From: Wang Shilong Subject: [PATCH 1/2] ext4: fix setattr project check upon fssetxattr ioctl Date: Tue, 4 Sep 2018 23:54:05 +0900 Message-ID: <1536072846-19361-1-git-send-email-wshilong@ddn.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: adilger@dilger.ca, wshilong@ddn.com, dchinner@redhat.com To: linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net List-Id: linux-ext4.vger.kernel.org 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. Signed-off-by: Wang Shilong --- fs/ext4/ioctl.c | 62 ++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 39 insertions(+), 23 deletions(-) diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index a707411..e860df9 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -339,19 +339,14 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid) 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)) { @@ -359,7 +354,7 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid) EXT4_SB(sb)->s_want_extra_isize, &iloc); if (err) - goto out_unlock; + return err; } else { brelse(iloc.bh); } @@ -369,10 +364,8 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid) 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) @@ -400,9 +393,6 @@ static int ext4_ioctl_setproject(struct file *filp, __u32 projid) err = rc; out_stop: ext4_journal_stop(handle); -out_unlock: - inode_unlock(inode); - mnt_drop_write_file(filp); return err; } #else @@ -626,6 +616,32 @@ static long ext4_ioctl_group_add(struct file *file, return err; } +static int +ext4_ioctl_setattr_check_projid(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); @@ -1025,19 +1041,19 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return err; inode_lock(inode); + err = ext4_ioctl_setattr_check_projid(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); -- 1.8.3.1 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot