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| author | Amir Goldstein <amir73il@gmail.com> | 2019-01-22 07:01:39 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2019-05-06 13:54:50 +0200 |
| commit | 3428030da004a1128cbdcf93dc03e16f184d845b (patch) | |
| tree | fa8bdd8c7fa12a50499519fe18123e4b271263d1 /fs/overlayfs | |
| parent | e93c9c99a629c61837d5a7fc2120cd2b6c70dbdd (diff) | |
| download | linux-3428030da004a1128cbdcf93dc03e16f184d845b.tar.gz linux-3428030da004a1128cbdcf93dc03e16f184d845b.tar.bz2 linux-3428030da004a1128cbdcf93dc03e16f184d845b.zip | |
ovl: fix missing upper fs freeze protection on copy up for ioctl
Generalize the helper ovl_open_maybe_copy_up() and use it to copy up file
with data before FS_IOC_SETFLAGS ioctl.
The FS_IOC_SETFLAGS ioctl is a bit of an odd ball in vfs, which probably
caused the confusion. File may be open O_RDONLY, but ioctl modifies the
file. VFS does not call mnt_want_write_file() nor lock inode mutex, but
fs-specific code for FS_IOC_SETFLAGS does. So ovl_ioctl() calls
mnt_want_write_file() for the overlay file, and fs-specific code calls
mnt_want_write_file() for upper fs file, but there was no call for
ovl_want_write() for copy up duration which prevents overlayfs from copying
up on a frozen upper fs.
Fixes: dab5ca8fd9dd ("ovl: add lsattr/chattr support")
Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
| -rw-r--r-- | fs/overlayfs/copy_up.c | 6 | ||||
| -rw-r--r-- | fs/overlayfs/file.c | 5 | ||||
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 2 |
3 files changed, 6 insertions, 7 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 68b3303e4b46..56feaa739979 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -909,14 +909,14 @@ static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) return true; } -int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) +int ovl_maybe_copy_up(struct dentry *dentry, int flags) { int err = 0; - if (ovl_open_need_copy_up(dentry, file_flags)) { + if (ovl_open_need_copy_up(dentry, flags)) { err = ovl_want_write(dentry); if (!err) { - err = ovl_copy_up_flags(dentry, file_flags); + err = ovl_copy_up_flags(dentry, flags); ovl_drop_write(dentry); } } diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 84dd957efa24..50e4407398d8 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -116,11 +116,10 @@ static int ovl_real_fdget(const struct file *file, struct fd *real) static int ovl_open(struct inode *inode, struct file *file) { - struct dentry *dentry = file_dentry(file); struct file *realfile; int err; - err = ovl_open_maybe_copy_up(dentry, file->f_flags); + err = ovl_maybe_copy_up(file_dentry(file), file->f_flags); if (err) return err; @@ -390,7 +389,7 @@ static long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg) if (ret) return ret; - ret = ovl_copy_up_with_data(file_dentry(file)); + ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY); if (!ret) { ret = ovl_real_ioctl(file, cmd, arg); diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 9c6018287d57..d26efed9f80a 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -421,7 +421,7 @@ extern const struct file_operations ovl_file_operations; int ovl_copy_up(struct dentry *dentry); int ovl_copy_up_with_data(struct dentry *dentry); int ovl_copy_up_flags(struct dentry *dentry, int flags); -int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); +int ovl_maybe_copy_up(struct dentry *dentry, int flags); int ovl_copy_xattr(struct dentry *old, struct dentry *new); int ovl_set_attr(struct dentry *upper, struct kstat *stat); struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); |