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authorJoe Lawrence <joe.lawrence@redhat.com>2017-10-02 11:56:48 -0400
committerJiri Kosina <jkosina@suse.cz>2017-10-11 15:38:46 +0200
commitef8daf8eeb5b8ab6bc356656163d19f20fb827ed (patch)
tree2ae9e01115e5aa8adfe4aa3870e0cf0c156d419f /kernel
parentdcba71086e0d1abf4f00cd381530b11d0db7fa1d (diff)
downloadlinux-ef8daf8eeb5b8ab6bc356656163d19f20fb827ed.tar.bz2
livepatch: unpatch all klp_objects if klp_module_coming fails
When an incoming module is considered for livepatching by klp_module_coming(), it iterates over multiple patches and multiple kernel objects in this order: list_for_each_entry(patch, &klp_patches, list) { klp_for_each_object(patch, obj) { which means that if one of the kernel objects fails to patch, klp_module_coming()'s error path needs to unpatch and cleanup any kernel objects that were already patched by a previous patch. Reported-by: Miroslav Benes <mbenes@suse.cz> Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/livepatch/core.c60
1 files changed, 37 insertions, 23 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index b9628e43c78f..bf8c8fd72589 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -830,6 +830,41 @@ int klp_register_patch(struct klp_patch *patch)
}
EXPORT_SYMBOL_GPL(klp_register_patch);
+/*
+ * Remove parts of patches that touch a given kernel module. The list of
+ * patches processed might be limited. When limit is NULL, all patches
+ * will be handled.
+ */
+static void klp_cleanup_module_patches_limited(struct module *mod,
+ struct klp_patch *limit)
+{
+ struct klp_patch *patch;
+ struct klp_object *obj;
+
+ list_for_each_entry(patch, &klp_patches, list) {
+ if (patch == limit)
+ break;
+
+ klp_for_each_object(patch, obj) {
+ if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
+ continue;
+
+ /*
+ * Only unpatch the module if the patch is enabled or
+ * is in transition.
+ */
+ if (patch->enabled || patch == klp_transition_patch) {
+ pr_notice("reverting patch '%s' on unloading module '%s'\n",
+ patch->mod->name, obj->mod->name);
+ klp_unpatch_object(obj);
+ }
+
+ klp_free_object_loaded(obj);
+ break;
+ }
+ }
+}
+
int klp_module_coming(struct module *mod)
{
int ret;
@@ -894,7 +929,7 @@ err:
pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n",
patch->mod->name, obj->mod->name, obj->mod->name);
mod->klp_alive = false;
- klp_free_object_loaded(obj);
+ klp_cleanup_module_patches_limited(mod, patch);
mutex_unlock(&klp_mutex);
return ret;
@@ -902,9 +937,6 @@ err:
void klp_module_going(struct module *mod)
{
- struct klp_patch *patch;
- struct klp_object *obj;
-
if (WARN_ON(mod->state != MODULE_STATE_GOING &&
mod->state != MODULE_STATE_COMING))
return;
@@ -917,25 +949,7 @@ void klp_module_going(struct module *mod)
*/
mod->klp_alive = false;
- list_for_each_entry(patch, &klp_patches, list) {
- klp_for_each_object(patch, obj) {
- if (!klp_is_module(obj) || strcmp(obj->name, mod->name))
- continue;
-
- /*
- * Only unpatch the module if the patch is enabled or
- * is in transition.
- */
- if (patch->enabled || patch == klp_transition_patch) {
- pr_notice("reverting patch '%s' on unloading module '%s'\n",
- patch->mod->name, obj->mod->name);
- klp_unpatch_object(obj);
- }
-
- klp_free_object_loaded(obj);
- break;
- }
- }
+ klp_cleanup_module_patches_limited(mod, NULL);
mutex_unlock(&klp_mutex);
}