Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 02/28] crypto: api - Fix race condition in larval lookup | Date | Tue, 24 Sep 2013 17:07:33 -0700 |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Herbert Xu <herbert@gondor.apana.org.au>
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>
--- crypto/api.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
--- a/crypto/api.c +++ b/crypto/api.c @@ -40,6 +40,8 @@ static inline struct crypto_alg *crypto_ return alg; } +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; @@ -150,8 +152,11 @@ static struct crypto_alg *crypto_larval_ } 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; }
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