linux-kernel - [PATCH 3.16 001/357] module: Clean up ro/nx after early module load failures

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Date:	Fri,  3 Oct 2014 14:26:27 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Rusty Russell <rusty@...tcorp.com.au>,
	Andy Lutomirski <luto@...capital.net>
Subject: [PATCH 3.16 001/357] module: Clean up ro/nx after early module load failures

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Andy Lutomirski <luto@...capital.net>

commit ff7e0055bb5ddbbb320cdd8dfd3e18672bddd2ad upstream.

The commit

    4982223e51e8 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: Rusty Russell <rusty@...tcorp.com.au>
Signed-off-by: Andy Lutomirski <luto@...capital.net>
Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 kernel/module.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3308,6 +3308,11 @@ static int load_module(struct load_info
 	mutex_lock(&module_mutex);
 	module_bug_cleanup(mod);
 	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:
 	dynamic_debug_remove(info->debug);
 	synchronize_sched();


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