CRED: Pass credentials through dentry_open()

Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.

The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>

19 files changed, 67 insertions, 40 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index e128ce7f0993..6296bfd9cb0b 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -323,7 +323,7 @@ static int spufs_context_open(struct dentry *dentry, struct vfsmount *mnt)
                 goto out;
         }
 
-        filp = dentry_open(dentry, mnt, O_RDONLY);
+        filp = dentry_open(dentry, mnt, O_RDONLY, current_cred());
         if (IS_ERR(filp)) {
                 put_unused_fd(ret);
                 ret = PTR_ERR(filp);
@@ -562,7 +562,7 @@ static int spufs_gang_open(struct dentry *dentry, struct vfsmount *mnt)
                 goto out;
         }
 
-        filp = dentry_open(dentry, mnt, O_RDONLY);
+        filp = dentry_open(dentry, mnt, O_RDONLY, current_cred());
         if (IS_ERR(filp)) {
                 put_unused_fd(ret);
                 ret = PTR_ERR(filp);
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 19d579d74d27..16d3b3789a50 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -159,7 +159,8 @@ void mconsole_proc(struct mc_request *req)
                 goto out_kill;
         }
 
-        file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY);
+        file = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
+                           current_cred());
         if (IS_ERR(file)) {
                 mconsole_reply(req, "Failed to open file", 1, 0);
                 goto out_kill;
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 625abf5422e2..ec16255d27dd 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -307,7 +307,8 @@ static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid)
                         goto out;
                 }
 
-                filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY);
+                filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
+                                   current_cred());
                 if (IS_ERR(filp)) {
                         err = PTR_ERR(filp);
                         goto out;
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 3504cf9df358..a75026d35d16 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -691,7 +691,8 @@ int ecryptfs_init_kthread(void);
 void ecryptfs_destroy_kthread(void);
 int ecryptfs_privileged_open(struct file **lower_file,
                              struct dentry *lower_dentry,
-                             struct vfsmount *lower_mnt);
+                             struct vfsmount *lower_mnt,
+                             const struct cred *cred);
 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry);
 
 #endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c
index c440c6b58b2d..c6d7a4d748a0 100644
--- a/fs/ecryptfs/kthread.c
+++ b/fs/ecryptfs/kthread.c
@@ -73,7 +73,7 @@ static int ecryptfs_threadfn(void *ignored)
                                 mntget(req->lower_mnt);
                                 (*req->lower_file) = dentry_open(
                                         req->lower_dentry, req->lower_mnt,
-                                        (O_RDWR | O_LARGEFILE));
+                                        (O_RDWR | O_LARGEFILE), current_cred());
                                 req->flags |= ECRYPTFS_REQ_PROCESSED;
                         }
                         wake_up(&req->wait);
@@ -132,7 +132,8 @@ void ecryptfs_destroy_kthread(void)
  */
 int ecryptfs_privileged_open(struct file **lower_file,
                              struct dentry *lower_dentry,
-                             struct vfsmount *lower_mnt)
+                             struct vfsmount *lower_mnt,
+                             const struct cred *cred)
 {
         struct ecryptfs_open_req *req;
         int rc = 0;
@@ -143,7 +144,7 @@ int ecryptfs_privileged_open(struct file **lower_file,
         dget(lower_dentry);
         mntget(lower_mnt);
         (*lower_file) = dentry_open(lower_dentry, lower_mnt,
-                                    (O_RDWR | O_LARGEFILE));
+                                    (O_RDWR | O_LARGEFILE), cred);
         if (!IS_ERR(*lower_file))
                 goto out;
         req = kmem_cache_alloc(ecryptfs_open_req_cache, GFP_KERNEL);
@@ -184,7 +185,7 @@ int ecryptfs_privileged_open(struct file **lower_file,
                 dget(lower_dentry);
                 mntget(lower_mnt);
                 (*lower_file) = dentry_open(lower_dentry, lower_mnt,
-                                            (O_RDONLY | O_LARGEFILE));
+                                            (O_RDONLY | O_LARGEFILE), cred);
                 if (IS_ERR(*lower_file)) {
                         rc = PTR_ERR(*req->lower_file);
                         (*lower_file) = NULL;
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 64d2ba980df4..fd630713c5c7 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -115,6 +115,7 @@ void __ecryptfs_printk(const char *fmt, ...)
  */
 int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 {
+        const struct cred *cred = current_cred();
         struct ecryptfs_inode_info *inode_info =
                 ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
         int rc = 0;
@@ -127,7 +128,7 @@ int ecryptfs_init_persistent_file(struct dentry *ecryptfs_dentry)
 
