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authorSeth Forshee <seth.forshee@canonical.com>2017-01-26 14:33:46 -0600
committerEric W. Biederman <ebiederm@xmission.com>2017-02-01 18:17:05 +1300
commit1328c727004d432bbdfba0ffa02a166df04c7305 (patch)
tree93c51d5133b18cfdc6660669e15e266133360d2a /fs/namei.c
parent68eb94f16227336a5773b83ecfa8290f1d6b78ce (diff)
downloadlinux-1328c727004d432bbdfba0ffa02a166df04c7305.tar.gz
vfs: open() with O_CREAT should not create inodes with unknown ids
may_create() rejects creation of inodes with ids which lack a
mapping into s_user_ns. However for O_CREAT may_o_create() is
is used instead. Add a similar check there.

Fixes: 036d523641c6 ("vfs: Don't create inodes with a uid or gid unknown to the vfs")
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/namei.c b/fs/namei.c
index ad74877e1442..6fa3e9138fe4 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2941,10 +2941,16 @@ static inline int open_to_namei_flags(int flag)
 
 static int may_o_create(const struct path *dir, struct dentry *dentry, umode_t mode)
 {
+	struct user_namespace *s_user_ns;
 	int error = security_path_mknod(dir, dentry, mode, 0);
 	if (error)
 		return error;
 
+	s_user_ns = dir->dentry->d_sb->s_user_ns;
+	if (!kuid_has_mapping(s_user_ns, current_fsuid()) ||
+	    !kgid_has_mapping(s_user_ns, current_fsgid()))
+		return -EOVERFLOW;
+
 	error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC);
 	if (error)
 		return error;