Merge Linus master into drm-next

The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.

I've included the patch into the merge to fix the build.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 59 insertions, 29 deletions

diff --git a/fs/exec.c b/fs/exec.c
index c7f9b733406d..49a1c61433b7 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -926,10 +926,14 @@ static int de_thread(struct task_struct *tsk)
 	if (!thread_group_leader(tsk)) {
 		struct task_struct *leader = tsk->group_leader;
 
-		sig->notify_count = -1;	/* for exit_notify() */
 		for (;;) {
 			threadgroup_change_begin(tsk);
 			write_lock_irq(&tasklist_lock);
+			/*
+			 * Do this under tasklist_lock to ensure that
+			 * exit_notify() can't miss ->group_exit_task
+			 */
+			sig->notify_count = -1;
 			if (likely(leader->exit_state))
 				break;
 			__set_current_state(TASK_KILLABLE);
@@ -1078,7 +1082,13 @@ int flush_old_exec(struct linux_binprm * bprm)
 	if (retval)
 		goto out;
 
+	/*
+	 * Must be called _before_ exec_mmap() as bprm->mm is
+	 * not visibile until then. This also enables the update
+	 * to be lockless.
+	 */
 	set_mm_exe_file(bprm->mm, bprm->file);
+
 	/*
 	 * Release all of the old mmap stuff
 	 */
@@ -1265,6 +1275,53 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 	spin_unlock(&p->fs->lock);
 }
 
+static void bprm_fill_uid(struct linux_binprm *bprm)
+{
+	struct inode *inode;
+	unsigned int mode;
+	kuid_t uid;
+	kgid_t gid;
+
+	/* clear any previous set[ug]id data from a previous binary */
+	bprm->cred->euid = current_euid();
+	bprm->cred->egid = current_egid();
+
+	if (bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)
+		return;
+
+	if (task_no_new_privs(current))
+		return;
+
+	inode = file_inode(bprm->file);
+	mode = READ_ONCE(inode->i_mode);
+	if (!(mode & (S_ISUID|S_ISGID)))
+		return;
+
+	/* Be careful if suid/sgid is set */
+	mutex_lock(&inode->i_mutex);
+
+	/* reload atomically mode/uid/gid now that lock held */
+	mode = inode->i_mode;
+	uid = inode->i_uid;
+	gid = inode->i_gid;
+	mutex_unlock(&inode->i_mutex);
+
+	/* We ignore suid/sgid if there are no mappings for them in the ns */
+	if (!kuid_has_mapping(bprm->cred->user_ns, uid) ||
+		 !kgid_has_mapping(bprm->cred->user_ns, gid))
+		return;
+
+	if (mode & S_ISUID) {
+		bprm->per_clear |= PER_CLEAR_ON_SETID;
+		bprm->cred->euid = uid;
+	}
+
+	if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
+		bprm->per_clear |= PER_CLEAR_ON_SETID;
+		bprm->cred->egid = gid;
+	}
+}
+
 /*
  * Fill the binprm structure from the inode.
  * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
@@ -1273,36 +1330,9 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
  */
 int prepare_binprm(struct linux_binprm *bprm)
 {
-	struct inode *inode = file_inode(bprm->file);
-	umode_t mode = inode->i_mode;
 	int retval;
 
-
-	/* clear any previous set[ug]id data from a previous binary */
-	bprm->cred->euid = current_euid();
-	bprm->cred->egid = current_egid();
-
-	if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) &&
-	    !task_no_new_privs(current) &&
-	    kuid_has_mapping(bprm->cred->user_ns, inode->i_uid) &&
-	    kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) {
-		/* Set-uid? */
-		if (mode & S_ISUID) {
-			bprm->per_clear |= PER_CLEAR_ON_SETID;
-			bprm->cred->euid = inode->i_uid;
-		}
-
-		/* Set-gid? */
-		/*
-		 * If setgid is set but no group execute bit then this
-		 * is a candidate for mandatory locking, not a setgid
-		 * executable.
-		 */
-		if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
-			bprm->per_clear |= PER_CLEAR_ON_SETID;
-			bprm->cred->egid = inode->i_gid;
-		}
-	}
+	bprm_fill_uid(bprm);
 
 	/* fill in binprm security blob */
 	retval = security_bprm_set_creds(bprm);