diff options
| -rw-r--r-- | fs/overlayfs/file.c | 79 |
1 files changed, 61 insertions, 18 deletions
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 7d2f01957e40..540a8b845145 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -11,6 +11,7 @@ #include <linux/mount.h> #include <linux/xattr.h> #include <linux/uio.h> +#include <linux/uaccess.h> #include "overlayfs.h" static char ovl_whatisit(struct inode *inode, struct inode *realinode) @@ -408,10 +409,68 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd, return ret; } -static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +static unsigned int ovl_get_inode_flags(struct inode *inode) +{ + unsigned int flags = READ_ONCE(inode->i_flags); + unsigned int ovl_iflags = 0; + + if (flags & S_SYNC) + ovl_iflags |= FS_SYNC_FL; + if (flags & S_APPEND) + ovl_iflags |= FS_APPEND_FL; + if (flags & S_IMMUTABLE) + ovl_iflags |= FS_IMMUTABLE_FL; + if (flags & S_NOATIME) + ovl_iflags |= FS_NOATIME_FL; + + return ovl_iflags; +} + +static long ovl_ioctl_set_flags(struct file *file, unsigned long arg) { long ret; struct inode *inode = file_inode(file); + unsigned int flags; + unsigned int old_flags; + + if (!inode_owner_or_capable(inode)) + return -EACCES; + + if (get_user(flags, (int __user *) arg)) + return -EFAULT; + + ret = mnt_want_write_file(file); + if (ret) + return ret; + + inode_lock(inode); + + /* Check the capability before cred override */ + ret = -EPERM; + old_flags = ovl_get_inode_flags(inode); + if (((flags ^ old_flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) && + !capable(CAP_LINUX_IMMUTABLE)) + goto unlock; + + ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY); + if (ret) + goto unlock; + + ret = ovl_real_ioctl(file, FS_IOC_SETFLAGS, arg); + + ovl_copyflags(ovl_inode_real(inode), inode); +unlock: + inode_unlock(inode); + + mnt_drop_write_file(file); + + return ret; + +} + +static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + long ret; switch (cmd) { case FS_IOC_GETFLAGS: @@ -419,23 +478,7 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg) break; case FS_IOC_SETFLAGS: - if (!inode_owner_or_capable(inode)) - return -EACCES; - - ret = mnt_want_write_file(file); - if (ret) - return ret; - - ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY); - if (!ret) { - ret = ovl_real_ioctl(file, cmd, arg); - - inode_lock(inode); - ovl_copyflags(ovl_inode_real(inode), inode); - inode_unlock(inode); - } - - mnt_drop_write_file(file); + ret = ovl_ioctl_set_flags(file, arg); break; default: |