Re: [PATCH 2/4] vfs: create a generic checking function for FS_IOC_FSSETXATTR

From: Jan Kara
Date: Thu Jun 20 2019 - 09:43:54 EST

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On Mon 10-06-19 21:45:49, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>

The patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> fs/btrfs/ioctl.c | 21 +++++++++-------
> fs/ext4/ioctl.c | 27 ++++++++++++++------
> fs/f2fs/file.c | 26 ++++++++++++++-----
> fs/inode.c | 17 +++++++++++++
> fs/xfs/xfs_ioctl.c | 70 ++++++++++++++++++++++++++++++----------------------
> include/linux/fs.h | 3 ++
> 6 files changed, 111 insertions(+), 53 deletions(-)
>
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index f408aa93b0cf..7ddda5b4b6a6 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -366,6 +366,13 @@ static int check_xflags(unsigned int flags)
> return 0;
> }
>
> +static void __btrfs_ioctl_fsgetxattr(struct btrfs_inode *binode,
> + struct fsxattr *fa)
> +{
> + memset(fa, 0, sizeof(*fa));
> + fa->fsx_xflags = btrfs_inode_flags_to_xflags(binode->flags);
> +}
> +
> /*
> * Set the xflags from the internal inode flags. The remaining items of fsxattr
> * are zeroed.
> @@ -375,8 +382,7 @@ 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);
> + __btrfs_ioctl_fsgetxattr(binode, &fa);
>
> if (copy_to_user(arg, &fa, sizeof(fa)))
> return -EFAULT;
> @@ -390,7 +396,7 @@ 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;
> @@ -421,13 +427,10 @@ 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;
> + __btrfs_ioctl_fsgetxattr(binode, &old_fa);
> + 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 5126ee351a84..c2f48c90ca45 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -721,6 +721,19 @@ static int ext4_ioctl_check_project(struct inode *inode, struct fsxattr *fa)
> return 0;
> }
>
> +static void ext4_fsgetxattr(struct inode *inode, struct fsxattr *fa)
> +{
> + struct ext4_inode_info *ei = EXT4_I(inode);
> +
> + 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,
> + ei->i_projid);
> + }
> +}
> +
> long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> struct inode *inode = file_inode(filp);
> @@ -1089,13 +1102,7 @@ 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_fsgetxattr(inode, &fa);
>
> if (copy_to_user((struct fsxattr __user *)arg,
> &fa, sizeof(fa)))
> @@ -1104,7 +1111,7 @@ 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 +1134,11 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> return err;
>
> inode_lock(inode);
> + ext4_fsgetxattr(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/f2fs/file.c b/fs/f2fs/file.c
> index a969d5497e03..f707de6bd4a8 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2773,19 +2773,26 @@ static inline unsigned long f2fs_xflags_to_iflags(__u32 xflags)
> return iflags;
> }
>
> -static int f2fs_ioc_fsgetxattr(struct file *filp, unsigned long arg)
> +static void __f2fs_ioc_fsgetxattr(struct inode *inode,
> + struct fsxattr *fa)
> {
> - struct inode *inode = file_inode(filp);
> struct f2fs_inode_info *fi = F2FS_I(inode);
> - struct fsxattr fa;
>
> - memset(&fa, 0, sizeof(struct fsxattr));
> - fa.fsx_xflags = f2fs_iflags_to_xflags(fi->i_flags &
> + memset(fa, 0, sizeof(struct fsxattr));
> + fa->fsx_xflags = f2fs_iflags_to_xflags(fi->i_flags &
> F2FS_FL_USER_VISIBLE);
>
> if (f2fs_sb_has_project_quota(F2FS_I_SB(inode)))
> - fa.fsx_projid = (__u32)from_kprojid(&init_user_ns,
> + fa->fsx_projid = (__u32)from_kprojid(&init_user_ns,
> fi->i_projid);
> +}
> +
> +static int f2fs_ioc_fsgetxattr(struct file *filp, unsigned long arg)
> +{
> + struct inode *inode = file_inode(filp);
> + struct fsxattr fa;
> +
> + __f2fs_ioc_fsgetxattr(inode, &fa);
>
> if (copy_to_user((struct fsxattr __user *)arg, &fa, sizeof(fa)))
> return -EFAULT;
> @@ -2820,7 +2827,7 @@ static int f2fs_ioc_fssetxattr(struct file *filp, unsigned long arg)
> {
> struct inode *inode = file_inode(filp);
> struct f2fs_inode_info *fi = F2FS_I(inode);
> - struct fsxattr fa;
> + struct fsxattr fa, old_fa;
> unsigned int flags;
> int err;
>
> @@ -2844,6 +2851,11 @@ static int f2fs_ioc_fssetxattr(struct file *filp, unsigned long arg)
>
> inode_lock(inode);
> err = f2fs_ioctl_check_project(inode, &fa);
> + if (err)
> + goto out;
> +
> + __f2fs_ioc_fsgetxattr(inode, &old_fa);
> + err = vfs_ioc_fssetxattr_check(inode, &old_fa, &fa);
> if (err)
> goto out;
> flags = (fi->i_flags & ~F2FS_FL_XFLAG_VISIBLE) |
> diff --git a/fs/inode.c b/fs/inode.c
> index 0ce60b720608..026955258a47 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2187,3 +2187,20 @@ int vfs_ioc_setflags_check(struct inode *inode, int oldflags, int flags)
> return 0;
> }
> EXPORT_SYMBOL(vfs_ioc_setflags_check);
> +
> +/* Generic function to check FS_IOC_FSSETXATTR values. */
> +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 d7dfc13f30f5..08c24f2f55c3 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -879,37 +879,45 @@ xfs_di2lxflags(
> return flags;
> }
>
> -STATIC int
> -xfs_ioc_fsgetxattr(
> - xfs_inode_t *ip,
> - int attr,
> - void __user *arg)
> +static void
> +__xfs_ioc_fsgetxattr(
> + 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 <<
> + memset(fa, 0, sizeof(struct fsxattr));
> + 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 <<
> 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_ioc_fsgetxattr(ip, attr, &fa);
> xfs_iunlock(ip, XFS_ILOCK_SHARED);
>
> if (copy_to_user(arg, &fa, sizeof(fa)))
> @@ -1035,15 +1043,6 @@ 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 +1322,7 @@ 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 +1370,6 @@ 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 +1378,11 @@ xfs_ioctl_setattr(
> goto error_trans_cancel;
> }
>
> + __xfs_ioc_fsgetxattr(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 +1493,7 @@ 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 +1529,13 @@ xfs_ioc_setxflags(
> goto out_drop_write;
> }
>
> + __xfs_ioc_fsgetxattr(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 1825d055808c..8dad3c80b611 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3548,4 +3548,7 @@ static inline struct sock *io_uring_get_socket(struct file *file)
>
> int vfs_ioc_setflags_check(struct inode *inode, int oldflags, int flags);
>
> +int vfs_ioc_fssetxattr_check(struct inode *inode, const struct fsxattr *old_fa,
> + struct fsxattr *fa);
> +
> #endif /* _LINUX_FS_H */
>
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR

Next message: Shuah Khan: "Re: [Linux-kernel-mentees] [PATCH] Documentation: platform: convert x86-laptop-drivers.txt to reST"
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