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authorPrarit Bhargava <prarit@redhat.com>2016-07-21 15:37:56 +0930
committerRusty Russell <rusty@rustcorp.com.au>2016-08-04 10:16:53 +0930
commitbe7de5f91fdc3a63ee01910c43f20db213445ce4 (patch)
treebce5a3b202a589e962cffa2f8dec3d58fbbddbc7
parent9502514f2808d29f6f2afa1c410e7808898dede1 (diff)
modules: Add kernel parameter to blacklist modules
Blacklisting a module in linux has long been a problem. The current procedure is to use rd.blacklist=module_name, however, that doesn't cover the case after the initramfs and before a boot prompt (where one is supposed to use /etc/modprobe.d/blacklist.conf to blacklist runtime loading). Using rd.shell to get an early prompt is hit-or-miss, and doesn't cover all situations AFAICT. This patch adds this functionality of permanently blacklisting a module by its name via the kernel parameter module_blacklist=module_name. [v2]: Rusty, use core_param() instead of __setup() which simplifies things. [v3]: Rusty, undo wreckage from strsep() [v4]: Rusty, simpler version of blacklisted() Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: linux-doc@vger.kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--Documentation/kernel-parameters.txt3
-rw-r--r--kernel/module.c24
2 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 724970a25666..c59ae1af02b3 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2301,6 +2301,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Note that if CONFIG_MODULE_SIG_FORCE is set, that
is always true, so this option does nothing.
+ module_blacklist= [KNL] Do not load a comma-separated list of
+ modules. Useful for debugging problem modules.
+
mousedev.tap_time=
[MOUSE] Maximum time between finger touching and
leaving touchpad surface for touch to be considered
diff --git a/kernel/module.c b/kernel/module.c
index beaebea627ff..c91c2fdca2e6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3168,6 +3168,27 @@ int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
return 0;
}
+/* module_blacklist is a comma-separated list of module names */
+static char *module_blacklist;
+static bool blacklisted(char *module_name)
+{
+ const char *p;
+ size_t len;
+
+ if (!module_blacklist)
+ return false;
+
+ for (p = module_blacklist; *p; p += len) {
+ len = strcspn(p, ",");
+ if (strlen(module_name) == len && !memcmp(module_name, p, len))
+ return true;
+ if (p[len] == ',')
+ len++;
+ }
+ return false;
+}
+core_param(module_blacklist, module_blacklist, charp, 0400);
+
static struct module *layout_and_allocate(struct load_info *info, int flags)
{
/* Module within temporary copy. */
@@ -3178,6 +3199,9 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
if (IS_ERR(mod))
return mod;
+ if (blacklisted(mod->name))
+ return ERR_PTR(-EPERM);
+
err = check_modinfo(mod, info, flags);
if (err)
return ERR_PTR(err);