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authorHerbert Xu <herbert@gondor.apana.org.au>2013-09-08 14:33:50 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 17:18:01 -0700
commit139653e11c9eec4d5eff614e688d6bec99b78d7f (patch)
tree88d044524db6462cdc564fcae32fdd1051e6753f
parent13915e203f991e77eb5a52bcd4c61e5f155e3bbc (diff)
downloadlinaro-lsk-139653e11c9eec4d5eff614e688d6bec99b78d7f.tar.gz
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 <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--crypto/api.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/crypto/api.c b/crypto/api.c
index 3b6180336d3..37c4c7213de 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;
}