Make open_exec() and sys_uselib() use may_open(), instead of duplicating its parts

[safe/jmp/linux-2.6] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index 052a961..41ae8e0 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -69,17 +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)
 {
@@ -125,11 +126,7 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
        if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
                goto exit;
 
-       error = inode_permission(nd.path.dentry->d_inode,
-                                MAY_READ | MAY_EXEC | MAY_OPEN);
-       if (error)
-               goto exit;
-       error = ima_path_check(&nd.path, MAY_READ | MAY_EXEC | MAY_OPEN);
+       error = may_open(&nd.path, MAY_READ | MAY_EXEC | MAY_OPEN, 0);
        if (error)
                goto exit;
 
@@ -676,10 +673,7 @@ struct file *open_exec(const char *name)
        if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
                goto out_path_put;
 
-       err = inode_permission(nd.path.dentry->d_inode, MAY_EXEC | MAY_OPEN);
-       if (err)
-               goto out_path_put;
-       err = ima_path_check(&nd.path, MAY_EXEC | MAY_OPEN);
+       err = may_open(&nd.path, MAY_EXEC | MAY_OPEN, 0);
        if (err)
                goto out_path_put;
 
@@ -1060,7 +1054,6 @@ EXPORT_SYMBOL(install_exec_creds);
 int check_unsafe_exec(struct linux_binprm *bprm)
 {
        struct task_struct *p = current, *t;
-       unsigned long flags;
        unsigned n_fs;
        int res = 0;
 
@@ -1068,21 +1061,22 @@ int check_unsafe_exec(struct linux_binprm *bprm)
 
        n_fs = 1;
        write_lock(&p->fs->lock);
-       lock_task_sighand(p, &flags);
+       rcu_read_lock();
        for (t = next_thread(p); t != p; t = next_thread(t)) {
                if (t->fs == p->fs)
                        n_fs++;
        }
+       rcu_read_unlock();
 
        if (p->fs->users > n_fs) {
                bprm->unsafe |= LSM_UNSAFE_SHARE;
        } else {
-               if (p->fs->in_exec)
-                       res = -EAGAIN;
-               p->fs->in_exec = 1;
+               res = -EAGAIN;
+               if (!p->fs->in_exec) {
+                       p->fs->in_exec = 1;
+                       res = 1;
+               }
        }
-
-       unlock_task_sighand(p, &flags);
        write_unlock(&p->fs->lock);
 
        return res;
@@ -1284,6 +1278,7 @@ 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);
@@ -1306,8 +1301,9 @@ int do_execve(char * filename,
                goto out_unlock;
 
        retval = check_unsafe_exec(bprm);
-       if (retval)
+       if (retval < 0)
                goto out_unlock;
+       clear_in_exec = retval;
 
        file = open_exec(filename);
        retval = PTR_ERR(file);
@@ -1355,9 +1351,7 @@ int do_execve(char * filename,
                goto out;
 
        /* execve succeeded */
-       write_lock(&current->fs->lock);
        current->fs->in_exec = 0;
-       write_unlock(&current->fs->lock);
        current->in_execve = 0;
        mutex_unlock(&current->cred_exec_mutex);
        acct_update_integrals(current);
@@ -1377,9 +1371,8 @@ out_file:
        }
 
 out_unmark:
-       write_lock(&current->fs->lock);
-       current->fs->in_exec = 0;
-       write_unlock(&current->fs->lock);
+       if (clear_in_exec)
+               current->fs->in_exec = 0;
 
 out_unlock:
        current->in_execve = 0;