[arch-commits] Commit in linux/trunk (2 files)

Andreas Radke andyrtr at archlinux.org
Mon Mar 13 16:54:13 UTC 2017


    Date: Monday, March 13, 2017 @ 16:54:12
  Author: andyrtr
Revision: 290792

upgpkg: linux 4.10.2-1

upstream update 4.10.2;  apply fix for CVE-2017-2636

Added:
  linux/trunk/0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch
Modified:
  linux/trunk/PKGBUILD

---------------------------------------------------+
 0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch |  311 ++++++++++++++++++++
 PKGBUILD                                          |   12 
 2 files changed, 319 insertions(+), 4 deletions(-)

Added: 0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch
===================================================================
--- 0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch	                        (rev 0)
+++ 0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch	2017-03-13 16:54:12 UTC (rev 290792)
@@ -0,0 +1,311 @@
+>From 1dea7a8061ad9212f4464464a80d0dcd477eceab Mon Sep 17 00:00:00 2001
+From: Alexander Popov <alex.popov () linux com>
+Date: Tue, 28 Feb 2017 19:28:54 +0300
+Subject: [PATCH 1/1] tty: n_hdlc: get rid of racy n_hdlc.tbuf
+
+Currently N_HDLC line discipline uses a self-made singly linked list for
+data buffers and has n_hdlc.tbuf pointer for buffer retransmitting after
+an error.
+
+The commit be10eb7589337e5defbe214dae038a53dd21add8
+("tty: n_hdlc add buffer flushing") introduced racy access to n_hdlc.tbuf.
+After tx error concurrent flush_tx_queue() and n_hdlc_send_frames() can put
+one data buffer to tx_free_buf_list twice. That causes double free in
+n_hdlc_release().
+
+Let's use standard kernel linked list and get rid of n_hdlc.tbuf:
+in case of tx error put current data buffer after the head of tx_buf_list.
+
+Signed-off-by: Alexander Popov <alex.popov () linux com>
+---
+ drivers/tty/n_hdlc.c | 132 +++++++++++++++++++++++++++------------------------
+ 1 file changed, 69 insertions(+), 63 deletions(-)
+
+diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c
+index eb27883..728c824 100644
+--- a/drivers/tty/n_hdlc.c
++++ b/drivers/tty/n_hdlc.c
+@@ -114,7 +114,7 @@
+ #define DEFAULT_TX_BUF_COUNT 3
+ 
+ struct n_hdlc_buf {
+-	struct n_hdlc_buf *link;
++	struct list_head  list_item;
+ 	int		  count;
+ 	char		  buf[1];
+ };
+@@ -122,8 +122,7 @@ struct n_hdlc_buf {
+ #define	N_HDLC_BUF_SIZE	(sizeof(struct n_hdlc_buf) + maxframe)
+ 
+ struct n_hdlc_buf_list {
+-	struct n_hdlc_buf *head;
+-	struct n_hdlc_buf *tail;
++	struct list_head  list;
+ 	int		  count;
+ 	spinlock_t	  spinlock;
+ };
+@@ -136,7 +135,6 @@ struct n_hdlc_buf_list {
+  * @backup_tty - TTY to use if tty gets closed
+  * @tbusy - reentrancy flag for tx wakeup code
+  * @woke_up - FIXME: describe this field
+- * @tbuf - currently transmitting tx buffer
+  * @tx_buf_list - list of pending transmit frame buffers
+  * @rx_buf_list - list of received frame buffers
+  * @tx_free_buf_list - list unused transmit frame buffers
+@@ -149,7 +147,6 @@ struct n_hdlc {
+ 	struct tty_struct	*backup_tty;
+ 	int			tbusy;
+ 	int			woke_up;
+-	struct n_hdlc_buf	*tbuf;
+ 	struct n_hdlc_buf_list	tx_buf_list;
+ 	struct n_hdlc_buf_list	rx_buf_list;
+ 	struct n_hdlc_buf_list	tx_free_buf_list;
+@@ -159,6 +156,8 @@ struct n_hdlc {
+ /*
+  * HDLC buffer list manipulation functions
+  */
++static void n_hdlc_buf_return(struct n_hdlc_buf_list *buf_list,
++						struct n_hdlc_buf *buf);
+ static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
+ 			   struct n_hdlc_buf *buf);
+ static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *list);
+@@ -208,16 +207,9 @@ static void flush_tx_queue(struct tty_struct *tty)
+ {
+ 	struct n_hdlc *n_hdlc = tty2n_hdlc(tty);
+ 	struct n_hdlc_buf *buf;
