[PATCH 2/5] vfs: create a generic checking function for FS_IOC_FSSETXATTR

Darrick J. Wong
2019-06-28T18:36:12Z

From: Darrick J. Wong <darrick.wong@oracle.com>

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>
---
fs/btrfs/ioctl.c | 17 +++++--------
fs/ext4/ioctl.c | 25 +++++++++++++------
fs/f2fs/file.c | 27 ++++++++++++++------
fs/inode.c | 23 +++++++++++++++++
fs/xfs/xfs_ioctl.c | 69 ++++++++++++++++++++++++++++++----------------------
include/linux/fs.h | 9 +++++++
6 files changed, 113 insertions(+), 57 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d3d9b4abb09b..3cd66efdb99d 100644
--- 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 272b6e44191b..1974cb755d09 100644
--- 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/f2fs/file.c b/fs/f2fs/file.c
index 845ae6f43ebc..8da95b84520c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2773,19 +2773,23 @@ 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_fill_fsxattr(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 &
- F2FS_FL_USER_VISIBLE);
+ simple_fill_fsxattr(fa, 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,
- fi->i_projid);
+ fa->fsx_projid = 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_fill_fsxattr(inode, &fa);

if (copy_to_user((struct fsxattr __user *)arg, &fa, sizeof(fa)))
return -EFAULT;
@@ -2820,7 +2824,7 @@ 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 +2848,11 @@ 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_fill_fsxattr(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 9cd1b6501e97..fdd6c5d3e48d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2214,3 +2214,26 @@ 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 d7dfc13f30f5..458a7043b4d2 100644
--- 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 3f74066d3f44..91482ab4556a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3558,4 +3558,13 @@ 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 */