff.h') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 738776ab8838..8ddb4af1a501 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -4033,7 +4033,7 @@ __skb_header_pointer(const struct sk_buff *skb, int offset, int len, if (likely(hlen - offset >= len)) return (void *)data + offset; - if (!skb || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0)) + if (!skb || !buffer || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0)) return NULL; return buffer; -- cgit v1.2.3