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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	Daniel Borkmann <dborkman@redhat.com>,
	Thomas Graf <tgraf@suug.ch>
Subject: [PATCH 3.10 01/50] netlink: Always copy on mmap TX.
Date: Sun, 25 Jan 2015 10:06:51 -0800	[thread overview]
Message-ID: <20150125180702.677130456@linuxfoundation.org> (raw)
In-Reply-To: <20150125180702.521559311@linuxfoundation.org>

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Miller <davem@davemloft.net>

[ Upstream commit 4682a0358639b29cf69437ed909c6221f8c89847 ]

Checking the file f_count and the nlk->mapped count is not completely
sufficient to prevent the mmap'd area contents from changing from
under us during netlink mmap sendmsg() operations.

Be careful to sample the header's length field only once, because this
could change from under us as well.

Fixes: 5fd96123ee19 ("netlink: implement memory mapped sendmsg()")
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netlink/af_netlink.c |   52 ++++++++++++++---------------------------------
 1 file changed, 16 insertions(+), 36 deletions(-)

--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -374,14 +374,14 @@ out:
 	return err;
 }
 
-static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr)
+static void netlink_frame_flush_dcache(const struct nl_mmap_hdr *hdr, unsigned int nm_len)
 {
 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE == 1
 	struct page *p_start, *p_end;
 
 	/* First page is flushed through netlink_{get,set}_status */
 	p_start = pgvec_to_page(hdr + PAGE_SIZE);
-	p_end   = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + hdr->nm_len - 1);
+	p_end   = pgvec_to_page((void *)hdr + NL_MMAP_HDRLEN + nm_len - 1);
 	while (p_start <= p_end) {
 		flush_dcache_page(p_start);
 		p_start++;
@@ -563,24 +563,16 @@ static int netlink_mmap_sendmsg(struct s
 	struct nl_mmap_hdr *hdr;
 	struct sk_buff *skb;
 	unsigned int maxlen;
-	bool excl = true;
 	int err = 0, len = 0;
 
-	/* Netlink messages are validated by the receiver before processing.
-	 * In order to avoid userspace changing the contents of the message
-	 * after validation, the socket and the ring may only be used by a
-	 * single process, otherwise we fall back to copying.
-	 */
-	if (atomic_long_read(&sk->sk_socket->file->f_count) > 1 ||
-	    atomic_read(&nlk->mapped) > 1)
-		excl = false;
-
 	mutex_lock(&nlk->pg_vec_lock);
 
 	ring   = &nlk->tx_ring;
 	maxlen = ring->frame_size - NL_MMAP_HDRLEN;
 
 	do {
+		unsigned int nm_len;
+
 		hdr = netlink_current_frame(ring, NL_MMAP_STATUS_VALID);
 		if (hdr == NULL) {
 			if (!(msg->msg_flags & MSG_DONTWAIT) &&
@@ -588,35 +580,23 @@ static int netlink_mmap_sendmsg(struct s
 				schedule();
 			continue;
 		}
-		if (hdr->nm_len > maxlen) {
+
+		nm_len = ACCESS_ONCE(hdr->nm_len);
+		if (nm_len > maxlen) {
 			err = -EINVAL;
 			goto out;
 		}
 
-		netlink_frame_flush_dcache(hdr);
+		netlink_frame_flush_dcache(hdr, nm_len);
 
-		if (likely(dst_portid == 0 && dst_group == 0 && excl)) {
-			skb = alloc_skb_head(GFP_KERNEL);
-			if (skb == NULL) {
-				err = -ENOBUFS;
-				goto out;
-			}
-			sock_hold(sk);
-			netlink_ring_setup_skb(skb, sk, ring, hdr);
-			NETLINK_CB(skb).flags |= NETLINK_SKB_TX;
-			__skb_put(skb, hdr->nm_len);
-			netlink_set_status(hdr, NL_MMAP_STATUS_RESERVED);
-			atomic_inc(&ring->pending);
-		} else {
-			skb = alloc_skb(hdr->nm_len, GFP_KERNEL);
-			if (skb == NULL) {
-				err = -ENOBUFS;
-				goto out;
-			}
-			__skb_put(skb, hdr->nm_len);
-			memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, hdr->nm_len);
-			netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
+		skb = alloc_skb(nm_len, GFP_KERNEL);
+		if (skb == NULL) {
+			err = -ENOBUFS;
+			goto out;
 		}
+		__skb_put(skb, nm_len);
+		memcpy(skb->data, (void *)hdr + NL_MMAP_HDRLEN, nm_len);
+		netlink_set_status(hdr, NL_MMAP_STATUS_UNUSED);
 
 		netlink_increment_head(ring);
 
@@ -662,7 +642,7 @@ static void netlink_queue_mmaped_skb(str
 	hdr->nm_pid	= NETLINK_CB(skb).creds.pid;
 	hdr->nm_uid	= from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
 	hdr->nm_gid	= from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
-	netlink_frame_flush_dcache(hdr);
+	netlink_frame_flush_dcache(hdr, hdr->nm_len);
 	netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
 
 	NETLINK_CB(skb).flags |= NETLINK_SKB_DELIVERED;



  reply	other threads:[~2015-01-25 18:08 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-25 18:06 [PATCH 3.10 00/50] 3.10.66-stable review Greg Kroah-Hartman
2015-01-25 18:06 ` Greg Kroah-Hartman [this message]
2015-01-25 18:06 ` [PATCH 3.10 02/50] netlink: Dont reorder loads/stores before marking mmap netlink frame as available Greg Kroah-Hartman
2015-01-25 18:06 ` [PATCH 3.10 03/50] tg3: tg3_disable_ints using uninitialized mailbox value to disable interrupts Greg Kroah-Hartman
2015-01-25 18:06 ` [PATCH 3.10 04/50] tcp: Do not apply TSO segment limit to non-TSO packets Greg Kroah-Hartman
2015-01-25 18:06 ` [PATCH 3.10 05/50] alx: fix alx_poll() Greg Kroah-Hartman
2015-01-25 18:06 ` [PATCH 3.10 06/50] enic: fix rx skb checksum Greg Kroah-Hartman
2015-01-25 18:06 ` [PATCH 3.10 07/50] drm/vmwgfx: Fix fence event code Greg Kroah-Hartman
2015-01-25 18:06 ` [PATCH 3.10 09/50] drm/radeon: properly filter DP1.2 4k modes on non-DP1.2 hw Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 12/50] ARC: [nsimosci] move peripherals to match model to FPGA Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 13/50] cfg80211: Fix 160 MHz channels with 80+80 and 160 MHz drivers Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 14/50] hp_accel: Add support for HP ZBook 15 Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 15/50] iscsi-target: Fail connection on short sendmsg writes Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 16/50] storvsc: ring buffer failures may result in I/O freeze Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 17/50] video/logo: prevent use of logos after they have been freed Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 18/50] [media] smiapp-pll: Correct clock debug prints Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 20/50] [media] smiapp: Take mutex during PLL update in sensor initialisation Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 21/50] [media] uvcvideo: Fix destruction order in uvc_delete() Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 22/50] vfio-pci: Fix the check on pci device type in vfio_pci_probe() Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 23/50] ftrace/jprobes/x86: Fix conflict between jprobes and function graph tracing Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 24/50] NFSv4.1: Fix client id trunking on Linux Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 25/50] gpiolib: of: Correct error handling in of_get_named_gpiod_flags Greg Kroah-Hartman
2015-01-25 21:31   ` Guenter Roeck
2015-01-25 22:05     ` Greg Kroah-Hartman
2015-01-26  0:29       ` Guenter Roeck
2015-01-26 18:35         ` Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 26/50] OHCI: add a quirk for ULi M5237 blocking on reset Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 27/50] usb: dwc3: gadget: Fix TRB preparation during SG Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 28/50] usb: dwc3: gadget: Stop TRB preparation after limit is reached Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 29/50] USB: cp210x: fix ID for production CEL MeshConnect USB Stick Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 30/50] USB: cp210x: add IDs for CEL USB sticks and MeshWorks devices Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 31/50] USB: keyspan: fix null-deref at probe Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 32/50] can: kvaser_usb: Dont free packets when tight on URBs Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 33/50] can: kvaser_usb: Reset all URB tx contexts upon channel close Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 34/50] can: kvaser_usb: Dont send a RESET_CHIP for non-existing channels Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 36/50] Input: I8042 - add Acer Aspire 7738 to the nomux list Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 37/50] ARM: dts: imx25: Fix the SPI1 clocks Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 38/50] ARM: imx6q: drop unnecessary semicolon Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 39/50] ARM: clk-imx6q: fix video divider for rev T0 1.0 Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 40/50] ARM: omap5/dra7xx: Fix frequency typos Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 41/50] ARM: shmobile: sh73a0 legacy: Set .control_parent for all irqpin instances Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 42/50] decompress_bunzip2: off by one in get_next_block() Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 43/50] um: Skip futex_atomic_cmpxchg_inatomic() test Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 44/50] x86, um: actually mark system call tables readonly Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 45/50] LOCKD: Fix a race when initialising nlmsvc_timeout Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 46/50] mmc: sdhci: Fix sleep in atomic after inserting SD card Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 47/50] netfilter: ipset: small potential read beyond the end of buffer Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 48/50] fsnotify: next_i is freed during fsnotify_unmount_inodes Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 49/50] s390/3215: fix hanging console issue Greg Kroah-Hartman
2015-01-25 18:07 ` [PATCH 3.10 50/50] s390/3215: fix tty output containing tabs Greg Kroah-Hartman
2015-01-25 20:57 ` [PATCH 3.10 00/50] 3.10.66-stable review Guenter Roeck
2015-01-25 21:35 ` Guenter Roeck
2015-01-26 17:43 ` Shuah Khan

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