+-	unsigned long flags;
+ 
+ 	while ((buf = n_hdlc_buf_get(&n_hdlc->tx_buf_list)))
+ 		n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, buf);
+- 	spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock, flags);
+-	if (n_hdlc->tbuf) {
+-		n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, n_hdlc->tbuf);
+-		n_hdlc->tbuf = NULL;
+-	}
+-	spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
+ }
+ 
+ static struct tty_ldisc_ops n_hdlc_ldisc = {
+@@ -283,7 +275,6 @@ static void n_hdlc_release(struct n_hdlc *n_hdlc)
+ 		} else
+ 			break;
+ 	}
+-	kfree(n_hdlc->tbuf);
+ 	kfree(n_hdlc);
+ 	
+ }	/* end of n_hdlc_release() */
+@@ -402,13 +393,7 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
+ 	n_hdlc->woke_up = 0;
+ 	spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock, flags);
+ 
+-	/* get current transmit buffer or get new transmit */
+-	/* buffer from list of pending transmit buffers */
+-		
+-	tbuf = n_hdlc->tbuf;
+-	if (!tbuf)
+-		tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
+-		
++	tbuf = n_hdlc_buf_get(&n_hdlc->tx_buf_list);
+ 	while (tbuf) {
+ 		if (debuglevel >= DEBUG_LEVEL_INFO)	
+ 			printk("%s(%d)sending frame %p, count=%d\n",
+@@ -420,7 +405,7 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
+ 
+ 		/* rollback was possible and has been done */
+ 		if (actual == -ERESTARTSYS) {
+-			n_hdlc->tbuf = tbuf;
++			n_hdlc_buf_return(&n_hdlc->tx_buf_list, tbuf);
+ 			break;
+ 		}
+ 		/* if transmit error, throw frame away by */
+@@ -435,10 +420,7 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
+ 					
+ 			/* free current transmit buffer */
+ 			n_hdlc_buf_put(&n_hdlc->tx_free_buf_list, tbuf);
+-			
+-			/* this tx buffer is done */
+-			n_hdlc->tbuf = NULL;
+-			
++
+ 			/* wait up sleeping writers */
+ 			wake_up_interruptible(&tty->write_wait);
+ 	
+@@ -448,10 +430,12 @@ static void n_hdlc_send_frames(struct n_hdlc *n_hdlc, struct tty_struct *tty)
+ 			if (debuglevel >= DEBUG_LEVEL_INFO)	
+ 				printk("%s(%d)frame %p pending\n",
+ 					__FILE__,__LINE__,tbuf);
+-					
+-			/* buffer not accepted by driver */
+-			/* set this buffer as pending buffer */
+-			n_hdlc->tbuf = tbuf;
++
++			/*
++			 * the buffer was not accepted by driver,
++			 * return it back into tx queue
++			 */
++			n_hdlc_buf_return(&n_hdlc->tx_buf_list, tbuf);
+ 			break;
+ 		}
+ 	}
+@@ -749,7 +733,8 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
+ 	int error = 0;
+ 	int count;
+ 	unsigned long flags;
+-	
++	struct n_hdlc_buf *buf = NULL;
++
+ 	if (debuglevel >= DEBUG_LEVEL_INFO)	
+ 		printk("%s(%d)n_hdlc_tty_ioctl() called %d\n",
+ 			__FILE__,__LINE__,cmd);
+@@ -763,8 +748,10 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
+ 		/* report count of read data available */
+ 		/* in next available frame (if any) */
+ 		spin_lock_irqsave(&n_hdlc->rx_buf_list.spinlock,flags);
+-		if (n_hdlc->rx_buf_list.head)
+-			count = n_hdlc->rx_buf_list.head->count;
++		buf = list_first_entry_or_null(&n_hdlc->rx_buf_list.list,
++						struct n_hdlc_buf, list_item);
++		if (buf)
++			count = buf->count;
+ 		else
+ 			count = 0;
+ 		spin_unlock_irqrestore(&n_hdlc->rx_buf_list.spinlock,flags);
+@@ -776,8 +763,10 @@ static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
+ 		count = tty_chars_in_buffer(tty);
+ 		/* add size of next output frame in queue */
+ 		spin_lock_irqsave(&n_hdlc->tx_buf_list.spinlock,flags);
+-		if (n_hdlc->tx_buf_list.head)
+-			count += n_hdlc->tx_buf_list.head->count;
++		buf = list_first_entry_or_null(&n_hdlc->tx_buf_list.list,
++						struct n_hdlc_buf, list_item);
++		if (buf)
++			count += buf->count;
+ 		spin_unlock_irqrestore(&n_hdlc->tx_buf_list.spinlock,flags);
+ 		error = put_user(count, (int __user *)arg);
+ 		break;
