diff options
| author | Herbert Xu <herbert@gondor.apana.org.au> | 2025-02-12 14:10:07 +0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2025-02-22 15:56:03 +0800 |
| commit | dcc47a028c24e793ce6d6efebfef1a1e92f80297 (patch) | |
| tree | 9e6f3513aca195d2bc135851d15c9d65ef51cc8e /crypto | |
| parent | 1047e21aecdf17c8a9ab9fd4bd24c6647453f93d (diff) | |
crypto: null - Use spin lock instead of mutex
As the null algorithm may be freed in softirq context through
af_alg, use spin locks instead of mutexes to protect the default
null algorithm.
Reported-by: syzbot+b3e02953598f447d4d2a@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/crypto_null.c | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/crypto/crypto_null.c b/crypto/crypto_null.c index 5b84b0f7cc17..337867028653 100644 --- a/crypto/crypto_null.c +++ b/crypto/crypto_null.c @@ -17,10 +17,10 @@ #include <crypto/internal/skcipher.h> #include <linux/init.h> #include <linux/module.h> -#include <linux/mm.h> +#include <linux/spinlock.h> #include <linux/string.h> -static DEFINE_MUTEX(crypto_default_null_skcipher_lock); +static DEFINE_SPINLOCK(crypto_default_null_skcipher_lock); static struct crypto_sync_skcipher *crypto_default_null_skcipher; static int crypto_default_null_skcipher_refcnt; @@ -152,23 +152,32 @@ MODULE_ALIAS_CRYPTO("cipher_null"); struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void) { + struct crypto_sync_skcipher *ntfm = NULL; struct crypto_sync_skcipher *tfm; - mutex_lock(&crypto_default_null_skcipher_lock); + spin_lock_bh(&crypto_default_null_skcipher_lock); tfm = crypto_default_null_skcipher; if (!tfm) { - tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0); - if (IS_ERR(tfm)) - goto unlock; - - crypto_default_null_skcipher = tfm; + spin_unlock_bh(&crypto_default_null_skcipher_lock); + + ntfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0); + if (IS_ERR(ntfm)) + return ntfm; + + spin_lock_bh(&crypto_default_null_skcipher_lock); + tfm = crypto_default_null_skcipher; + if (!tfm) { + tfm = ntfm; + ntfm = NULL; + crypto_default_null_skcipher = tfm; + } } crypto_default_null_skcipher_refcnt++; + spin_unlock_bh(&crypto_default_null_skcipher_lock); -unlock: - mutex_unlock(&crypto_default_null_skcipher_lock); + crypto_free_sync_skcipher(ntfm); return tfm; } @@ -176,12 +185,16 @@ EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher); void crypto_put_default_null_skcipher(void) { - mutex_lock(&crypto_default_null_skcipher_lock); + struct crypto_sync_skcipher *tfm = NULL; + + spin_lock_bh(&crypto_default_null_skcipher_lock); if (!--crypto_default_null_skcipher_refcnt) { - crypto_free_sync_skcipher(crypto_default_null_skcipher); + tfm = crypto_default_null_skcipher; crypto_default_null_skcipher = NULL; } - mutex_unlock(&crypto_default_null_skcipher_lock); + spin_unlock_bh(&crypto_default_null_skcipher_lock); + + crypto_free_sync_skcipher(tfm); } EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher); |