Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  CRED: Fix SUID exec regression

3 files changed, 24 insertions, 8 deletions

diff --git a/fs/compat.c b/fs/compat.c
index 65a070e..d0145ca 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1407,7 +1407,7 @@ int compat_do_execve(char * filename,
 	bprm->cred = prepare_exec_creds();
 	if (!bprm->cred)
 		goto out_unlock;
-	check_unsafe_exec(bprm);
+	check_unsafe_exec(bprm, current->files);
 
 	file = open_exec(filename);
 	retval = PTR_ERR(file);
diff --git a/fs/exec.c b/fs/exec.c
index 0dd60a0..929b580 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1049,16 +1049,32 @@ EXPORT_SYMBOL(install_exec_creds);
  * - the caller must hold current->cred_exec_mutex to protect against
  *   PTRACE_ATTACH
  */
-void check_unsafe_exec(struct linux_binprm *bprm)
+void check_unsafe_exec(struct linux_binprm *bprm, struct files_struct *files)
 {
-	struct task_struct *p = current;
+	struct task_struct *p = current, *t;
+	unsigned long flags;
+	unsigned n_fs, n_files, n_sighand;
 
 	bprm->unsafe = tracehook_unsafe_exec(p);
 
-	if (atomic_read(&p->fs->count) > 1 ||
-	    atomic_read(&p->files->count) > 1 ||
-	    atomic_read(&p->sighand->count) > 1)
+	n_fs = 1;
+	n_files = 1;
+	n_sighand = 1;
+	lock_task_sighand(p, &flags);
+	for (t = next_thread(p); t != p; t = next_thread(t)) {
+		if (t->fs == p->fs)
+			n_fs++;
+		if (t->files == files)
+			n_files++;
+		n_sighand++;
+	}
+
+	if (atomic_read(&p->fs->count) > n_fs ||
+	    atomic_read(&p->files->count) > n_files ||
+	    atomic_read(&p->sighand->count) > n_sighand)
 		bprm->unsafe |= LSM_UNSAFE_SHARE;
+
+	unlock_task_sighand(p, &flags);
 }
 
 /* 
@@ -1273,7 +1289,7 @@ int do_execve(char * filename,
 	bprm->cred = prepare_exec_creds();
 	if (!bprm->cred)
 		goto out_unlock;
-	check_unsafe_exec(bprm);
+	check_unsafe_exec(bprm, displaced);
 
 	file = open_exec(filename);
 	retval = PTR_ERR(file);
diff --git a/fs/internal.h b/fs/internal.h
index 53af885..0d8ac49 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -43,7 +43,7 @@ extern void __init chrdev_init(void);
 /*
  * exec.c
  */
-extern void check_unsafe_exec(struct linux_binprm *);
+extern void check_unsafe_exec(struct linux_binprm *, struct files_struct *);
 
 /*
  * namespace.c