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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2013-09-08 14:33:50 +1000 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2013-09-08 14:33:50 +1000 |
| commit | 77dbd7a95e4a4f15264c333a9e9ab97ee27dc2aa (patch) | |
| tree | 04a1f5c8dbe70783c35d1b378fcb73e8ddf609ea /crypto/api.c | |
| parent | 6be48f2940af9ea8d93c23a0dd8e322672c92efd (diff) | |
| download | lwn-77dbd7a95e4a4f15264c333a9e9ab97ee27dc2aa.tar.gz lwn-77dbd7a95e4a4f15264c333a9e9ab97ee27dc2aa.zip | |
crypto: api - Fix race condition in larval lookup
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.
Cc: stable@vger.kernel.org
Reported-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/api.c')
| -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 320ea4d8a0f5..a2b39c5f3649 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; } |