1 files changed, 111 insertions, 90 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 929b58004b7e..172ceb6edde4 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -33,6 +33,7 @@
 #include <linux/string.h>
 #include <linux/init.h>
 #include <linux/pagemap.h>
+#include <linux/perf_counter.h>
 #include <linux/highmem.h>
 #include <linux/spinlock.h>
 #include <linux/key.h>
@@ -45,6 +46,7 @@
 #include <linux/proc_fs.h>
 #include <linux/mount.h>
 #include <linux/security.h>
+#include <linux/ima.h>
 #include <linux/syscalls.h>
 #include <linux/tsacct_kern.h>
 #include <linux/cn_proc.h>
@@ -52,6 +54,7 @@
 #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>
@@ -67,17 +70,18 @@ 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)
 {
@@ -102,37 +106,28 @@ static inline void put_binfmt(struct linux_binfmt * fmt)
 SYSCALL_DEFINE1(uselib, const char __user *, library)
 {
         struct file *file;
-        struct nameidata nd;
         char *tmp = getname(library);
         int error = PTR_ERR(tmp);
 
-        if (!IS_ERR(tmp)) {
-                error = path_lookup_open(AT_FDCWD, tmp,
-                                         LOOKUP_FOLLOW, &nd,
-                                         FMODE_READ|FMODE_EXEC);
-                putname(tmp);
-        }
-        if (error)
+        if (IS_ERR(tmp))
+                goto out;
+
+        file = do_filp_open(AT_FDCWD, tmp,
+                                O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
+                                MAY_READ | MAY_EXEC | MAY_OPEN);
+        putname(tmp);
+        error = PTR_ERR(file);
+        if (IS_ERR(file))
                 goto out;
 
         error = -EINVAL;
-        if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
+        if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
                 goto exit;
 
         error = -EACCES;
-        if (nd.path.mnt->mnt_flags & MNT_NOEXEC)
+        if (file->f_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;
-
-        file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
-        error = PTR_ERR(file);
-        if (IS_ERR(file))
-                goto out;
-
         fsnotify_open(file->f_path.dentry);
 
         error = -ENOEXEC;
@@ -154,13 +149,10 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
                 }
                 read_unlock(&binfmt_lock);
         }
+exit:
         fput(file);
 out:
         return error;
-exit:
-        release_open_intent(&nd);
-        path_put(&nd.path);
-        goto out;
 }
 
 #ifdef CONFIG_MMU
@@ -655,50 +647,39 @@ EXPORT_SYMBOL(setup_arg_pages);
 
 struct file *open_exec(const char *name)
 {
-        struct nameidata nd;
         struct file *file;
         int err;
 
-        err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd,
-                                FMODE_READ|FMODE_EXEC);
-        if (err)
+        file = do_filp_open(AT_FDCWD, name,
+                                O_LARGEFILE | O_RDONLY | FMODE_EXEC, 0,
+                                MAY_EXEC | MAY_OPEN);
+        if (IS_ERR(file))
                 goto out;
 
         err = -EACCES;
-        if (!S_ISREG(nd.path.dentry->d_inode->i_mode))
-                goto out_path_put;
-
-        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;
+        if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
+                goto exit;
 
-        file = nameidata_to_filp(&nd, O_RDONLY|O_LARGEFILE);
-        if (IS_ERR(file))
-                return file;
+        if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
+                goto exit;
 
         fsnotify_open(file->f_path.dentry);
 
         err = deny_write_access(file);
-        if (err) {
-                fput(file);
-                goto out;
-        }
+        if (err)
+                goto exit;
 
+out:
         return file;
 
- out_path_put:
-        release_open_intent(&nd);
-        path_put(&nd.path);
- out:
+exit:
+        fput(file);
         return ERR_PTR(err);
 }
 EXPORT_SYMBOL(open_exec);
 
-int kernel_read(struct file *file, unsigned long offset,
-        char *addr, unsigned long count)
+int kernel_read(struct file *file, loff_t offset,
+                char *addr, unsigned long count)
 {
         mm_segment_t old_fs;
         loff_t pos = offset;
@@ -942,6 +923,7 @@ void set_task_comm(struct task_struct *tsk, char *buf)
         task_lock(tsk);
         strlcpy(tsk->comm, buf, sizeof(tsk->comm));
         task_unlock(tsk);
+        perf_counter_comm(tsk);
 }
 
 int flush_old_exec(struct linux_binprm * bprm)
@@ -1010,6 +992,13 @@ int flush_old_exec(struct linux_binprm * bprm)
 
         current->personality &= ~bprm->per_clear;
 
+        /*
+         * Flush performance counters when crossing a
+         * security domain:
+         */
+        if (!get_dumpable(current->mm))
+                perf_counter_exit_task(current);
+
         /* An exec changes our domain. We are no longer part of the thread
            group */
 
@@ -1027,6 +1016,35 @@ out:
 EXPORT_SYMBOL(flush_old_exec);
 
