fs: out of bounds on stack in iov_iter_advance

On Wed, Nov 11, 2015 at 10:19:48AM +0000, Al Viro wrote:

> I'll cook the minimal fixup for API change after I get some sleep and
> send it your way, unless somebody gets there first...

This should do it - switches ->ioctl() to pvfs2_inode_[gs]etxattr() and
converts xattr_handler ->[gs]et() to new API.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Mike Marshall <hubcap@omnibond.com>

fs/orangefs/file.c

@@ -506,11 +506,10 @@ static long pvfs2_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	 */
 	if (cmd == FS_IOC_GETFLAGS) {
 		val = 0;
-		ret = pvfs2_xattr_get_default(file->f_path.dentry,
-					      "user.pvfs2.meta_hint",
-					      &val,
-					      sizeof(val),
-					      0);
+		ret = pvfs2_inode_getxattr(file_inode(file),
+					   PVFS2_XATTR_NAME_DEFAULT_PREFIX,
+					   "user.pvfs2.meta_hint",
+					   &val, sizeof(val));
 		if (ret < 0 && ret != -ENODATA)
 			return ret;
 		else if (ret == -ENODATA)
@@ -540,12 +539,10 @@ static long pvfs2_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		gossip_debug(GOSSIP_FILE_DEBUG,
 			     "pvfs2_ioctl: FS_IOC_SETFLAGS: %llu\n",
 			     (unsigned long long)val);
-		ret = pvfs2_xattr_set_default(file->f_path.dentry,
-					      "user.pvfs2.meta_hint",
-					      &val,
-					      sizeof(val),
-					      0,
-					      0);
+		ret = pvfs2_inode_setxattr(file_inode(file),
+					   PVFS2_XATTR_NAME_DEFAULT_PREFIX,
+					   "user.pvfs2.meta_hint",
+					   &val, sizeof(val), 0);
 	}
 
 	return ret;

fs/orangefs/pvfs2-kernel.h

@@ -234,19 +234,6 @@ extern const struct xattr_handler *pvfs2_xattr_handlers[];
 extern struct posix_acl *pvfs2_get_acl(struct inode *inode, int type);
 extern int pvfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type);
 
-int pvfs2_xattr_set_default(struct dentry *dentry,
-			    const char *name,
-			    const void *buffer,
-			    size_t size,
-			    int flags,
-			    int handler_flags);
-
-int pvfs2_xattr_get_default(struct dentry *dentry,
-			    const char *name,
-			    void *buffer,
-			    size_t size,
-			    int handler_flags);
-
 /*
  * Redefine xtvec structure so that we could move helper functions out of
  * the define

fs/orangefs/xattr.c

@@ -447,12 +447,12 @@ out_unlock:
 	return ret;
 }
 
-int pvfs2_xattr_set_default(struct dentry *dentry,
-			    const char *name,
-			    const void *buffer,
-			    size_t size,
-			    int flags,
-			    int handler_flags)
+static int pvfs2_xattr_set_default(const struct xattr_handler *handler,
+				   struct dentry *dentry,
+				   const char *name,
+				   const void *buffer,
+				   size_t size,
+				   int flags)
 {
 	return pvfs2_inode_setxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_DEFAULT_PREFIX,
@@ -462,11 +462,11 @@ int pvfs2_xattr_set_default(struct dentry *dentry,
 				    flags);
 }
 
-int pvfs2_xattr_get_default(struct dentry *dentry,
-			    const char *name,
-			    void *buffer,
-			    size_t size,
-			    int handler_flags)
+static int pvfs2_xattr_get_default(const struct xattr_handler *handler,
+				   struct dentry *dentry,
+				   const char *name,
+				   void *buffer,
+				   size_t size)
 {
 	return pvfs2_inode_getxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_DEFAULT_PREFIX,
@@ -476,12 +476,12 @@ int pvfs2_xattr_get_default(struct dentry *dentry,
 
 }
 
-static int pvfs2_xattr_set_trusted(struct dentry *dentry,
-			    const char *name,
-			    const void *buffer,
-			    size_t size,
-			    int flags,
-			    int handler_flags)
+static int pvfs2_xattr_set_trusted(const struct xattr_handler *handler,
+				   struct dentry *dentry,
+				   const char *name,
+				   const void *buffer,
+				   size_t size,
+				   int flags)
 {
 	return pvfs2_inode_setxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_TRUSTED_PREFIX,
@@ -491,11 +491,11 @@ static int pvfs2_xattr_set_trusted(struct dentry *dentry,
 				    flags);
 }
 
-static int pvfs2_xattr_get_trusted(struct dentry *dentry,
-			    const char *name,
-			    void *buffer,
-			    size_t size,
-			    int handler_flags)
+static int pvfs2_xattr_get_trusted(const struct xattr_handler *handler,
+				   struct dentry *dentry,
+				   const char *name,
+				   void *buffer,
+				   size_t size)
 {
 	return pvfs2_inode_getxattr(dentry->d_inode,
 				    PVFS2_XATTR_NAME_TRUSTED_PREFIX,