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authorAmir Goldstein <amir73il@gmail.com>2020-09-29 15:28:48 +0800
committerMiklos Szeredi <mszeredi@redhat.com>2020-10-06 15:38:15 +0200
commitbe4df0cea08a8b59eb38d73de988b7ba8022df41 (patch)
tree46ca211e654e6bb65b9a8bf7f99c9126fd8ba4f9 /fs/overlayfs
parent61536bed2149b082748f8a38c593d915ff3e5957 (diff)
ovl: use generic vfs_ioc_setflags_prepare() helper
Canonalize to ioctl FS_* flags instead of inode S_* flags. Note that we do not call the helper vfs_ioc_fssetxattr_check() for FS_IOC_FSSETXATTR ioctl. The reason is that underlying filesystem will perform all the checks. We only need to perform the capability check before overriding credentials. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/file.c62
1 files changed, 30 insertions, 32 deletions
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 443986ca564b..efccb7c1f9bc 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -559,12 +559,28 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
return ret;
}
+static unsigned int ovl_iflags_to_fsflags(unsigned int iflags)
+{
+ unsigned int flags = 0;
+
+ if (iflags & S_SYNC)
+ flags |= FS_SYNC_FL;
+ if (iflags & S_APPEND)
+ flags |= FS_APPEND_FL;
+ if (iflags & S_IMMUTABLE)
+ flags |= FS_IMMUTABLE_FL;
+ if (iflags & S_NOATIME)
+ flags |= FS_NOATIME_FL;
+
+ return flags;
+}
+
static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
- unsigned long arg, unsigned int iflags)
+ unsigned long arg, unsigned int flags)
{
long ret;
struct inode *inode = file_inode(file);
- unsigned int old_iflags;
+ unsigned int oldflags;
if (!inode_owner_or_capable(inode))
return -EACCES;
@@ -576,10 +592,9 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
inode_lock(inode);
/* Check the capability before cred override */
- ret = -EPERM;
- old_iflags = READ_ONCE(inode->i_flags);
- if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
- !capable(CAP_LINUX_IMMUTABLE))
+ oldflags = ovl_iflags_to_fsflags(READ_ONCE(inode->i_flags));
+ ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
+ if (ret)
goto unlock;
ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
@@ -598,22 +613,6 @@ unlock:
}
-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)
{
@@ -622,24 +621,23 @@ static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
if (get_user(flags, (int __user *) arg))
return -EFAULT;
- return ovl_ioctl_set_flags(file, cmd, arg,
- ovl_fsflags_to_iflags(flags));
+ return ovl_ioctl_set_flags(file, cmd, arg, flags);
}
-static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
+static unsigned int ovl_fsxflags_to_fsflags(unsigned int xflags)
{
- unsigned int iflags = 0;
+ unsigned int flags = 0;
if (xflags & FS_XFLAG_SYNC)
- iflags |= S_SYNC;
+ flags |= FS_SYNC_FL;
if (xflags & FS_XFLAG_APPEND)
- iflags |= S_APPEND;
+ flags |= FS_APPEND_FL;
if (xflags & FS_XFLAG_IMMUTABLE)
- iflags |= S_IMMUTABLE;
+ flags |= FS_IMMUTABLE_FL;
if (xflags & FS_XFLAG_NOATIME)
- iflags |= S_NOATIME;
+ flags |= FS_NOATIME_FL;
- return iflags;
+ return flags;
}
static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
@@ -652,7 +650,7 @@ static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
return -EFAULT;
return ovl_ioctl_set_flags(file, cmd, arg,
- ovl_fsxflags_to_iflags(fa.fsx_xflags));
+ ovl_fsxflags_to_fsflags(fa.fsx_xflags));
}
long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)