module: Add module name to modinfo
Accessing the mod structure (e.g. for mod->name) prior to having completed
check_modstruct_version() can result in writing garbage to the error logs
if the layout of the mod structure loaded from disk doesn't match the
running kernel's mod structure layout. This kind of mismatch will become
much more likely if a kernel is built with different randomization seed
for the struct layout randomization plugin.
Instead, add and use a new modinfo string for logging the module name.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jessica Yu <jeyu@redhat.com>
diff --git a/kernel/module.c b/kernel/module.c
index ca4509b..3803449 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -302,6 +302,7 @@
EXPORT_SYMBOL(unregister_module_notifier);
struct load_info {
+ char *name;
Elf_Ehdr *hdr;
unsigned long len;
Elf_Shdr *sechdrs;
@@ -1318,12 +1319,12 @@
}
/* Broken toolchain. Warn once, then let it go.. */
- pr_warn_once("%s: no symbol version for %s\n", mod->name, symname);
+ pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
return 1;
bad_version:
pr_warn("%s: disagrees about version of symbol %s\n",
- mod->name, symname);
+ info->name, symname);
return 0;
}
@@ -2913,9 +2914,15 @@
info->index.vers = 0; /* Pretend no __versions section! */
else
info->index.vers = find_sec(info, "__versions");
- info->index.info = find_sec(info, ".modinfo");
- info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
+
+ info->index.info = find_sec(info, ".modinfo");
+ if (!info->index.info)
+ info->name = "(missing .modinfo section)";
+ else
+ info->name = get_modinfo(info, "name");
+ info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
+
return 0;
}
@@ -2955,14 +2962,22 @@
info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
if (!info->index.mod) {
- pr_warn("No module found in object\n");
+ pr_warn("%s: No module found in object\n",
+ info->name ?: "(missing .modinfo name field)");
return ERR_PTR(-ENOEXEC);
}
/* This is temporary: point mod into copy of data. */
mod = (void *)info->sechdrs[info->index.mod].sh_addr;
+ /*
+ * If we didn't load the .modinfo 'name' field, fall back to
+ * on-disk struct mod 'name' field.
+ */
+ if (!info->name)
+ info->name = mod->name;
+
if (info->index.sym == 0) {
- pr_warn("%s: module has no symbols (stripped?)\n", mod->name);
+ pr_warn("%s: module has no symbols (stripped?)\n", info->name);
return ERR_PTR(-ENOEXEC);
}
@@ -2990,7 +3005,7 @@
return err;
} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
pr_err("%s: version magic '%s' should be '%s'\n",
- mod->name, modmagic, vermagic);
+ info->name, modmagic, vermagic);
return -ENOEXEC;
}
@@ -3270,7 +3285,7 @@
if (IS_ERR(mod))
return mod;
- if (blacklisted(mod->name))
+ if (blacklisted(info->name))
return ERR_PTR(-EPERM);
err = check_modinfo(mod, info, flags);