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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , Matthew Wilcox , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kuniyuki Iwashima Subject: [PATCH net-next v5 19/19] af_unix: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data Date: Thu, 6 Apr 2023 10:42:45 +0100 Message-Id: <20230406094245.3633290-20-dhowells@redhat.com> In-Reply-To: <20230406094245.3633290-1-dhowells@redhat.com> References: <20230406094245.3633290-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: nt9g6yo151wjzwfs17e15goghxhizc11 X-Rspamd-Queue-Id: 062D7C0011 X-HE-Tag: 1680774231-26584 X-HE-Meta: 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 4gY3cRfI I4MVq1qleIh3vnuTnBMNC7zCcHu+UFp35bn1+I01qFBLwKu4bF4jppO3QfvCY8kbpK3XYmeGNuMpHyoBcg3J1N8IfSMUIDiLiDIdCns8gk4DBWy0JkRdTws0XqcHRzaqSIEMw9/jrdKvRitwl8ypGK8QSdBVEr2moYJ/tRTFk0w4Pse8zSYQSrMJ7eFq7m3OyYFzSQ9o7LgEIDfA144zzKzDbCLqZsgKjhGwFofD8LArCC5pWbgh+8suhld1IzVNK2NCnP7MfvgjBsYdVisLVkP6nrpi7kLziGpqt1BX1R2Tk03bIs+eZdGQcCiVvlWzEzONceYVSg61fylj8lqhEABXmgrOC1KveuC/9Re63NSnTjdXPFGxleH8tXQ5n0jWAvqXBNFx3cXVMVll7ZEgcc9GXSwwSxY7eXjZQxtwxw0n3OFDjpiAw/SQK1FLUoHN7n/05i6HHcz0LHXxZ9r37vV96sPMWwfiWVm2UQxTRZOBt052Dpipv39GGBm4yQGl0ljDU3EGmhUxL3qJHeDxCz3RMPf6JoHBIVMBJzpoletf3VMZpEY1ch8Vp1ZYiP4CFB8JLV9OHjJwwr9I= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: If sendmsg() with MSG_SPLICE_PAGES encounters a page that shouldn't be spliced - a slab page, for instance, or one with a zero count - make unix_extract_bvec_to_skb() copy it. Signed-off-by: David Howells cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Kuniyuki Iwashima cc: Jens Axboe cc: Matthew Wilcox cc: netdev@vger.kernel.org --- net/unix/af_unix.c | 44 +++++++++++++++++++++++++++++++++----------- 1 file changed, 33 insertions(+), 11 deletions(-) diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index fee431a089d3..6941be8dae7e 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2160,12 +2160,12 @@ static int queue_oob(struct socket *sock, struct msghdr *msg, struct sock *other /* * Extract pages from an iterator and add them to the socket buffer. */ -static ssize_t unix_extract_bvec_to_skb(struct sk_buff *skb, - struct iov_iter *iter, ssize_t maxsize) +static ssize_t unix_extract_bvec_to_skb(struct sk_buff *skb, struct iov_iter *iter, + ssize_t maxsize, gfp_t gfp) { struct page *pages[8], **ppages = pages; unsigned int i, nr; - ssize_t ret = 0; + ssize_t spliced = 0, ret = 0; while (iter->count > 0) { size_t off, len; @@ -2177,31 +2177,52 @@ static ssize_t unix_extract_bvec_to_skb(struct sk_buff *skb, len = iov_iter_extract_pages(iter, &ppages, maxsize, nr, 0, &off); if (len <= 0) { - if (!ret) - ret = len ?: -EIO; + ret = len ?: -EIO; break; } i = 0; do { + struct page *page = pages[i++]; size_t part = min_t(size_t, PAGE_SIZE - off, len); + bool put = false; + + if (!sendpage_ok(page)) { + const void *p = kmap_local_page(page); + void *q; + + q = page_frag_memdup(NULL, p + off, part, gfp, + ULONG_MAX); + kunmap_local(p); + if (!q) { + iov_iter_revert(iter, len); + ret = -ENOMEM; + goto out; + } + page = virt_to_page(q); + off = offset_in_page(q); + put = true; + } - if (skb_append_pagefrags(skb, pages[i++], off, part) < 0) { - if (!ret) - ret = -EMSGSIZE; + ret = skb_append_pagefrags(skb, page, off, part); + if (put) + put_page(page); + if (ret < 0) { + iov_iter_revert(iter, len); goto out; } off = 0; - ret += part; + spliced += part; maxsize -= part; len -= part; } while (len > 0); + if (maxsize <= 0) break; } out: - return ret; + return spliced ?: ret; } static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, @@ -2278,7 +2299,8 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, fds_sent = true; if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) { - size = unix_extract_bvec_to_skb(skb, &msg->msg_iter, size); + size = unix_extract_bvec_to_skb(skb, &msg->msg_iter, size, + sk->sk_allocation); skb->data_len += size; skb->len += size; skb->truesize += size;