Commit ff7e0055 authored Aug 16, 2014 by Andy Lutomirski Committed by Rusty Russell Aug 16, 2014

module: Clean up ro/nx after early module load failures



The commit

    4982223e module: set nx before marking module MODULE_STATE_COMING.

introduced a regression: if a module fails to parse its arguments or
if mod_sysfs_setup fails, then the module's memory will be freed
while still read-only.  Anything that reuses that memory will crash
as soon as it tries to write to it.

Cc: stable@vger.kernel.org # v3.16
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

parent c9d26423

kernel/module.c

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -3304,6 +3304,11 @@ static int load_module(struct load_info info, const char __user uargs,
	mutex_lock(&module_mutex);		mutex_lock(&module_mutex);
	module_bug_cleanup(mod);		module_bug_cleanup(mod);
	mutex_unlock(&module_mutex);		mutex_unlock(&module_mutex);

			/* we can't deallocate the module until we clear memory protection */
			unset_module_init_ro_nx(mod);
			unset_module_core_ro_nx(mod);

	ddebug_cleanup:		ddebug_cleanup:
	dynamic_debug_remove(info->debug);		dynamic_debug_remove(info->debug);
	synchronize_sched();		synchronize_sched();

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