vfs: create a generic checking function for FS_IOC_FSSETXATTR

Create a generic checking function for the incoming FS_IOC_FSSETXATTR
fsxattr values so that we can standardize some of the implementation
behaviors.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Jan Kara <jack@suse.cz>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d3d9b4abb09b0730ed1a749f7bf1fd1aa1594842..3cd66efdb99d5ce82f09b6e3bf9ccbc20ef46a36 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -375,9 +375,7 @@ static int btrfs_ioctl_fsgetxattr(struct file *file, void __user *arg)
        struct btrfs_inode *binode = BTRFS_I(file_inode(file));
        struct fsxattr fa;
 
-       memset(&fa, 0, sizeof(fa));
-       fa.fsx_xflags = btrfs_inode_flags_to_xflags(binode->flags);
-
+       simple_fill_fsxattr(&fa, btrfs_inode_flags_to_xflags(binode->flags));
        if (copy_to_user(arg, &fa, sizeof(fa)))
                return -EFAULT;
 
@@ -390,7 +388,7 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
        struct btrfs_inode *binode = BTRFS_I(inode);
        struct btrfs_root *root = binode->root;
        struct btrfs_trans_handle *trans;
-       struct fsxattr fa;
+       struct fsxattr fa, old_fa;
        unsigned old_flags;
        unsigned old_i_flags;
        int ret = 0;
@@ -401,7 +399,6 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
        if (btrfs_root_readonly(root))
                return -EROFS;
 
-       memset(&fa, 0, sizeof(fa));
        if (copy_from_user(&fa, arg, sizeof(fa)))
                return -EFAULT;
 
@@ -421,13 +418,11 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
        old_flags = binode->flags;
        old_i_flags = inode->i_flags;
 
-       /* We need the capabilities to change append-only or immutable inode */
-       if (((old_flags & (BTRFS_INODE_APPEND | BTRFS_INODE_IMMUTABLE)) ||
-            (fa.fsx_xflags & (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE))) &&
-           !capable(CAP_LINUX_IMMUTABLE)) {
-               ret = -EPERM;
+       simple_fill_fsxattr(&old_fa,
+                           btrfs_inode_flags_to_xflags(binode->flags));
+       ret = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
+       if (ret)
                goto out_unlock;
-       }
 
        if (fa.fsx_xflags & FS_XFLAG_SYNC)
                binode->flags |= BTRFS_INODE_SYNC;

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 272b6e44191b1451027a30014ff80a727ee38bf5..1974cb755d09ee32295e97b1d5906d25d1eda65c 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -721,6 +721,17 @@ static int ext4_ioctl_check_project(struct inode *inode, struct fsxattr *fa)
        return 0;
 }
 
+static void ext4_fill_fsxattr(struct inode *inode, struct fsxattr *fa)
+{
+       struct ext4_inode_info *ei = EXT4_I(inode);
+
+       simple_fill_fsxattr(fa, ext4_iflags_to_xflags(ei->i_flags &
+                                                     EXT4_FL_USER_VISIBLE));
+
+       if (ext4_has_feature_project(inode->i_sb))
+               fa->fsx_projid = from_kprojid(&init_user_ns, ei->i_projid);
+}
+
 long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
        struct inode *inode = file_inode(filp);
@@ -1089,13 +1100,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
        {
                struct fsxattr fa;
 
-               memset(&fa, 0, sizeof(struct fsxattr));
-               fa.fsx_xflags = ext4_iflags_to_xflags(ei->i_flags & EXT4_FL_USER_VISIBLE);
-
-               if (ext4_has_feature_project(inode->i_sb)) {
-                       fa.fsx_projid = (__u32)from_kprojid(&init_user_ns,
-                               EXT4_I(inode)->i_projid);
-               }
+               ext4_fill_fsxattr(inode, &fa);
 
