module: be more picky about allowing missing module versions

[linux-2.6-omap-h63xx.git] / kernel / module.c

diff --git a/kernel/module.c b/kernel/module.c
index 8674a390a2e8262e10c6fd61a86c40f1ac2079c8..2584c0e2762d9871a490473fc279f99de1167453 100644 (file)
--- 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,
@@ -904,6 +917,10 @@ static int check_version(Elf_Shdr *sechdrs,
        if (!crc)
                return 1;
 
+       /* No versions at all?  modprobe --force does this. */
+       if (versindex == 0)
+               return try_to_force_load(mod, symname) == 0;
+
        versions = (void *) sechdrs[versindex].sh_addr;
        num_versions = sechdrs[versindex].sh_size
                / sizeof(struct modversion_info);
@@ -914,18 +931,19 @@ 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;
+
+       printk(KERN_WARNING "%s: no symbol version for %s\n",
+              mod->name, symname);
+       return 0;
+
+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 +1871,9 @@ 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 +2024,10 @@ 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");