Merge tag 'ASB-2018-07-05_4.4-o-release' into android-mediatek-mooneye-4.4android-wear-8.0.0_r0.58android-mediatek-mooneye-4.4-oreo-wear-dr

https://source.android.com/security/bulletin/2018-07-01
CVE-2018-9422
CVE-2018-9417
CVE-2018-6927
CVE-2018-9416
CVE-2018-9415
CVE-2018-9415
CVE-2018-7995
CVE-2018-1065
CVE-2017-18218
CVE-2017-1000112

Not included:
CVE-2018-5703 : Skipped due to fix rejected upstream

Change-Id: I8c23dd68a58e52fb772b98a77e09d419413d1cf5
Signed-off-by: Ben Fennema <fennema@google.com>

8 files changed, 128 insertions, 29 deletions

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 42086ad535c5..35603b7f0e90 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -68,11 +68,15 @@ static ssize_t driver_override_show(struct device *_dev,
 				    struct device_attribute *attr, char *buf)
 {
 	struct amba_device *dev = to_amba_device(_dev);
+	ssize_t len;
 
 	if (!dev->driver_override)
 		return 0;
 
-	return sprintf(buf, "%s\n", dev->driver_override);
+	device_lock(_dev);
+	len = sprintf(buf, "%s\n", dev->driver_override);
+	device_unlock(_dev);
+	return len;
 }
 
 static ssize_t driver_override_store(struct device *_dev,
@@ -80,7 +84,7 @@ static ssize_t driver_override_store(struct device *_dev,
 				     const char *buf, size_t count)
 {
 	struct amba_device *dev = to_amba_device(_dev);
-	char *driver_override, *old = dev->driver_override, *cp;
+	char *driver_override, *old, *cp;
 
 	/* We need to keep extra room for a newline */
 	if (count >= (PAGE_SIZE - 1))
@@ -94,12 +98,15 @@ static ssize_t driver_override_store(struct device *_dev,
 	if (cp)
 		*cp = '\0';
 
+	device_lock(_dev);
+	old = dev->driver_override;
 	if (strlen(driver_override)) {
 		dev->driver_override = driver_override;
 	} else {
 	       kfree(driver_override);
 	       dev->driver_override = NULL;
 	}
+	device_unlock(_dev);
 
 	kfree(old);
 
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index ee579ba2b59e..a5dae5bb62ab 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -223,6 +223,13 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 	/* pick the first one */
 	list = list_first_entry(&hidg->completed_out_req,
 				struct f_hidg_req_list, list);
+
+	/*
+	 * Remove this from list to protect it from beign free()
+	 * while host disables our function
+	 */
+	list_del(&list->list);
+
 	req = list->req;
 	count = min_t(unsigned int, count, req->actual - list->pos);
 	spin_unlock_irqrestore(&hidg->spinlock, flags);
@@ -238,15 +245,20 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 	 * call, taking into account its current read position.
 	 */
 	if (list->pos == req->actual) {
-		spin_lock_irqsave(&hidg->spinlock, flags);
-		list_del(&list->list);
 		kfree(list);
-		spin_unlock_irqrestore(&hidg->spinlock, flags);
 
 		req->length = hidg->report_length;
 		ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);
-		if (ret < 0)
+		if (ret < 0) {
+			free_ep_req(hidg->out_ep, req);
 			return ret;
+		}
+	} else {
+		spin_lock_irqsave(&hidg->spinlock, flags);
+		list_add(&list->list, &hidg->completed_out_req);
+		spin_unlock_irqrestore(&hidg->spinlock, flags);
+
+		wake_up(&hidg->read_queue);
 	}
 
 	return count;
@@ -490,14 +502,18 @@ static void hidg_disable(struct usb_function *f)
 {
 	struct f_hidg *hidg = func_to_hidg(f);
 	struct f_hidg_req_list *list, *next;
+	unsigned long flags;
 
 	usb_ep_disable(hidg->in_ep);
 	usb_ep_disable(hidg->out_ep);
 
+	spin_lock_irqsave(&hidg->spinlock, flags);
 	list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
+		free_ep_req(hidg->out_ep, list->req);
 		list_del(&list->list);
 		kfree(list);
 	}
+	spin_unlock_irqrestore(&hidg->spinlock, flags);
 }
 
 static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 315c2690afe1..514912a694a4 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -201,12 +201,6 @@ static inline struct usb_request *midi_alloc_ep_req(struct usb_ep *ep,
 	return alloc_ep_req(ep, length, length);
 }
 
