2 files changed, 38 insertions, 15 deletions

diff --git a/init/Kconfig b/init/Kconfig
index 6a44defac3ec..f0e62e5ce0dc 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -825,6 +825,15 @@ menuconfig MODULES
 
           If unsure, say Y.
 
+config MODULE_FORCE_LOAD
+        bool "Forced module loading"
+        depends on MODULES
+        default n
+        help
+          This option allows loading of modules even if that would set the
+          'F' (forced) taint, due to lack of version info.  Which is
+          usually a really bad idea.
+
 config MODULE_UNLOAD
         bool "Module unloading"
         depends on MODULES
diff --git a/kernel/module.c b/kernel/module.c
index 8674a390a2e8..8e4528c9909f 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -890,6 +890,19 @@ static struct module_attribute *modinfo_attrs[] = {
 
 static const char vermagic[] = VERMAGIC_STRING;
 
+static int try_to_force_load(struct module *mod, const char *symname)
+{
+#ifdef CONFIG_MODULE_FORCE_LOAD
+        if (!(tainted & TAINT_FORCED_MODULE))
+                printk("%s: no version for \"%s\" found: kernel tainted.\n",
+                       mod->name, symname);
+        add_taint_module(mod, TAINT_FORCED_MODULE);
+        return 0;
+#else
+        return -ENOEXEC;
+#endif
+}
+
 #ifdef CONFIG_MODVERSIONS
 static int check_version(Elf_Shdr *sechdrs,
                          unsigned int versindex,
@@ -914,18 +927,18 @@ static int check_version(Elf_Shdr *sechdrs,
 
                 if (versions[i].crc == *crc)
                         return 1;
-                printk("%s: disagrees about version of symbol %s\n",
-                       mod->name, symname);
                 DEBUGP("Found checksum %lX vs module %lX\n",
                        *crc, versions[i].crc);
-                return 0;
+                goto bad_version;
         }
-        /* Not in module's version table.  OK, but that taints the kernel. */
-        if (!(tainted & TAINT_FORCED_MODULE))
-                printk("%s: no version for \"%s\" found: kernel tainted.\n",
-                       mod->name, symname);
-        add_taint_module(mod, TAINT_FORCED_MODULE);
-        return 1;
+
+        if (!try_to_force_load(mod, symname))
+                return 1;
+
+bad_version:
+        printk("%s: disagrees about version of symbol %s\n",
+               mod->name, symname);
+        return 0;
 }
 
 static inline int check_modstruct_version(Elf_Shdr *sechdrs,
@@ -1853,9 +1866,9 @@ static struct module *load_module(void __user *umod,
         modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
         /* This is allowed: modprobe --force will invalidate it. */
         if (!modmagic) {
-                add_taint_module(mod, TAINT_FORCED_MODULE);
-                printk(KERN_WARNING "%s: no version magic, tainting kernel.\n",
-                       mod->name);
+                err = try_to_force_load(mod, "magic");
+                if (err)
+                        goto free_hdr;
         } else if (!same_magic(modmagic, vermagic)) {
                 printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
                        mod->name, modmagic, vermagic);
@@ -2006,9 +2019,10 @@ static struct module *load_module(void __user *umod,
             (mod->num_gpl_future_syms && !gplfuturecrcindex) ||
             (mod->num_unused_syms && !unusedcrcindex) ||
             (mod->num_unused_gpl_syms && !unusedgplcrcindex)) {
-                printk(KERN_WARNING "%s: No versions for exported symbols."
-                       " Tainting kernel.\n", mod->name);
-                add_taint_module(mod, TAINT_FORCED_MODULE);
+                printk(KERN_WARNING "%s: No versions for exported symbols.\n", mod->name);
+                err = try_to_force_load(mod, "nocrc");
+                if (err)
+                        goto cleanup;
         }
 #endif
         markersindex = find_sec(hdr, sechdrs, secstrings, "__markers");