                 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
                 rc = ecryptfs_privileged_open(&inode_info->lower_file,
-                                                     lower_dentry, lower_mnt);
+                                              lower_dentry, lower_mnt, cred);
                 if (rc || IS_ERR(inode_info->lower_file)) {
                         printk(KERN_ERR "Error opening lower persistent file "
                                "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 80246bad1b7f..ec1fb918200f 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
+#include <linux/sched.h>
 
 #define dprintk(fmt, args...) do{}while(0)
 
@@ -249,6 +250,7 @@ static int filldir_one(void * __buf, const char * name, int len,
 static int get_name(struct vfsmount *mnt, struct dentry *dentry,
                 char *name, struct dentry *child)
 {
+        const struct cred *cred = current_cred();
         struct inode *dir = dentry->d_inode;
         int error;
         struct file *file;
@@ -263,7 +265,7 @@ static int get_name(struct vfsmount *mnt, struct dentry *dentry,
         /*
          * Open the directory ...
          */
-        file = dentry_open(dget(dentry), mntget(mnt), O_RDONLY);
+        file = dentry_open(dget(dentry), mntget(mnt), O_RDONLY, cred);
         error = PTR_ERR(file);
         if (IS_ERR(file))
                 goto out;
diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c
index 2b3d1828db99..795e2c130ad7 100644
--- a/fs/hppfs/hppfs.c
+++ b/fs/hppfs/hppfs.c
@@ -426,6 +426,7 @@ static int file_mode(int fmode)
 
 static int hppfs_open(struct inode *inode, struct file *file)
 {
+        const struct cred *cred = current_cred();
         struct hppfs_private *data;
         struct vfsmount *proc_mnt;
         struct dentry *proc_dentry;
@@ -446,7 +447,7 @@ static int hppfs_open(struct inode *inode, struct file *file)
 
         /* XXX This isn't closed anywhere */
         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
-                                      file_mode(file->f_mode));
+                                      file_mode(file->f_mode), cred);
         err = PTR_ERR(data->proc_file);
         if (IS_ERR(data->proc_file))
                 goto out_free1;
@@ -489,6 +490,7 @@ static int hppfs_open(struct inode *inode, struct file *file)
 
 static int hppfs_dir_open(struct inode *inode, struct file *file)
 {
+        const struct cred *cred = current_cred();
         struct hppfs_private *data;
         struct vfsmount *proc_mnt;
         struct dentry *proc_dentry;
@@ -502,7 +504,7 @@ static int hppfs_dir_open(struct inode *inode, struct file *file)
         proc_dentry = HPPFS_I(inode)->proc_dentry;
         proc_mnt = inode->i_sb->s_fs_info;
         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
-                                      file_mode(file->f_mode));
+                                      file_mode(file->f_mode), cred);
         err = PTR_ERR(data->proc_file);
         if (IS_ERR(data->proc_file))
                 goto out_free;
diff --git a/fs/nfsctl.c b/fs/nfsctl.c
index aed8145d9087..cc4ef2642a51 100644
--- a/fs/nfsctl.c
+++ b/fs/nfsctl.c
@@ -41,7 +41,8 @@ static struct file *do_open(char *name, int flags)
                 error = may_open(&nd, MAY_WRITE, FMODE_WRITE);
 
         if (!error)
-                return dentry_open(nd.path.dentry, nd.path.mnt, flags);
+                return dentry_open(nd.path.dentry, nd.path.mnt, flags,
+                                   current_cred());
 
         path_put(&nd.path);
         return ERR_PTR(error);
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index a5e14e8695ea..632a50b4b371 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -226,7 +226,8 @@ nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
 
         nfs4_save_user(&uid, &gid);
 
-        filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY);
+        filp = dentry_open(dget(dir), mntget(rec_dir.mnt), O_RDONLY,
+                           current_cred());
         status = PTR_ERR(filp);
         if (IS_ERR(filp))
                 goto out;
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 890d9a68c852..b59ec5a6ed24 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -671,6 +671,7 @@ __be32
 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
                         int access, struct file **filp)
 {
+        const struct cred *cred = current_cred();
         struct dentry   *dentry;
         struct inode    *inode;
         int             flags = O_RDONLY|O_LARGEFILE;
@@ -725,7 +726,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
                 DQUOT_INIT(inode);
         }
         *filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
-                                flags);
+                            flags, cred);
         if (IS_ERR(*filp))
                 host_err = PTR_ERR(*filp);
 out_nfserr:
diff --git a/fs/open.c b/fs/open.c
index b1238e195e7e..f96eaab280a3 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -783,7 +783,8 @@ static inline int __get_file_write_access(struct inode *inode,
 
 static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
                                         int flags, struct file *f,
-                                        int (*open)(struct inode *, struct file *))
+                                        int (*open)(struct inode *, struct file *),
+                                        const struct cred *cred)
 {
         struct inode *inode;
         int error;
@@ -807,7 +808,7 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
         f->f_op = fops_get(inode->i_fop);
         file_move(f, &inode->i_sb->s_files);
 
