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authorLinus Torvalds <torvalds@linux-foundation.org>2016-05-28 01:44:39 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-28 01:44:39 +0200
commit0121a32201dcc72933fb6019c41661e2f8a02fc5 (patch)
tree3e4944d4c1c7f1213413ac99f779629d67373c85 /fs/overlayfs/super.c
parentMerge branch 'for-linus-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git... (diff)
parentovl: Do d_type check only if work dir creation was successful (diff)
downloadlinux-0121a32201dcc72933fb6019c41661e2f8a02fc5.tar.xz
linux-0121a32201dcc72933fb6019c41661e2f8a02fc5.zip
Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs update from Miklos Szeredi: "The meat of this is a change to use the mounter's credentials for operations that require elevated privileges (such as whiteout creation). This fixes behavior under user namespaces as well as being a nice cleanup" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: Do d_type check only if work dir creation was successful ovl: update documentation ovl: override creds with the ones from the superblock mounter
Diffstat (limited to 'fs/overlayfs/super.c')
-rw-r--r--fs/overlayfs/super.c37
1 files changed, 28 insertions, 9 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index ed53ae0fe868..ce02f46029da 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -42,6 +42,8 @@ struct ovl_fs {
long lower_namelen;
/* pathnames of lower and upper dirs, for show_options */
struct ovl_config config;
+ /* creds of process who forced instantiation of super block */
+ const struct cred *creator_cred;
};
struct ovl_dir_cache;
@@ -265,6 +267,13 @@ bool ovl_is_whiteout(struct dentry *dentry)
return inode && IS_WHITEOUT(inode);
}
+const struct cred *ovl_override_creds(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ return override_creds(ofs->creator_cred);
+}
+
static bool ovl_is_opaquedir(struct dentry *dentry)
{
int res;
@@ -603,6 +612,7 @@ static void ovl_put_super(struct super_block *sb)
kfree(ufs->config.lowerdir);
kfree(ufs->config.upperdir);
kfree(ufs->config.workdir);
+ put_cred(ufs->creator_cred);
kfree(ufs);
}
@@ -1064,16 +1074,19 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
/*
* Upper should support d_type, else whiteouts are visible.
* Given workdir and upper are on same fs, we can do
- * iterate_dir() on workdir.
+ * iterate_dir() on workdir. This check requires successful
+ * creation of workdir in previous step.
*/
- err = ovl_check_d_type_supported(&workpath);
- if (err < 0)
- goto out_put_workdir;
+ if (ufs->workdir) {
+ err = ovl_check_d_type_supported(&workpath);
+ if (err < 0)
+ goto out_put_workdir;
- if (!err) {
- pr_err("overlayfs: upper fs needs to support d_type.\n");
- err = -EINVAL;
- goto out_put_workdir;
+ if (!err) {
+ pr_err("overlayfs: upper fs needs to support d_type.\n");
+ err = -EINVAL;
+ goto out_put_workdir;
+ }
}
}
@@ -1108,10 +1121,14 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
else
sb->s_d_op = &ovl_dentry_operations;
+ ufs->creator_cred = prepare_creds();
+ if (!ufs->creator_cred)
+ goto out_put_lower_mnt;
+
err = -ENOMEM;
oe = ovl_alloc_entry(numlower);
if (!oe)
- goto out_put_lower_mnt;
+ goto out_put_cred;
root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe));
if (!root_dentry)
@@ -1144,6 +1161,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
out_free_oe:
kfree(oe);
+out_put_cred:
+ put_cred(ufs->creator_cred);
out_put_lower_mnt:
for (i = 0; i < ufs->numlower; i++)
mntput(ufs->lower_mnt[i]);