From e85f82ff9b8ef503923a3be8ca6b5fd1908a7f3f Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Wed, 28 Jun 2017 13:41:22 +0200 Subject: [PATCH] ovl: copy-up: don't unlock between lookup and link Nothing prevents mischief on upper layer while we are busy copying up the data. Move the lookup right before the looked up dentry is actually used. Signed-off-by: Miklos Szeredi Fixes: 01ad3eb8a073 ("ovl: concurrent copy up of regular files") Cc: # v4.11 --- fs/overlayfs/copy_up.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 7a44533..ded8bfe 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -330,15 +330,9 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, .link = link }; - upper = lookup_one_len(dentry->d_name.name, upperdir, - dentry->d_name.len); - err = PTR_ERR(upper); - if (IS_ERR(upper)) - goto out; - err = security_inode_copy_up(dentry, &new_creds); if (err < 0) - goto out1; + goto out; if (new_creds) old_creds = override_creds(new_creds); @@ -362,7 +356,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, } if (err) - goto out2; + goto out; if (S_ISREG(stat->mode)) { struct path upperpath; @@ -403,6 +397,14 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, if (err) goto out_cleanup; + upper = lookup_one_len(dentry->d_name.name, upperdir, + dentry->d_name.len); + if (IS_ERR(upper)) { + err = PTR_ERR(upper); + upper = NULL; + goto out_cleanup; + } + if (tmpfile) err = ovl_do_link(temp, udir, upper, true); else @@ -416,17 +418,15 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, /* Restore timestamps on parent (best effort) */ ovl_set_timestamps(upperdir, pstat); -out2: +out: dput(temp); -out1: dput(upper); -out: return err; out_cleanup: if (!tmpfile) ovl_cleanup(wdir, temp); - goto out2; + goto out; } /* -- 2.7.4