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authorVivek Goyal <vgoyal@redhat.com>2016-07-13 10:44:52 -0400
committerPaul Moore <paul@paul-moore.com>2016-08-08 20:46:46 -0400
commit2602625b7e46576b00db619ac788c508ba3bcb2c (patch)
treea5e24e683c7a4e7cc0b93bdf4513c7601ced1966 /fs/overlayfs/dir.c
parentc957f6df52c509ccfbb96659fd1a0f7812de333f (diff)
downloadlinux-2602625b7e46576b00db619ac788c508ba3bcb2c.tar.bz2
security, overlayfs: Provide hook to correctly label newly created files
During a new file creation we need to make sure new file is created with the right label. New file is created in upper/ so effectively file should get label as if task had created file in upper/. We switched to mounter's creds for actual file creation. Also if there is a whiteout present, then file will be created in work/ dir first and then renamed in upper. In none of the cases file will be labeled as we want it to be. This patch introduces a new hook dentry_create_files_as(), which determines the label/context dentry will get if it had been created by task in upper and modify passed set of creds appropriately. Caller makes use of these new creds for file creation. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: fix whitespace issues found with checkpatch.pl] [PM: changes to use stat->mode in ovl_create_or_link()] Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'fs/overlayfs/dir.c')
-rw-r--r--fs/overlayfs/dir.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 12bcd07b9e32..a155e52db9fe 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -435,6 +435,15 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
if (override_cred) {
override_cred->fsuid = inode->i_uid;
override_cred->fsgid = inode->i_gid;
+ if (!hardlink) {
+ err = security_dentry_create_files_as(dentry,
+ stat->mode, &dentry->d_name, old_cred,
+ override_cred);
+ if (err) {
+ put_cred(override_cred);
+ goto out_revert_creds;
+ }
+ }
put_cred(override_creds(override_cred));
put_cred(override_cred);
@@ -445,6 +454,7 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
err = ovl_create_over_whiteout(dentry, inode, stat,
link, hardlink);
}
+out_revert_creds:
revert_creds(old_cred);
if (!err) {
struct inode *realinode = d_inode(ovl_dentry_upper(dentry));