From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D77B37E110; Tue, 29 Apr 2025 17:32:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745947974; cv=none; b=GyWHVRNAcUMjdXAJ0nuNmOLV+hM7FNrP7ZZIP1ljyR3mRQ0pFOChWlxo5MMU9gRc7Iyu5d7AV1rKAmsx1oIvKjXphMiFZiwZbGVFALZnjraiupEHkc33rSN4X4FJsYJuaHLavHZKSV2UqA1AlLxpw3bPOmUDptHp1lMTLjkPbTU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745947974; c=relaxed/simple; bh=/WpuM2qTdWA0wAqjGIAEb2h1P6pC4JnFSzJSo1XqSEo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QDLnSlFM54cl8AS8ka0TkvqQFSJEhxQT8qTQzqf5/LzruEk/rrPW0Wg9yCY3cYLY/3LKsF7f19I1WdaJ/PBd/kQBcEWwZUe3RiLzkWYg53zE2PXdoNRmA8VbJGBXIWPeDO0DkQpRzaz1eXkxF/1hgV24t8Hc8tUt1cUqX06EHTA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=K0+6ioeO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="K0+6ioeO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67728C4CEE3; Tue, 29 Apr 2025 17:32:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745947974; bh=/WpuM2qTdWA0wAqjGIAEb2h1P6pC4JnFSzJSo1XqSEo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K0+6ioeO9Cos/qRlu5kKEcvigsc2LFNN5K+Smk/7kOb5d53LtD/Rz1sUItb90+Sdh hfouwtLbp3S7OFkcKi5mc/16sErBUntvPBl1OG7iwDwK5ThQOu/vh2os8Kgh+U+7kL fp46jSKW43OUYQpJ0P88jHt4yf+7SJzl7PdafHq4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+b3e02953598f447d4d2a@syzkaller.appspotmail.com, Herbert Xu , Sasha Levin Subject: [PATCH 6.12 158/280] crypto: null - Use spin lock instead of mutex Date: Tue, 29 Apr 2025 18:41:39 +0200 Message-ID: <20250429161121.584866966@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161115.008747050@linuxfoundation.org> References: <20250429161115.008747050@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu [ Upstream commit dcc47a028c24e793ce6d6efebfef1a1e92f80297 ] 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 Signed-off-by: Sasha Levin --- crypto/crypto_null.c | 39 ++++++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/crypto/crypto_null.c b/crypto/crypto_null.c index 5b84b0f7cc178..3378670286535 100644 --- a/crypto/crypto_null.c +++ b/crypto/crypto_null.c @@ -17,10 +17,10 @@ #include #include #include -#include +#include #include -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); -- 2.39.5