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authorAmir Goldstein <amir73il@gmail.com>2019-01-22 08:01:39 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2019-05-06 14:54:50 +0300
commit3428030da004a1128cbdcf93dc03e16f184d845b (patch)
treefa8bdd8c7fa12a50499519fe18123e4b271263d1 /fs/overlayfs
parente93c9c99a629c61837d5a7fc2120cd2b6c70dbdd (diff)
downloadlinux-3428030da004a1128cbdcf93dc03e16f184d845b.tar.xz
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.c6
-rw-r--r--fs/overlayfs/file.c5
-rw-r--r--fs/overlayfs/overlayfs.h2
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);