Commit dc109d57 authored Jul 23, 2017 by Ernesto A. Fernández Committed by Jaegeuk Kim Aug 08, 2017

f2fs: preserve i_mode if __f2fs_set_acl() fails



When changing a file's acl mask, __f2fs_set_acl() will first set the
group bits of i_mode to the value of the mask, and only then set the
actual extended attribute representing the new acl.

If the second part fails (due to lack of space, for example) and the
file had no acl attribute to begin with, the system will from now on
assume that the mask permission bits are actual group permission bits,
potentially granting access to the wrong users.

Prevent this by only changing the inode mode after the acl has been set.

Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

parent b673d377

fs/f2fs/acl.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -207,15 +207,16 @@ static int __f2fs_set_acl(struct inode *inode, int type,
		void *value = NULL;
		size_t size = 0;
		int error;
		umode_t mode = inode->i_mode;

		switch (type) {
		case ACL_TYPE_ACCESS:
		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
		if (acl && !ipage) {
		error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
		error = posix_acl_update_mode(inode, &mode, &acl);
		if (error)
		return error;
		set_acl_inode(inode, inode->i_mode);
		set_acl_inode(inode, mode);
		}
		break;