Merge branch 'master' into next

1 files changed, 33 insertions, 14 deletions

diff --git a/fs/exec.c b/fs/exec.c
index c5128fbc9165..639177b0eeac 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -53,6 +53,7 @@
 #include <linux/tracehook.h>
 #include <linux/kmod.h>
 #include <linux/fsnotify.h>
+#include <linux/fs_struct.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -68,17 +69,18 @@ int suid_dumpable = 0;
 static LIST_HEAD(formats);
 static DEFINE_RWLOCK(binfmt_lock);
 
-int register_binfmt(struct linux_binfmt * fmt)
+int __register_binfmt(struct linux_binfmt * fmt, int insert)
 {
         if (!fmt)
                 return -EINVAL;
         write_lock(&binfmt_lock);
-        list_add(&fmt->lh, &formats);
+        insert ? list_add(&fmt->lh, &formats) :
+                 list_add_tail(&fmt->lh, &formats);
         write_unlock(&binfmt_lock);
         return 0;       
 }
 
-EXPORT_SYMBOL(register_binfmt);
+EXPORT_SYMBOL(__register_binfmt);
 
 void unregister_binfmt(struct linux_binfmt * fmt)
 {
@@ -1056,28 +1058,35 @@ 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)
+int check_unsafe_exec(struct linux_binprm *bprm)
 {
         struct task_struct *p = current, *t;
-        unsigned long flags;
-        unsigned n_fs, n_sighand;
+        unsigned n_fs;
+        int res = 0;
 
         bprm->unsafe = tracehook_unsafe_exec(p);
 
         n_fs = 1;
-        n_sighand = 1;
-        lock_task_sighand(p, &flags);
+        write_lock(&p->fs->lock);
+        rcu_read_lock();
         for (t = next_thread(p); t != p; t = next_thread(t)) {
                 if (t->fs == p->fs)
                         n_fs++;
-                n_sighand++;
         }
+        rcu_read_unlock();
 
-        if (atomic_read(&p->fs->count) > n_fs ||
-            atomic_read(&p->sighand->count) > n_sighand)
+        if (p->fs->users > n_fs) {
                 bprm->unsafe |= LSM_UNSAFE_SHARE;
+        } else {
+                res = -EAGAIN;
+                if (!p->fs->in_exec) {
+                        p->fs->in_exec = 1;
+                        res = 1;
+                }
+        }
+        write_unlock(&p->fs->lock);
 
-        unlock_task_sighand(p, &flags);
+        return res;
 }
 
 /* 
@@ -1276,6 +1285,7 @@ int do_execve(char * filename,
         struct linux_binprm *bprm;
         struct file *file;
         struct files_struct *displaced;
+        bool clear_in_exec;
         int retval;
 
         retval = unshare_files(&displaced);
@@ -1296,12 +1306,16 @@ int do_execve(char * filename,
         bprm->cred = prepare_exec_creds();
         if (!bprm->cred)
                 goto out_unlock;
-        check_unsafe_exec(bprm);
+
+        retval = check_unsafe_exec(bprm);
+        if (retval < 0)
+                goto out_unlock;
+        clear_in_exec = retval;
 
         file = open_exec(filename);
         retval = PTR_ERR(file);
         if (IS_ERR(file))
-                goto out_unlock;
+                goto out_unmark;
 
         sched_exec();
 
@@ -1344,6 +1358,7 @@ int do_execve(char * filename,
                 goto out;
 
         /* execve succeeded */
+        current->fs->in_exec = 0;
         current->in_execve = 0;
         mutex_unlock(&current->cred_exec_mutex);
         acct_update_integrals(current);
@@ -1362,6 +1377,10 @@ out_file:
                 fput(bprm->file);
         }
 
+out_unmark:
+        if (clear_in_exec)
+                current->fs->in_exec = 0;
+
 out_unlock:
         current->in_execve = 0;
         mutex_unlock(&current->cred_exec_mutex);