 /*
+ * Prepare credentials and lock ->cred_guard_mutex.
+ * install_exec_creds() commits the new creds and drops the lock.
+ * Or, if exec fails before, free_bprm() should release ->cred and
+ * and unlock.
+ */
+int prepare_bprm_creds(struct linux_binprm *bprm)
+{
+        if (mutex_lock_interruptible(&current->cred_guard_mutex))
+                return -ERESTARTNOINTR;
+
+        bprm->cred = prepare_exec_creds();
+        if (likely(bprm->cred))
+                return 0;
+
+        mutex_unlock(&current->cred_guard_mutex);
+        return -ENOMEM;
+}
+
+void free_bprm(struct linux_binprm *bprm)
+{
+        free_arg_pages(bprm);
+        if (bprm->cred) {
+                mutex_unlock(&current->cred_guard_mutex);
+                abort_creds(bprm->cred);
+        }
+        kfree(bprm);
+}
+
+/*
  * install the new credentials for this executable
  */
 void install_exec_creds(struct linux_binprm *bprm)
@@ -1035,46 +1053,50 @@ void install_exec_creds(struct linux_binprm *bprm)
 
         commit_creds(bprm->cred);
         bprm->cred = NULL;
-
-        /* cred_exec_mutex must be held at least to this point to prevent
+        /*
+         * cred_guard_mutex must be held at least to this point to prevent
          * ptrace_attach() from altering our determination of the task's
-         * credentials; any time after this it may be unlocked */
-
+         * credentials; any time after this it may be unlocked.
+         */
         security_bprm_committed_creds(bprm);
+        mutex_unlock(&current->cred_guard_mutex);
 }
 EXPORT_SYMBOL(install_exec_creds);
 
 /*
  * determine how safe it is to execute the proposed program
- * - the caller must hold current->cred_exec_mutex to protect against
+ * - the caller must hold current->cred_guard_mutex to protect against
  *   PTRACE_ATTACH
  */
-void check_unsafe_exec(struct linux_binprm *bprm, struct files_struct *files)
+int check_unsafe_exec(struct linux_binprm *bprm)
 {
         struct task_struct *p = current, *t;
-        unsigned long flags;
-        unsigned n_fs, n_files, n_sighand;
+        unsigned n_fs;
+        int res = 0;
 
         bprm->unsafe = tracehook_unsafe_exec(p);
 
         n_fs = 1;
-        n_files = 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++;
-                if (t->files == files)
-                        n_files++;
-                n_sighand++;
         }
+        rcu_read_unlock();
 
-        if (atomic_read(&p->fs->count) > n_fs ||
-            atomic_read(&p->files->count) > n_files ||
-            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;
 }
 
 /* 
@@ -1184,6 +1206,9 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
         retval = security_bprm_check(bprm);
         if (retval)
                 return retval;
+        retval = ima_bprm_check(bprm);
+        if (retval)
+                return retval;
 
         /* kernel module loader fixup */
         /* so we don't try to load run modprobe in kernel space. */
@@ -1251,14 +1276,6 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
 
 EXPORT_SYMBOL(search_binary_handler);
 
-void free_bprm(struct linux_binprm *bprm)
-{
-        free_arg_pages(bprm);
-        if (bprm->cred)
-                abort_creds(bprm->cred);
-        kfree(bprm);
-}
-
 /*
  * sys_execve() executes a new program.
  */
@@ -1270,6 +1287,7 @@ 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);
@@ -1281,20 +1299,20 @@ int do_execve(char * filename,
         if (!bprm)
                 goto out_files;
 
-        retval = mutex_lock_interruptible(&current->cred_exec_mutex);
-        if (retval < 0)
+        retval = prepare_bprm_creds(bprm);
+        if (retval)
                 goto out_free;
 
-        retval = -ENOMEM;
-        bprm->cred = prepare_exec_creds();
-        if (!bprm->cred)
-                goto out_unlock;
-        check_unsafe_exec(bprm, displaced);
+        retval = check_unsafe_exec(bprm);
+        if (retval < 0)
+                goto out_free;
+        clear_in_exec = retval;
+        current->in_execve = 1;
 
         file = open_exec(filename);
         retval = PTR_ERR(file);
         if (IS_ERR(file))
-                goto out_unlock;
+                goto out_unmark;
 
         sched_exec();
 
@@ -1337,7 +1355,8 @@ int do_execve(char * filename,
                 goto out;
 
         /* execve succeeded */
-        mutex_unlock(&current->cred_exec_mutex);
+        current->fs->in_exec = 0;
+        current->in_execve = 0;
         acct_update_integrals(current);
         free_bprm(bprm);
         if (displaced)
@@ -1354,8 +1373,10 @@ out_file:
                 fput(bprm->file);
         }
 
-out_unlock:
-        mutex_unlock(&current->cred_exec_mutex);
+out_unmark:
+        if (clear_in_exec)
+                current->fs->in_exec = 0;
+        current->in_execve = 0;
 
 out_free:
         free_bprm(bprm);