4.19-stable review patch. If anyone has any objections, please let me know.
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From: Wang Shilong wangshilong1991@gmail.com
commit dc7ac6c4cae3b58724c2f1e21a7c05ce19ecd5a8 upstream.
Currently, project quota could be changed by fssetxattr ioctl, and existed permission check inode_owner_or_capable() is obviously not enough, just think that common users could change project id of file, that could make users to break project quota easily.
This patch try to follow same regular of xfs project quota:
"Project Quota ID state is only allowed to change from within the init namespace. Enforce that restriction only if we are trying to change the quota ID state. Everything else is allowed in user namespaces."
Besides that, check and set project id'state should be an atomic operation, protect whole operation with inode lock, ext4_ioctl_setproject() is only used for ioctl EXT4_IOC_FSSETXATTR, we have held mnt_want_write_file() before ext4_ioctl_setflags(), and ext4_ioctl_setproject() is called after ext4_ioctl_setflags(), we could share codes, so remove it inside ext4_ioctl_setproject().
Signed-off-by: Wang Shilong wshilong@ddn.com Signed-off-by: Theodore Ts'o tytso@mit.edu Reviewed-by: Andreas Dilger adilger@dilger.ca Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/ioctl.c | 60 ++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 37 insertions(+), 23 deletions(-)
--- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -360,19 +360,14 @@ static int ext4_ioctl_setproject(struct if (projid_eq(kprojid, EXT4_I(inode)->i_projid)) return 0;
- err = mnt_want_write_file(filp); - if (err) - return err; - err = -EPERM; - inode_lock(inode); /* Is it quota file? Do not allow user to mess with it */ if (ext4_is_quota_file(inode)) - goto out_unlock; + return err;
err = ext4_get_inode_loc(inode, &iloc); if (err) - goto out_unlock; + return err;
raw_inode = ext4_raw_inode(&iloc); if (!EXT4_FITS_IN_INODE(raw_inode, ei, i_projid)) { @@ -380,7 +375,7 @@ static int ext4_ioctl_setproject(struct EXT4_SB(sb)->s_want_extra_isize, &iloc); if (err) - goto out_unlock; + return err; } else { brelse(iloc.bh); } @@ -390,10 +385,8 @@ static int ext4_ioctl_setproject(struct handle = ext4_journal_start(inode, EXT4_HT_QUOTA, EXT4_QUOTA_INIT_BLOCKS(sb) + EXT4_QUOTA_DEL_BLOCKS(sb) + 3); - if (IS_ERR(handle)) { - err = PTR_ERR(handle); - goto out_unlock; - } + if (IS_ERR(handle)) + return PTR_ERR(handle);
err = ext4_reserve_inode_write(handle, inode, &iloc); if (err) @@ -421,9 +414,6 @@ out_dirty: err = rc; out_stop: ext4_journal_stop(handle); -out_unlock: - inode_unlock(inode); - mnt_drop_write_file(filp); return err; } #else @@ -647,6 +637,30 @@ group_add_out: return err; }
+static int ext4_ioctl_check_project(struct inode *inode, struct fsxattr *fa) +{ + /* + * Project Quota ID state is only allowed to change from within the init + * namespace. Enforce that restriction only if we are trying to change + * the quota ID state. Everything else is allowed in user namespaces. + */ + if (current_user_ns() == &init_user_ns) + return 0; + + if (__kprojid_val(EXT4_I(inode)->i_projid) != fa->fsx_projid) + return -EINVAL; + + if (ext4_test_inode_flag(inode, EXT4_INODE_PROJINHERIT)) { + if (!(fa->fsx_xflags & FS_XFLAG_PROJINHERIT)) + return -EINVAL; + } else { + if (fa->fsx_xflags & FS_XFLAG_PROJINHERIT) + return -EINVAL; + } + + return 0; +} + long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); @@ -1046,19 +1060,19 @@ resizefs_out: return err;
inode_lock(inode); + err = ext4_ioctl_check_project(inode, &fa); + if (err) + goto out; flags = (ei->i_flags & ~EXT4_FL_XFLAG_VISIBLE) | (flags & EXT4_FL_XFLAG_VISIBLE); err = ext4_ioctl_setflags(inode, flags); - inode_unlock(inode); - mnt_drop_write_file(filp); if (err) - return err; - + goto out; err = ext4_ioctl_setproject(filp, fa.fsx_projid); - if (err) - return err; - - return 0; +out: + inode_unlock(inode); + mnt_drop_write_file(filp); + return err; } case EXT4_IOC_SHUTDOWN: return ext4_shutdown(sb, arg);