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 312961FF1D3; Fri, 4 Apr 2025 00:06:36 +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=1743725196; cv=none; b=mHU4b/4cvmffgyUdBv3+5QjgMHSrOzZVs2UUGUUU2KWJr5VevyyvxJv6tKi2bGsktTsEMXeDfxRtXnqfT0xXsa9we34D8shANcQ8gCfuLKbkoakZQMtIEoiHWqyRrLHtbIubx0W0xPv64AAlX/KpLhjw5RyiOkJkHRSW5r9IDP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743725196; c=relaxed/simple; bh=T2lrDZMpW5FzWg6jAjAkGYig6WQSR9D3iLhX1va/tdM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=FEiEYvzoxVBLVrHjQ7A2tMPMNeAy5KST6I4h+v8ull9k4NagNCdCROdgaAOZPLOsvxig3/eEl1HAwARa04itwZ/WTgI4flavxKDG1aSruVvk9ETFoH/gMwpwnEsp2fXumcOd5RWCq6WEI8b3FxB8eAj8gkkuhCho508Ee3pyvg8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mTa+dRuk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mTa+dRuk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2ECEEC4CEE3; Fri, 4 Apr 2025 00:06:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743725196; bh=T2lrDZMpW5FzWg6jAjAkGYig6WQSR9D3iLhX1va/tdM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mTa+dRuk1vJ9Ck/bTw+QoN+oZSirxA+iXMhB3DsbDRXOyI7ga4wMGgrC2QJd6BMRs 0TDAr4+mMQlhooiPc1ugHXGfGidgyWaGpP7RVAt2U3DMS+oi2RS5FM+GjfSQ9F2qxn knLeyLqtESR0dN/w8CxvaH7gCoU2TMb2TDLKsVFaB7uJ9lObZghSCmxNcNpqRD5Msh kX/Qj2RDbKMRF5Anh/B4Xpjpa1mfR45zHweJCIexCn4kbo8Ks2XUldcbJ9+zjswmDa uQCyWI/qMSzxoNF6lZafdhCEeN5N0aU24s0tyfmDbOiiX6p0FYcyMV97sB2KGW7T4P EmzzpjbpDqoIw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Herbert Xu , syzbot+b3e02953598f447d4d2a@syzkaller.appspotmail.com, Sasha Levin , davem@davemloft.net, linux-crypto@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 04/16] crypto: null - Use spin lock instead of mutex Date: Thu, 3 Apr 2025 20:06:12 -0400 Message-Id: <20250404000624.2688940-4-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250404000624.2688940-1-sashal@kernel.org> References: <20250404000624.2688940-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.85 Content-Transfer-Encoding: 8bit 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