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Commit a760a665 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: api - Fix module load deadlock with fallback algorithms 



With the mandatory algorithm testing at registration, we have
now created a deadlock with algorithms requiring fallbacks.
This can happen if the module containing the algorithm requiring
fallback is loaded first, without the fallback module being loaded
first.  The system will then try to test the new algorithm, find
that it needs to load a fallback, and then try to load that.

As both algorithms share the same module alias, it can attempt
to load the original algorithm again and block indefinitely.

As algorithms requiring fallbacks are a special case, we can fix
this by giving them a different module alias than the rest.  Then
it's just a matter of using the right aliases according to what
algorithms we're trying to find.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent bb402f16

arch/s390/crypto/aes_s390.c

+1 −1
Original line number Diff line number Diff line
@@ -556,7 +556,7 @@ static void __exit aes_s390_fini(void) 
module_init(aes_s390_init);

module_exit(aes_s390_fini);



MODULE_ALIAS("aes");

MODULE_ALIAS("aes-all");



MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");

MODULE_LICENSE("GPL");

crypto/api.c

+13 −2
Original line number Diff line number Diff line
@@ -215,8 +215,19 @@ struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask) 
	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);

	type &= mask;



	alg = try_then_request_module(crypto_alg_lookup(name, type, mask),

				      name);

	alg = crypto_alg_lookup(name, type, mask);

	if (!alg) {

		char tmp[CRYPTO_MAX_ALG_NAME];



		request_module(name);



		if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask) &&

		    snprintf(tmp, sizeof(tmp), "%s-all", name) < sizeof(tmp))

			request_module(tmp);



		alg = crypto_alg_lookup(name, type, mask);

	}



	if (alg)

		return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;

drivers/crypto/padlock-aes.c

+1 −1
Original line number Diff line number Diff line
@@ -489,4 +489,4 @@ MODULE_DESCRIPTION("VIA PadLock AES algorithm support"); 
MODULE_LICENSE("GPL");

MODULE_AUTHOR("Michal Ludvig");



MODULE_ALIAS("aes");
 
MODULE_ALIAS("aes-all");

drivers/crypto/padlock-sha.c

+2 −2
Original line number Diff line number Diff line
@@ -304,7 +304,7 @@ MODULE_DESCRIPTION("VIA PadLock SHA1/SHA256 algorithms support."); 
MODULE_LICENSE("GPL");

MODULE_AUTHOR("Michal Ludvig");



MODULE_ALIAS("sha1");

MODULE_ALIAS("sha256");

MODULE_ALIAS("sha1-all");

MODULE_ALIAS("sha256-all");

MODULE_ALIAS("sha1-padlock");

MODULE_ALIAS("sha256-padlock");