1 files changed, 44 insertions, 21 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 8674a390a2e8..f5e9491ef7ac 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,
@@ -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,
@@ -939,11 +957,14 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
         return check_version(sechdrs, versindex, "struct_module", mod, crc);
 }
 
-/* First part is kernel version, which we ignore. */
-static inline int same_magic(const char *amagic, const char *bmagic)
+/* First part is kernel version, which we ignore if module has crcs. */
+static inline int same_magic(const char *amagic, const char *bmagic,
+                             bool has_crcs)
 {
-        amagic += strcspn(amagic, " ");
-        bmagic += strcspn(bmagic, " ");
+        if (has_crcs) {
+                amagic += strcspn(amagic, " ");
+                bmagic += strcspn(bmagic, " ");
+        }
         return strcmp(amagic, bmagic) == 0;
 }
 #else
@@ -963,7 +984,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
         return 1;
 }
 
-static inline int same_magic(const char *amagic, const char *bmagic)
+static inline int same_magic(const char *amagic, const char *bmagic,
+                             bool has_crcs)
 {
         return strcmp(amagic, bmagic) == 0;
 }
@@ -1853,10 +1875,10 @@ 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);
-        } else if (!same_magic(modmagic, vermagic)) {
+                err = try_to_force_load(mod, "magic");
+                if (err)
+                        goto free_hdr;
+        } else if (!same_magic(modmagic, vermagic, versindex)) {
                 printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
                        mod->name, modmagic, vermagic);
                 err = -ENOEXEC;
@@ -2006,9 +2028,10 @@ 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");