From 6f26c9a7555e5bcca3560919db9b852015077dae Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Mon, 20 Apr 2009 01:26:11 +0000 Subject: [PATCH] tun: fix tun_chr_aio_write so that aio works aio_write gets const struct iovec * but tun_chr_aio_write casts this to struct iovec * and modifies the iovec. As a result, attempts to use io_submit to send packets to a tun device fail with weird errors such as EINVAL. Since tun is the only user of skb_copy_datagram_from_iovec, we can fix this simply by changing the later so that it does not touch the iovec passed to it. Signed-off-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/net/tun.c | 13 ++++++++----- include/linux/skbuff.h | 3 ++- include/linux/socket.h | 4 ++-- net/core/datagram.c | 20 ++++++++++++++------ net/core/iovec.c | 7 ++++--- 5 files changed, 30 insertions(+), 17 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 3b513e29d39..589f0ca668d 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -540,31 +540,34 @@ static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun, /* Get packet from user space buffer */ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, - struct iovec *iv, size_t count, + const struct iovec *iv, size_t count, int noblock) { struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) }; struct sk_buff *skb; size_t len = count, align = 0; struct virtio_net_hdr gso = { 0 }; + int offset = 0; if (!(tun->flags & TUN_NO_PI)) { if ((len -= sizeof(pi)) > count) return -EINVAL; - if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi))) + if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) return -EFAULT; + offset += sizeof(pi); } if (tun->flags & TUN_VNET_HDR) { if ((len -= sizeof(gso)) > count) return -EINVAL; - if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso))) + if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) return -EFAULT; if (gso.hdr_len > len) return -EINVAL; + offset += sizeof(pi); } if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) { @@ -581,7 +584,7 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, return PTR_ERR(skb); } - if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) { + if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) { tun->dev->stats.rx_dropped++; kfree_skb(skb); return -EFAULT; @@ -673,7 +676,7 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv, DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count); - result = tun_get_user(tun, (struct iovec *)iv, iov_length(iv, count), + result = tun_get_user(tun, iv, iov_length(iv, count), file->f_flags & O_NONBLOCK); tun_put(tun); diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index af2b21bdda8..1b5c3d298f4 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1715,7 +1715,8 @@ extern int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, struct iovec *iov); extern int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, - struct iovec *from, + const struct iovec *from, + int from_offset, int len); extern int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset, diff --git a/include/linux/socket.h b/include/linux/socket.h index 171b08db9c4..42a0396f2c5 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -309,8 +309,8 @@ struct ucred { #ifdef __KERNEL__ extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len); -extern int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, - int offset, int len); +extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov, + int offset, int len); extern int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset, diff --git a/net/core/datagram.c b/net/core/datagram.c index 4dbb05cd572..914d5fa773b 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -435,13 +435,15 @@ EXPORT_SYMBOL(skb_copy_datagram_const_iovec); * @skb: buffer to copy * @offset: offset in the buffer to start copying to * @from: io vector to copy to + * @from_offset: offset in the io vector to start copying from * @len: amount of data to copy to buffer from iovec * * Returns 0 or -EFAULT. - * Note: the iovec is modified during the copy. + * Note: the iovec is not modified during the copy. */ int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, - struct iovec *from, int len) + const struct iovec *from, int from_offset, + int len) { int start = skb_headlen(skb); int i, copy = start - offset; @@ -450,11 +452,12 @@ int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, if (copy > 0) { if (copy > len) copy = len; - if (memcpy_fromiovec(skb->data + offset, from, copy)) + if (memcpy_fromiovecend(skb->data + offset, from, 0, copy)) goto fault; if ((len -= copy) == 0) return 0; offset += copy; + from_offset += copy; } /* Copy paged appendix. Hmm... why does this look so complicated? */ @@ -473,8 +476,9 @@ int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, if (copy > len) copy = len; vaddr = kmap(page); - err = memcpy_fromiovec(vaddr + frag->page_offset + - offset - start, from, copy); + err = memcpy_fromiovecend(vaddr + frag->page_offset + + offset - start, + from, from_offset, copy); kunmap(page); if (err) goto fault; @@ -482,6 +486,7 @@ int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, if (!(len -= copy)) return 0; offset += copy; + from_offset += copy; } start = end; } @@ -500,11 +505,14 @@ int skb_copy_datagram_from_iovec(struct sk_buff *skb, int offset, copy = len; if (skb_copy_datagram_from_iovec(list, offset - start, - from, copy)) + from, + from_offset, + copy)) goto fault; if ((len -= copy) == 0) return 0; offset += copy; + from_offset += copy; } start = end; } diff --git a/net/core/iovec.c b/net/core/iovec.c index a215545c0a3..40a76ce19d9 100644 --- a/net/core/iovec.c +++ b/net/core/iovec.c @@ -147,10 +147,11 @@ int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len) } /* - * For use with ip_build_xmit + * Copy iovec from kernel. Returns -EFAULT on error. */ -int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset, - int len) + +int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov, + int offset, int len) { /* Skip over the finished iovecs */ while (offset >= iov->iov_len) { -- 2.41.0