workdir and destdir could be the same when copying up to indexdir.
Fixes: c63e56a4a652 ("ovl: do not open/llseek lower file with upper sb_writers held")
Reported-and-tested-by: syzbot+8608bb4553edb8c78f41@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
fs/overlayfs/copy_up.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 4382881b0709..ae5eb442025d 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -731,10 +731,14 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
.rdev = c->stat.rdev,
.link = c->link
};
+ err = -EIO;
+ /* workdir and destdir could be the same when copying up to indexdir */
+ if (lock_rename(c->workdir, c->destdir) != NULL)
+ goto unlock;
err = ovl_prep_cu_creds(c->dentry, &cc);
if (err)
- return err;
+ goto unlock;
ovl_start_write(c->dentry);
inode_lock(wdir);
@@ -743,8 +747,9 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
ovl_end_write(c->dentry);
ovl_revert_cu_creds(&cc);
+ err = PTR_ERR(temp);
if (IS_ERR(temp))
- return PTR_ERR(temp);
+ goto unlock;
/*
* Copy up data first and then xattrs. Writing data after
@@ -760,10 +765,9 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
* If temp was moved, abort without the cleanup.
*/
ovl_start_write(c->dentry);
- if (lock_rename(c->workdir, c->destdir) != NULL ||
- temp->d_parent != c->workdir) {
+ if (temp->d_parent != c->workdir) {
err = -EIO;
- goto unlock;
+ goto unlockcd;
} else if (err) {
goto cleanup;
}
@@ -801,16 +805,18 @@ static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
ovl_inode_update(inode, temp);
if (S_ISDIR(inode->i_mode))
ovl_set_flag(OVL_WHITEOUTS, inode);
+
+unlockcd:
+ ovl_end_write(c->dentry);
unlock:
unlock_rename(c->workdir, c->destdir);
- ovl_end_write(c->dentry);
return err;
cleanup:
ovl_cleanup(ofs, wdir, temp);
dput(temp);
- goto unlock;
+ goto unlockcd;
}
/* Copyup using O_TMPFILE which does not require cross dir locking */
--
2.43.0
