From e2bfdde7c2d63b7774cb68dd8ee65f6b5cc43d43 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 8 Sep 2013 14:33:50 +1000 Subject: [PATCH] crypto: api - Fix race condition in larval lookup commit 77dbd7a95e4a4f15264c333a9e9ab97ee27dc2aa upstream. crypto_larval_lookup should only return a larval if it created one. Any larval created by another entity must be processed through crypto_larval_wait before being returned. Otherwise this will lead to a larval being killed twice, which will most likely lead to a crash. Reported-by: Kees Cook Tested-by: Kees Cook Signed-off-by: Herbert Xu Signed-off-by: Kamal Mostafa --- crypto/api.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/crypto/api.c b/crypto/api.c index 3b6180336d3d54..37c4c7213de070 100644 --- a/crypto/api.c +++ b/crypto/api.c @@ -34,6 +34,8 @@ EXPORT_SYMBOL_GPL(crypto_alg_sem); BLOCKING_NOTIFIER_HEAD(crypto_chain); EXPORT_SYMBOL_GPL(crypto_chain); +static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg); + struct crypto_alg *crypto_mod_get(struct crypto_alg *alg) { return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL; @@ -144,8 +146,11 @@ static struct crypto_alg *crypto_larval_add(const char *name, u32 type, } up_write(&crypto_alg_sem); - if (alg != &larval->alg) + if (alg != &larval->alg) { kfree(larval); + if (crypto_is_larval(alg)) + alg = crypto_larval_wait(alg); + } return alg; }