                if (copy_to_user((struct fsxattr __user *)arg,
                                 &fa, sizeof(fa)))
@@ -1104,7 +1109,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
        }
        case EXT4_IOC_FSSETXATTR:
        {
-               struct fsxattr fa;
+               struct fsxattr fa, old_fa;
                int err;
 
                if (copy_from_user(&fa, (struct fsxattr __user *)arg,
@@ -1127,7 +1132,11 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        return err;
 
                inode_lock(inode);
+               ext4_fill_fsxattr(inode, &old_fa);
                err = ext4_ioctl_check_project(inode, &fa);
+               if (err)
+                       goto out;
+               err = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
                if (err)
                        goto out;
                flags = (ei->i_flags & ~EXT4_FL_XFLAG_VISIBLE) |

diff --git a/fs/inode.c b/fs/inode.c
index 8072a09fd0b9673f5dd59919a71caff33352184c..ba2bafa22885568396cbb47aa99da2c7d6e1e0b4 100644 (file)
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2194,3 +2194,26 @@ int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
        return 0;
 }
 EXPORT_SYMBOL(vfs_ioc_setflags_prepare);
+
+/*
+ * Generic function to check FS_IOC_FSSETXATTR values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
+                            struct fsxattr *fa)
+{
+       /*
+        * Can't modify an immutable/append-only file unless we have
+        * appropriate permission.
+        */
+       if ((old_fa->fsx_xflags ^ fa->fsx_xflags) &
+                       (FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND) &&
+           !capable(CAP_LINUX_IMMUTABLE))
+               return -EPERM;
+
+       return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_fssetxattr_check);

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index d7dfc13f30f5a7a9828d7467f18f7737f8e40f79..458a7043b4d2536e0c48f975828dcd2ea0b2e0e0 100644 (file)
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -879,37 +879,44 @@ xfs_di2lxflags(
        return flags;
 }
 
-STATIC int
-xfs_ioc_fsgetxattr(
-       xfs_inode_t             *ip,
-       int                     attr,
-       void                    __user *arg)
+static void
+xfs_fill_fsxattr(
+       struct xfs_inode        *ip,
+       bool                    attr,
+       struct fsxattr          *fa)
 {
-       struct fsxattr          fa;
-
-       memset(&fa, 0, sizeof(struct fsxattr));
-
-       xfs_ilock(ip, XFS_ILOCK_SHARED);
-       fa.fsx_xflags = xfs_ip2xflags(ip);
-       fa.fsx_extsize = ip->i_d.di_extsize << ip->i_mount->m_sb.sb_blocklog;
-       fa.fsx_cowextsize = ip->i_d.di_cowextsize <<
+       simple_fill_fsxattr(fa, xfs_ip2xflags(ip));
+       fa->fsx_extsize = ip->i_d.di_extsize << ip->i_mount->m_sb.sb_blocklog;
+       fa->fsx_cowextsize = ip->i_d.di_cowextsize <<
                        ip->i_mount->m_sb.sb_blocklog;
-       fa.fsx_projid = xfs_get_projid(ip);
+       fa->fsx_projid = xfs_get_projid(ip);
 
        if (attr) {
                if (ip->i_afp) {
                        if (ip->i_afp->if_flags & XFS_IFEXTENTS)
-                               fa.fsx_nextents = xfs_iext_count(ip->i_afp);
+                               fa->fsx_nextents = xfs_iext_count(ip->i_afp);
                        else
-                               fa.fsx_nextents = ip->i_d.di_anextents;
+                               fa->fsx_nextents = ip->i_d.di_anextents;
                } else
-                       fa.fsx_nextents = 0;
+                       fa->fsx_nextents = 0;
        } else {
                if (ip->i_df.if_flags & XFS_IFEXTENTS)
-                       fa.fsx_nextents = xfs_iext_count(&ip->i_df);
+                       fa->fsx_nextents = xfs_iext_count(&ip->i_df);
                else
-                       fa.fsx_nextents = ip->i_d.di_nextents;
+                       fa->fsx_nextents = ip->i_d.di_nextents;
        }
+}
+
+STATIC int
+xfs_ioc_fsgetxattr(
+       xfs_inode_t             *ip,
+       int                     attr,
+       void                    __user *arg)
+{
+       struct fsxattr          fa;
+
+       xfs_ilock(ip, XFS_ILOCK_SHARED);
+       xfs_fill_fsxattr(ip, attr, &fa);
        xfs_iunlock(ip, XFS_ILOCK_SHARED);
 