+@@ -825,14 +814,14 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
+ 		poll_wait(filp, &tty->write_wait, wait);
+ 
+ 		/* set bits for operations that won't block */
+-		if (n_hdlc->rx_buf_list.head)
++		if (!list_empty(&n_hdlc->rx_buf_list.list))
+ 			mask |= POLLIN | POLLRDNORM;	/* readable */
+ 		if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
+ 			mask |= POLLHUP;
+ 		if (tty_hung_up_p(filp))
+ 			mask |= POLLHUP;
+ 		if (!tty_is_writelocked(tty) &&
+-				n_hdlc->tx_free_buf_list.head)
++				!list_empty(&n_hdlc->tx_free_buf_list.list))
+ 			mask |= POLLOUT | POLLWRNORM;	/* writable */
+ 	}
+ 	return mask;
+@@ -856,7 +845,12 @@ static struct n_hdlc *n_hdlc_alloc(void)
+ 	spin_lock_init(&n_hdlc->tx_free_buf_list.spinlock);
+ 	spin_lock_init(&n_hdlc->rx_buf_list.spinlock);
+ 	spin_lock_init(&n_hdlc->tx_buf_list.spinlock);
+-	
++
++	INIT_LIST_HEAD(&n_hdlc->rx_free_buf_list.list);
++	INIT_LIST_HEAD(&n_hdlc->tx_free_buf_list.list);
++	INIT_LIST_HEAD(&n_hdlc->rx_buf_list.list);
++	INIT_LIST_HEAD(&n_hdlc->tx_buf_list.list);
++
+ 	/* allocate free rx buffer list */
+ 	for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) {
+ 		buf = kmalloc(N_HDLC_BUF_SIZE, GFP_KERNEL);
+@@ -884,53 +878,65 @@ static struct n_hdlc *n_hdlc_alloc(void)
+ }	/* end of n_hdlc_alloc() */
+ 
+ /**
++ * n_hdlc_buf_return - put the HDLC buffer after the head of the specified list
++ * @buf_list - pointer to the buffer list
++ * @buf - pointer to the buffer
++ */
++static void n_hdlc_buf_return(struct n_hdlc_buf_list *buf_list,
++						struct n_hdlc_buf *buf)
++{
++	unsigned long flags;
++
++	spin_lock_irqsave(&buf_list->spinlock, flags);
++
++	list_add(&buf->list_item, &buf_list->list);
++	buf_list->count++;
++
++	spin_unlock_irqrestore(&buf_list->spinlock, flags);
++}
++
++/**
+  * n_hdlc_buf_put - add specified HDLC buffer to tail of specified list
+- * @list - pointer to buffer list
++ * @buf_list - pointer to buffer list
+  * @buf	- pointer to buffer
+  */
+-static void n_hdlc_buf_put(struct n_hdlc_buf_list *list,
++static void n_hdlc_buf_put(struct n_hdlc_buf_list *buf_list,
+ 			   struct n_hdlc_buf *buf)
+ {
+ 	unsigned long flags;
+-	spin_lock_irqsave(&list->spinlock,flags);
+-	
+-	buf->link=NULL;
+-	if (list->tail)
+-		list->tail->link = buf;
+-	else
+-		list->head = buf;
+-	list->tail = buf;
+-	(list->count)++;
+-	
+-	spin_unlock_irqrestore(&list->spinlock,flags);
+-	
++
++	spin_lock_irqsave(&buf_list->spinlock, flags);
++
++	list_add_tail(&buf->list_item, &buf_list->list);
++	buf_list->count++;
++
++	spin_unlock_irqrestore(&buf_list->spinlock, flags);
+ }	/* end of n_hdlc_buf_put() */
+ 
+ /**
+  * n_hdlc_buf_get - remove and return an HDLC buffer from list
+- * @list - pointer to HDLC buffer list
++ * @buf_list - pointer to HDLC buffer list
+  * 
+  * Remove and return an HDLC buffer from the head of the specified HDLC buffer
+  * list.
+  * Returns a pointer to HDLC buffer if available, otherwise %NULL.
+  */
+-static struct n_hdlc_buf* n_hdlc_buf_get(struct n_hdlc_buf_list *list)
++static struct n_hdlc_buf *n_hdlc_buf_get(struct n_hdlc_buf_list *buf_list)
+ {
+ 	unsigned long flags;
+ 	struct n_hdlc_buf *buf;
+-	spin_lock_irqsave(&list->spinlock,flags);
+-	
+-	buf = list->head;
++
++	spin_lock_irqsave(&buf_list->spinlock, flags);
++
++	buf = list_first_entry_or_null(&buf_list->list,
++						struct n_hdlc_buf, list_item);
+ 	if (buf) {
+-		list->head = buf->link;
+-		(list->count)--;
++		list_del(&buf->list_item);
++		buf_list->count--;
+ 	}
+-	if (!list->head)
+-		list->tail = NULL;
+-	
+-	spin_unlock_irqrestore(&list->spinlock,flags);
++
++	spin_unlock_irqrestore(&buf_list->spinlock, flags);
+ 	return buf;
+-	
+ }	/* end of n_hdlc_buf_get() */
+ 
+ static char hdlc_banner[] __initdata =
+-- 
+2.7.4
+

