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Subject[PATCH 4.19 05/90] ovl: fix wrong flags check in FS_IOC_FS[SG]ETXATTR ioctls
Date
[ Upstream commit 941d935ac7636911a3fd8fa80e758e52b0b11e20 ]

The ioctl argument was parsed as the wrong type.

Fixes: b21d9c435f93 ("ovl: support the FS_IOC_FS[SG]ETXATTR ioctls")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/overlayfs/file.c | 91 ++++++++++++++++++++++++++++++++-------------
1 file changed, 65 insertions(+), 26 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 749532fd51d7..0bd276e4ccbe 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -409,37 +409,16 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
return ret;
}

-static unsigned int ovl_get_inode_flags(struct inode *inode)
-{
- unsigned int flags = READ_ONCE(inode->i_flags);
- unsigned int ovl_iflags = 0;
-
- if (flags & S_SYNC)
- ovl_iflags |= FS_SYNC_FL;
- if (flags & S_APPEND)
- ovl_iflags |= FS_APPEND_FL;
- if (flags & S_IMMUTABLE)
- ovl_iflags |= FS_IMMUTABLE_FL;
- if (flags & S_NOATIME)
- ovl_iflags |= FS_NOATIME_FL;
-
- return ovl_iflags;
-}
-
static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
- unsigned long arg)
+ unsigned long arg, unsigned int iflags)
{
long ret;
struct inode *inode = file_inode(file);
- unsigned int flags;
- unsigned int old_flags;
+ unsigned int old_iflags;

if (!inode_owner_or_capable(inode))
return -EACCES;

- if (get_user(flags, (int __user *) arg))
- return -EFAULT;
-
ret = mnt_want_write_file(file);
if (ret)
return ret;
@@ -448,8 +427,8 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,

/* Check the capability before cred override */
ret = -EPERM;
- old_flags = ovl_get_inode_flags(inode);
- if (((flags ^ old_flags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&
+ old_iflags = READ_ONCE(inode->i_flags);
+ if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
!capable(CAP_LINUX_IMMUTABLE))
goto unlock;

@@ -469,6 +448,63 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,

}

+static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
+{
+ unsigned int iflags = 0;
+
+ if (flags & FS_SYNC_FL)
+ iflags |= S_SYNC;
+ if (flags & FS_APPEND_FL)
+ iflags |= S_APPEND;
+ if (flags & FS_IMMUTABLE_FL)
+ iflags |= S_IMMUTABLE;
+ if (flags & FS_NOATIME_FL)
+ iflags |= S_NOATIME;
+
+ return iflags;
+}
+
+static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ unsigned int flags;
+
+ if (get_user(flags, (int __user *) arg))
+ return -EFAULT;
+
+ return ovl_ioctl_set_flags(file, cmd, arg,
+ ovl_fsflags_to_iflags(flags));
+}
+
+static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
+{
+ unsigned int iflags = 0;
+
+ if (xflags & FS_XFLAG_SYNC)
+ iflags |= S_SYNC;
+ if (xflags & FS_XFLAG_APPEND)
+ iflags |= S_APPEND;
+ if (xflags & FS_XFLAG_IMMUTABLE)
+ iflags |= S_IMMUTABLE;
+ if (xflags & FS_XFLAG_NOATIME)
+ iflags |= S_NOATIME;
+
+ return iflags;
+}
+
+static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct fsxattr fa;
+
+ memset(&fa, 0, sizeof(fa));
+ if (copy_from_user(&fa, (void __user *) arg, sizeof(fa)))
+ return -EFAULT;
+
+ return ovl_ioctl_set_flags(file, cmd, arg,
+ ovl_fsxflags_to_iflags(fa.fsx_xflags));
+}
+
static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
long ret;
@@ -480,8 +516,11 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
break;

case FS_IOC_SETFLAGS:
+ ret = ovl_ioctl_set_fsflags(file, cmd, arg);
+ break;
+
case FS_IOC_FSSETXATTR:
- ret = ovl_ioctl_set_flags(file, cmd, arg);
+ ret = ovl_ioctl_set_fsxflags(file, cmd, arg);
break;

default:
--
2.20.1


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