        if (copy_to_user(arg, &fa, sizeof(fa)))
@@ -1035,15 +1042,6 @@ xfs_ioctl_setattr_xflags(
        if ((fa->fsx_xflags & FS_XFLAG_DAX) && xfs_is_reflink_inode(ip))
                return -EINVAL;
 
-       /*
-        * Can't modify an immutable/append-only file unless
-        * we have appropriate permission.
-        */
-       if (((ip->i_d.di_flags & (XFS_DIFLAG_IMMUTABLE | XFS_DIFLAG_APPEND)) ||
-            (fa->fsx_xflags & (FS_XFLAG_IMMUTABLE | FS_XFLAG_APPEND))) &&
-           !capable(CAP_LINUX_IMMUTABLE))
-               return -EPERM;
-
        /* diflags2 only valid for v3 inodes. */
        di_flags2 = xfs_flags2diflags2(ip, fa->fsx_xflags);
        if (di_flags2 && ip->i_d.di_version < 3)
@@ -1323,6 +1321,7 @@ xfs_ioctl_setattr(
        xfs_inode_t             *ip,
        struct fsxattr          *fa)
 {
+       struct fsxattr          old_fa;
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_trans        *tp;
        struct xfs_dquot        *udqp = NULL;
@@ -1370,7 +1369,6 @@ xfs_ioctl_setattr(
                goto error_free_dquots;
        }
 
-
        if (XFS_IS_QUOTA_RUNNING(mp) && XFS_IS_PQUOTA_ON(mp) &&
            xfs_get_projid(ip) != fa->fsx_projid) {
                code = xfs_qm_vop_chown_reserve(tp, ip, udqp, NULL, pdqp,
@@ -1379,6 +1377,11 @@ xfs_ioctl_setattr(
                        goto error_trans_cancel;
        }
 
+       xfs_fill_fsxattr(ip, false, &old_fa);
+       code = vfs_ioc_fssetxattr_check(VFS_I(ip), &old_fa, fa);
+       if (code)
+               goto error_trans_cancel;
+
        code = xfs_ioctl_setattr_check_extsize(ip, fa);
        if (code)
                goto error_trans_cancel;
@@ -1489,6 +1492,7 @@ xfs_ioc_setxflags(
 {
        struct xfs_trans        *tp;
        struct fsxattr          fa;
+       struct fsxattr          old_fa;
        unsigned int            flags;
        int                     join_flags = 0;
        int                     error;
@@ -1524,6 +1528,13 @@ xfs_ioc_setxflags(
                goto out_drop_write;
        }
 
+       xfs_fill_fsxattr(ip, false, &old_fa);
+       error = vfs_ioc_fssetxattr_check(VFS_I(ip), &old_fa, &fa);
+       if (error) {
+               xfs_trans_cancel(tp);
+               goto out_drop_write;
+       }
+
        error = xfs_ioctl_setattr_xflags(tp, ip, &fa);
        if (error) {
                xfs_trans_cancel(tp);

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 41d5175ffdd7f2156ad1b5e4978df891ee833f32..36f9691d7046d1483a69d41aaadc75b11fd21dc0 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3549,4 +3549,13 @@ static inline struct sock *io_uring_get_socket(struct file *file)
 int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
                             unsigned int flags);
 
+int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
+                            struct fsxattr *fa);
+
+static inline void simple_fill_fsxattr(struct fsxattr *fa, __u32 xflags)
+{
+       memset(fa, 0, sizeof(*fa));
+       fa->fsx_xflags = xflags;
+}
+
 #endif /* _LINUX_FS_H */