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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2013-09-08 14:33:50 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-09-26 17:18:01 -0700 |
| commit | 139653e11c9eec4d5eff614e688d6bec99b78d7f (patch) | |
| tree | 88d044524db6462cdc564fcae32fdd1051e6753f /crypto | |
| parent | 13915e203f991e77eb5a52bcd4c61e5f155e3bbc (diff) | |
| download | lwn-139653e11c9eec4d5eff614e688d6bec99b78d7f.tar.gz lwn-139653e11c9eec4d5eff614e688d6bec99b78d7f.zip | |
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>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/api.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/crypto/api.c b/crypto/api.c index 3b6180336d3d..37c4c7213de0 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; } |