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 85C592AE96; Tue, 29 Apr 2025 17:57:32 +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=1745949452; cv=none; b=rlOIstSZ55ffq02dPHVF2+KgzTi621f3oGZ5mW8BVOEcCinvVzdUkmzcPXbTdhsNyisHwHCOKaEZjLYjW8tRZ58pNkppNKcyxDXPgIznnFMbMlVOBEApTN4C9za2ME/xf/7e10kiJhspwmHArmC8B0siWdVe3LPLeQN2JYAsfXY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745949452; c=relaxed/simple; bh=JtdYv72pVGDV95VrpGRYu2IMTwQ32bQYHtm+Kepb+ME=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KB2dxo8mNLfrCSew2vmbdSBu8mmcdNrKziuvdCADPwArsi5o8cP1JvS+QVzgCQO4fo6F/ZejEgcMoNsVy5U5g5xFeFWJW1M1doSFehUMxN+oVGWjFkdkEEaYDajSIhqT6a15Ji4jzIdhGFgz03baTkFvnsvsW6dOphlAl1ob6W0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pPsaKbs5; 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="pPsaKbs5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F052CC4CEE3; Tue, 29 Apr 2025 17:57:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745949452; bh=JtdYv72pVGDV95VrpGRYu2IMTwQ32bQYHtm+Kepb+ME=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pPsaKbs5ksrKTRKcguMSaZRw/hYLRcxf3PVpCkJBXbfyWtyrpPdfvi25iE6MZHTUs /4ii6nEzHM+T2cxjOzaYm5SapUl0G66vBdRDTfZcxICRQQ7IdGTcYmwpJrvRd6pcx7 PfNLNJ57q7FqqsbJEyA69y7Pq9TojcqgcTCwdNiU= 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 5.15 324/373] crypto: null - Use spin lock instead of mutex Date: Tue, 29 Apr 2025 18:43:21 +0200 Message-ID: <20250429161136.464968764@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161123.119104857@linuxfoundation.org> References: <20250429161123.119104857@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 5.15-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