[CRYPTO] cryptomgr: Fix use after free

By the time kthread_run returns the param may have already been freed
so writing the returned thread_struct pointer to param is wrong.

In fact, we don't need it in param anyway so this patch simply puts it
on the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/cryptomgr.c b/crypto/cryptomgr.c
index 6958ea83ee440e9f3425fd2aa0ff301f24ff1866..e5fb7cca5107d742ccd999bc87eaaf024a204f07 100644 (file)
--- a/crypto/cryptomgr.c
+++ b/crypto/cryptomgr.c
@@ -24,8 +24,6 @@
 #include "internal.h"
 
 struct cryptomgr_param {
-       struct task_struct *thread;
-
        struct rtattr *tb[CRYPTOA_MAX];
 
        struct {
@@ -81,6 +79,7 @@ err:
 
 static int cryptomgr_schedule_probe(struct crypto_larval *larval)
 {
+       struct task_struct *thread;
        struct cryptomgr_param *param;
        const char *name = larval->alg.cra_name;
        const char *p;
@@ -130,8 +129,8 @@ static int cryptomgr_schedule_probe(struct crypto_larval *larval)
 
        memcpy(param->larval.name, larval->alg.cra_name, CRYPTO_MAX_ALG_NAME);
 
-       param->thread = kthread_run(cryptomgr_probe, param, "cryptomgr");
-       if (IS_ERR(param->thread))
+       thread = kthread_run(cryptomgr_probe, param, "cryptomgr");
+       if (IS_ERR(thread))
                goto err_free_param;
 
        return NOTIFY_STOP;