-        error = security_dentry_open(f);
+        error = security_dentry_open(f, cred);
         if (error)
                 goto cleanup_all;
 
@@ -882,6 +883,8 @@ cleanup_file:
 struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry,
                 int (*open)(struct inode *, struct file *))
 {
+        const struct cred *cred = current_cred();
+
         if (IS_ERR(nd->intent.open.file))
                 goto out;
         if (IS_ERR(dentry))
@@ -889,7 +892,7 @@ struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry
         nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt),
                                              nd->intent.open.flags - 1,
                                              nd->intent.open.file,
-                                             open);
+                                             open, cred);
 out:
         return nd->intent.open.file;
 out_err:
@@ -908,6 +911,7 @@ EXPORT_SYMBOL_GPL(lookup_instantiate_filp);
  */
 struct file *nameidata_to_filp(struct nameidata *nd, int flags)
 {
+        const struct cred *cred = current_cred();
         struct file *filp;
 
         /* Pick up the filp from the open intent */
@@ -915,7 +919,7 @@ struct file *nameidata_to_filp(struct nameidata *nd, int flags)
         /* Has the filesystem initialised the file for us? */
         if (filp->f_path.dentry == NULL)
                 filp = __dentry_open(nd->path.dentry, nd->path.mnt, flags, filp,
-                                     NULL);
+                                     NULL, cred);
         else
                 path_put(&nd->path);
         return filp;
@@ -925,7 +929,8 @@ struct file *nameidata_to_filp(struct nameidata *nd, int flags)
  * dentry_open() will have done dput(dentry) and mntput(mnt) if it returns an
  * error.
  */
-struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
+struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags,
+                         const struct cred *cred)
 {
         int error;
         struct file *f;
@@ -950,7 +955,7 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
                 return ERR_PTR(error);
         }
 
-        return __dentry_open(dentry, mnt, flags, f, NULL);
+        return __dentry_open(dentry, mnt, flags, f, NULL, cred);
 }
 EXPORT_SYMBOL(dentry_open);
 
diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 67c72aec97e6..281cbd5a25cf 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -256,6 +256,7 @@ xfs_open_by_handle(
         struct file             *parfilp,
         struct inode            *parinode)
 {
+        const struct cred       *cred = current_cred();
         int                     error;
         int                     new_fd;
         int                     permflag;
@@ -321,7 +322,7 @@ xfs_open_by_handle(
         mntget(parfilp->f_path.mnt);
 
         /* Create file pointer. */
-        filp = dentry_open(dentry, parfilp->f_path.mnt, hreq.oflags);
+        filp = dentry_open(dentry, parfilp->f_path.mnt, hreq.oflags, cred);
         if (IS_ERR(filp)) {
                 put_unused_fd(new_fd);
                 return -XFS_ERROR(-PTR_ERR(filp));
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b3d404aaabed..3bfec1327b8d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -315,6 +315,7 @@ struct poll_table_struct;
 struct kstatfs;
 struct vm_area_struct;
 struct vfsmount;
+struct cred;
 
 extern void __init inode_init(void);
 extern void __init inode_init_early(void);
@@ -1673,7 +1674,8 @@ extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
                         int mode);
 extern struct file *filp_open(const char *, int, int);
-extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);
+extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
+                                 const struct cred *);
 extern int filp_close(struct file *, fl_owner_t id);
 extern char * getname(const char __user *);
 
diff --git a/include/linux/security.h b/include/linux/security.h
index 9239cc11eb9c..7e9fe046a0d1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1402,7 +1402,7 @@ struct security_operations {
         int (*file_send_sigiotask) (struct task_struct *tsk,
                                     struct fown_struct *fown, int sig);
         int (*file_receive) (struct file *file);
-        int (*dentry_open) (struct file *file);
+        int (*dentry_open) (struct file *file, const struct cred *cred);
 
         int (*task_create) (unsigned long clone_flags);
         int (*cred_alloc_security) (struct cred *cred);
@@ -1658,7 +1658,7 @@ int security_file_set_fowner(struct file *file);
 int security_file_send_sigiotask(struct task_struct *tsk,
                                  struct fown_struct *fown, int sig);
 int security_file_receive(struct file *file);
-int security_dentry_open(struct file *file);
+int security_dentry_open(struct file *file, const struct cred *cred);
 int security_task_create(unsigned long clone_flags);
 int security_cred_alloc(struct cred *cred);
 void security_cred_free(struct cred *cred);
@@ -2171,7 +2171,8 @@ static inline int security_file_receive(struct file *file)
         return 0;
 }
 
