1 files changed, 39 insertions, 2 deletions

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 3a3ced779fc7..8a108c435bc6 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -26,6 +26,8 @@
 #include <linux/fs.h>
 #include <linux/uaccess.h>
 
+#include "internal.h"
+
 #ifdef DEBUG
 # define USE_DEBUG 1
 #else
@@ -43,6 +45,7 @@ enum {Enabled, Magic};
 #define MISC_FMT_PRESERVE_ARGV0 (1 << 31)
 #define MISC_FMT_OPEN_BINARY (1 << 30)
 #define MISC_FMT_CREDENTIALS (1 << 29)
+#define MISC_FMT_OPEN_FILE (1 << 28)
 
 typedef struct {
         struct list_head list;
@@ -54,6 +57,7 @@ typedef struct {
         char *interpreter;              /* filename of interpreter */
         char *name;
         struct dentry *dentry;
+        struct file *interp_file;
 } Node;
 
 static DEFINE_RWLOCK(entries_lock);
@@ -201,7 +205,13 @@ static int load_misc_binary(struct linux_binprm *bprm)
         if (retval < 0)
                 goto error;
 
-        interp_file = open_exec(iname);
+        if (fmt->flags & MISC_FMT_OPEN_FILE && fmt->interp_file) {
+                interp_file = filp_clone_open(fmt->interp_file);
+                if (!IS_ERR(interp_file))
+                        deny_write_access(interp_file);
+        } else {
+                interp_file = open_exec(iname);
+        }
         retval = PTR_ERR(interp_file);
         if (IS_ERR(interp_file))
                 goto error;
@@ -285,6 +295,11 @@ static char *check_special_flags(char *sfs, Node *e)
                         e->flags |= (MISC_FMT_CREDENTIALS |
                                         MISC_FMT_OPEN_BINARY);
                         break;
+                case 'F':
+                        pr_debug("register: flag: F: open interpreter file now\n");
+                        p++;
+                        e->flags |= MISC_FMT_OPEN_FILE;
+                        break;
                 default:
                         cont = 0;
                 }
@@ -543,6 +558,8 @@ static void entry_status(Node *e, char *page)
                 *dp++ = 'O';
         if (e->flags & MISC_FMT_CREDENTIALS)
                 *dp++ = 'C';
+        if (e->flags & MISC_FMT_OPEN_FILE)
+                *dp++ = 'F';
         *dp++ = '\n';
 
         if (!test_bit(Magic, &e->flags)) {
@@ -590,6 +607,11 @@ static void kill_node(Node *e)
         }
         write_unlock(&entries_lock);
 
+        if ((e->flags & MISC_FMT_OPEN_FILE) && e->interp_file) {
+                filp_close(e->interp_file, NULL);
+                e->interp_file = NULL;
+        }
+
         if (dentry) {
                 drop_nlink(d_inode(dentry));
                 d_drop(dentry);
@@ -698,6 +720,21 @@ static ssize_t bm_register_write(struct file *file, const char __user *buffer,
                 goto out2;
         }
 
+        if (e->flags & MISC_FMT_OPEN_FILE) {
+                struct file *f;
+
+                f = open_exec(e->interpreter);
+                if (IS_ERR(f)) {
+                        err = PTR_ERR(f);
+                        pr_notice("register: failed to install interpreter file %s\n", e->interpreter);
+                        simple_release_fs(&bm_mnt, &entry_count);
+                        iput(inode);
+                        inode = NULL;
+                        goto out2;
+                }
+                e->interp_file = f;
+        }
+
         e->dentry = dget(dentry);
         inode->i_private = e;
         inode->i_fop = &bm_entry_operations;
@@ -716,7 +753,7 @@ out:
 
         if (err) {
                 kfree(e);
-                return -EINVAL;
+                return err;
         }
         return count;
 }