-static void free_ep_req(struct usb_ep *ep, struct usb_request *req)
-{
-	kfree(req->buf);
-	usb_ep_free_request(ep, req);
-}
-
 static const uint8_t f_midi_cin_length[] = {
 	0, 0, 2, 3, 3, 1, 2, 3, 3, 3, 3, 3, 2, 2, 3, 1
 };
diff --git a/drivers/usb/gadget/function/f_sourcesink.c b/drivers/usb/gadget/function/f_sourcesink.c
index 9f3ced62d916..67b243989938 100644
--- a/drivers/usb/gadget/function/f_sourcesink.c
+++ b/drivers/usb/gadget/function/f_sourcesink.c
@@ -303,12 +303,6 @@ static inline struct usb_request *ss_alloc_ep_req(struct usb_ep *ep, int len)
 	return alloc_ep_req(ep, len, ss->buflen);
 }
 
-void free_ep_req(struct usb_ep *ep, struct usb_request *req)
-{
-	kfree(req->buf);
-	usb_ep_free_request(ep, req);
-}
-
 static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
 {
 	int			value;
diff --git a/drivers/usb/gadget/function/g_zero.h b/drivers/usb/gadget/function/g_zero.h
index 15f180904f8a..5ed90b437f18 100644
--- a/drivers/usb/gadget/function/g_zero.h
+++ b/drivers/usb/gadget/function/g_zero.h
@@ -59,7 +59,6 @@ void lb_modexit(void);
 int lb_modinit(void);
 
 /* common utilities */
-void free_ep_req(struct usb_ep *ep, struct usb_request *req);
 void disable_endpoints(struct usb_composite_dev *cdev,
 		struct usb_ep *in, struct usb_ep *out,
 		struct usb_ep *iso_in, struct usb_ep *iso_out);
diff --git a/drivers/usb/gadget/u_f.c b/drivers/usb/gadget/u_f.c
index c6276f0268ae..4bc7eea8bfc8 100644
--- a/drivers/usb/gadget/u_f.c
+++ b/drivers/usb/gadget/u_f.c
@@ -11,7 +11,6 @@
  * published by the Free Software Foundation.
  */
 
-#include <linux/usb/gadget.h>
 #include "u_f.h"
 
 struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len)
diff --git a/drivers/usb/gadget/u_f.h b/drivers/usb/gadget/u_f.h
index 1d5f0eb68552..4247cc098a89 100644
--- a/drivers/usb/gadget/u_f.h
+++ b/drivers/usb/gadget/u_f.h
@@ -16,6 +16,8 @@
 #ifndef __U_F_H__
 #define __U_F_H__
 
+#include <linux/usb/gadget.h>
+
 /* Variable Length Array Macros **********************************************/
 #define vla_group(groupname) size_t groupname##__next = 0
 #define vla_group_size(groupname) groupname##__next
@@ -45,8 +47,12 @@
 struct usb_ep;
 struct usb_request;
 
+/* Requests allocated via alloc_ep_req() must be freed by free_ep_req(). */
 struct usb_request *alloc_ep_req(struct usb_ep *ep, int len, int default_len);
+static inline void free_ep_req(struct usb_ep *ep, struct usb_request *req)
+{
+	kfree(req->buf);
+	usb_ep_free_request(ep, req);
+}
 
 #endif /* __U_F_H__ */
-
-
diff --git a/kernel/futex.c b/kernel/futex.c
index 1fce19fc824c..a12aa6785361 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -470,6 +470,7 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
 	unsigned long address = (unsigned long)uaddr;
 	struct mm_struct *mm = current->mm;
 	struct page *page, *page_head;
+	struct address_space *mapping;
 	int err, ro = 0;
 