-static inline int security_dentry_open(struct file *file)
+static inline int security_dentry_open(struct file *file,
+                                       const struct cred *cred)
 {
         return 0;
 }
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 1151881ccb9a..d9393f8e4c3e 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -594,6 +594,7 @@ static int mq_attr_ok(struct mq_attr *attr)
 static struct file *do_create(struct dentry *dir, struct dentry *dentry,
                         int oflag, mode_t mode, struct mq_attr __user *u_attr)
 {
+        const struct cred *cred = current_cred();
         struct mq_attr attr;
         struct file *result;
         int ret;
@@ -618,7 +619,7 @@ static struct file *do_create(struct dentry *dir, struct dentry *dentry,
         if (ret)
                 goto out_drop_write;
 
-        result = dentry_open(dentry, mqueue_mnt, oflag);
+        result = dentry_open(dentry, mqueue_mnt, oflag, cred);
         /*
          * dentry_open() took a persistent mnt_want_write(),
          * so we can now drop this one.
@@ -637,8 +638,10 @@ out:
 /* Opens existing queue */
 static struct file *do_open(struct dentry *dentry, int oflag)
 {
-static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
-                                        MAY_READ | MAY_WRITE };
+        const struct cred *cred = current_cred();
+
+        static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
+                                                  MAY_READ | MAY_WRITE };
 
         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
                 dput(dentry);
@@ -652,7 +655,7 @@ static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
                 return ERR_PTR(-EACCES);
         }
 
-        return dentry_open(dentry, mqueue_mnt, oflag);
+        return dentry_open(dentry, mqueue_mnt, oflag, cred);
 }
 
 asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t mode,
diff --git a/security/capability.c b/security/capability.c
index 6c4b5137ca7b..fac2f61b69a9 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -330,7 +330,7 @@ static int cap_file_receive(struct file *file)
         return 0;
 }
 
-static int cap_dentry_open(struct file *file)
+static int cap_dentry_open(struct file *file, const struct cred *cred)
 {
         return 0;
 }
diff --git a/security/security.c b/security/security.c
index d058f7d5b10a..f40a0a04c3c2 100644
--- a/security/security.c
+++ b/security/security.c
@@ -606,9 +606,9 @@ int security_file_receive(struct file *file)
         return security_ops->file_receive(file);
 }
 
-int security_dentry_open(struct file *file)
+int security_dentry_open(struct file *file, const struct cred *cred)
 {
-        return security_ops->dentry_open(file);
+        return security_ops->dentry_open(file, cred);
 }
 
 int security_task_create(unsigned long clone_flags)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index cc6e5a3f10cc..f20cbd681ba6 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2150,9 +2150,9 @@ extern struct vfsmount *selinuxfs_mount;
 extern struct dentry *selinux_null;
 
 /* Derived from fs/exec.c:flush_old_files. */
-static inline void flush_unauthorized_files(struct files_struct *files)
+static inline void flush_unauthorized_files(const struct cred *cred,
+                                            struct files_struct *files)
 {
-        const struct cred *cred = current_cred();
         struct avc_audit_data ad;
         struct file *file, *devnull = NULL;
         struct tty_struct *tty;
@@ -2222,7 +2222,10 @@ static inline void flush_unauthorized_files(struct files_struct *files)
                                         if (devnull) {
                                                 get_file(devnull);
                                         } else {
-                                                devnull = dentry_open(dget(selinux_null), mntget(selinuxfs_mount), O_RDWR);
+                                                devnull = dentry_open(
+                                                        dget(selinux_null),
+                                                        mntget(selinuxfs_mount),
+                                                        O_RDWR, cred);
                                                 if (IS_ERR(devnull)) {
                                                         devnull = NULL;
                                                         put_unused_fd(fd);
@@ -2302,6 +2305,7 @@ static void selinux_bprm_apply_creds(struct linux_binprm *bprm, int unsafe)
  */
 static void selinux_bprm_post_apply_creds(struct linux_binprm *bprm)
 {
+        const struct cred *cred = current_cred();
         struct task_security_struct *tsec;
         struct rlimit *rlim, *initrlim;
         struct itimerval itimer;
@@ -2321,7 +2325,7 @@ static void selinux_bprm_post_apply_creds(struct linux_binprm *bprm)
                 return;
 
         /* Close files for which the new task SID is not authorized. */
-        flush_unauthorized_files(current->files);
+        flush_unauthorized_files(cred, current->files);
 
         /* Check whether the new SID can inherit signal state
            from the old SID.  If not, clear itimers to avoid
@@ -3202,9 +3206,8 @@ static int selinux_file_receive(struct file *file)
         return file_has_perm(cred, file, file_to_av(file));
 }
 
-static int selinux_dentry_open(struct file *file)
+static int selinux_dentry_open(struct file *file, const struct cred *cred)
 {
-        const struct cred *cred = current_cred();
         struct file_security_struct *fsec;
         struct inode *inode;
         struct inode_security_struct *isec;