Modified: PKGBUILD
===================================================================
--- PKGBUILD	2017-03-13 15:45:50 UTC (rev 290791)
+++ PKGBUILD	2017-03-13 16:54:12 UTC (rev 290792)
@@ -5,7 +5,7 @@
 pkgbase=linux               # Build stock -ARCH kernel
 #pkgbase=linux-custom       # Build kernel with a different name
 _srcname=linux-4.10
-pkgver=4.10.1
+pkgver=4.10.2
 pkgrel=1
 arch=('i686' 'x86_64')
 url="https://www.kernel.org/"
@@ -22,16 +22,17 @@
         '99-linux.hook'
         # standard config files for mkinitcpio ramdisk
         'linux.preset'
-        )
+        0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch)
 
 sha256sums=('3c95d9f049bd085e5c346d2c77f063b8425f191460fcd3ae9fe7e94e0477dc4b'
             'SKIP'
-            'da560125aa350f76f0e4a5b9373a0d0a1c27ccefe3b7bd9231724f3a3c4ebb9e'
+            '3e2c2ba9dd2c421ea4f7e10150cc5f5fa5fdbaffef5377988fabb7d6f7d65bab'
             'SKIP'
             '386051f19482672c871e7865fc62f5e2c8010d857729134ba13044734962e42c'
             '12a87284e2935cd17e2846a207cc76f1728531416523735d66ef8a0ae690884c'
             '834bd254b56ab71d73f59b3221f056c72f559553c04718e350ab2a3e2991afe0'
-            'ad6344badc91ad0630caacde83f7f9b97276f80d26a20619a87952be65492c65')
+            'ad6344badc91ad0630caacde83f7f9b97276f80d26a20619a87952be65492c65'
+            'd0b412416963cefbb9baa06ef055e2b9485e2b9f948da14dfe50ee863577405c')
 validpgpkeys=(
               'ABAF11C65A2970B130ABE3C479BE3E4300411886' # Linus Torvalds
               '647F28654894E3BD457199BE38DBBDC86092693E' # Greg Kroah-Hartman
@@ -48,6 +49,9 @@
   # add latest fixes from stable queue, if needed
   # http://git.kernel.org/?p=linux/kernel/git/stable/stable-queue.git
 
+  # patch for CVE-2017-2636)
+  patch -p1 -i "${srcdir}/0001-tty-n_hdlc-get-rid-of-racy-n_hdlc_tbuf.patch"
+
   cat "${srcdir}/config.${CARCH}" > ./.config
 
   if [ "${_kernelname}" != "" ]; then


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