 	/*
@@ -555,7 +556,19 @@ again:
 	}
 #endif
 
-	lock_page(page_head);
+	/*
+	 * The treatment of mapping from this point on is critical. The page
+	 * lock protects many things but in this context the page lock
+	 * stabilizes mapping, prevents inode freeing in the shared
+	 * file-backed region case and guards against movement to swap cache.
+	 *
+	 * Strictly speaking the page lock is not needed in all cases being
+	 * considered here and page lock forces unnecessarily serialization
+	 * From this point on, mapping will be re-verified if necessary and
+	 * page lock will be acquired only if it is unavoidable
+	 */
+
+	mapping = READ_ONCE(page_head->mapping);
 
 	/*
 	 * If page_head->mapping is NULL, then it cannot be a PageAnon
@@ -572,18 +585,31 @@ again:
 	 * shmem_writepage move it from filecache to swapcache beneath us:
 	 * an unlikely race, but we do need to retry for page_head->mapping.
 	 */
-	if (!page_head->mapping) {
-		int shmem_swizzled = PageSwapCache(page_head);
+	if (unlikely(!mapping)) {
+		int shmem_swizzled;
+
+		/*
+		 * Page lock is required to identify which special case above
+		 * applies. If this is really a shmem page then the page lock
+		 * will prevent unexpected transitions.
+		 */
+		lock_page(page);
+		shmem_swizzled = PageSwapCache(page) || page->mapping;
 		unlock_page(page_head);
 		put_page(page_head);
+
 		if (shmem_swizzled)
 			goto again;
+
 		return -EFAULT;
 	}
 
 	/*
 	 * Private mappings are handled in a simple way.
 	 *
+	 * If the futex key is stored on an anonymous page, then the associated
+	 * object is the mm which is implicitly pinned by the calling process.
+	 *
 	 * NOTE: When userspace waits on a MAP_SHARED mapping, even if
 	 * it's a read-only handle, it's expected that futexes attach to
 	 * the object not the particular process.
@@ -601,16 +627,74 @@ again:
 		key->both.offset |= FUT_OFF_MMSHARED; /* ref taken on mm */
 		key->private.mm = mm;
 		key->private.address = address;
+
+		get_futex_key_refs(key); /* implies smp_mb(); (B) */
+
 	} else {
+		struct inode *inode;
+
+		/*
+		 * The associated futex object in this case is the inode and
+		 * the page->mapping must be traversed. Ordinarily this should
+		 * be stabilised under page lock but it's not strictly
+		 * necessary in this case as we just want to pin the inode, not
+		 * update the radix tree or anything like that.
+		 *
+		 * The RCU read lock is taken as the inode is finally freed
+		 * under RCU. If the mapping still matches expectations then the
+		 * mapping->host can be safely accessed as being a valid inode.
+		 */
+		rcu_read_lock();
+
+		if (READ_ONCE(page_head->mapping) != mapping) {
+			rcu_read_unlock();
+			put_page(page_head);
+
+			goto again;
+		}
+
+		inode = READ_ONCE(mapping->host);
+		if (!inode) {
+			rcu_read_unlock();
+			put_page(page_head);
+
+			goto again;
+		}
+
+		/*
+		 * Take a reference unless it is about to be freed. Previously
+		 * this reference was taken by ihold under the page lock
+		 * pinning the inode in place so i_lock was unnecessary. The
+		 * only way for this check to fail is if the inode was
+		 * truncated in parallel so warn for now if this happens.
+		 *
+		 * We are not calling into get_futex_key_refs() in file-backed
+		 * cases, therefore a successful atomic_inc return below will
+		 * guarantee that get_futex_key() will still imply smp_mb(); (B).
+		 */
+		if (WARN_ON_ONCE(!atomic_inc_not_zero(&inode->i_count))) {
+			rcu_read_unlock();
+			put_page(page_head);
+
+			goto again;
+		}
+
+		/* Should be impossible but lets be paranoid for now */
+		if (WARN_ON_ONCE(inode->i_mapping != mapping)) {
+			err = -EFAULT;
+			rcu_read_unlock();
+			iput(inode);
+
+			goto out;
+		}
+
 		key->both.offset |= FUT_OFF_INODE; /* inode-based key */
-		key->shared.inode = page_head->mapping->host;
+		key->shared.inode = inode;
 		key->shared.pgoff = basepage_index(page);
+		rcu_read_unlock();
 	}
 
-	get_futex_key_refs(key); /* implies MB (B) */
-
 out:
-	unlock_page(page_head);
 	put_page(page_head);
 	return err;
 }