From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f52.google.com (mail-wr1-f52.google.com [209.85.221.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F3B113BB13D for ; Tue, 19 May 2026 20:48:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779223694; cv=none; b=FgSrgZO+9FrDicWQKP1hdbBmnvsg8mLgD+9EDl4IslLVLYXnQS1FVa9xaPdUxjJNjTpDo5m+74oo8zBhVUNWp8hGRgEz68QgKZErUJSciGCG7tcfbo02GW24htkIsTiHM4C4UlibipllKwXzZAj4G2CT2B+67gdMS1QxkNFUQBg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779223694; c=relaxed/simple; bh=wI9dECRvBX2VsI/nKiWlz/4reVpcy4qe9tjGwApazoA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Fy0UmoxXk2VSDlvucvcvzkpAUy8tPGo+2Bx+n0e2/gjs7RH/xZ7G4M5Ja9B8xCWEPmUEO1e+qGAJcDi3oVfJZfoi9ECiJKIfjlevJpVCIlYxnNbPIkb3clQojfQR0EtWyK3NINnLm4afarsWQ4xAr0z+wJt4iX9s78LYDKgkSXg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=k72eRE43; arc=none smtp.client-ip=209.85.221.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="k72eRE43" Received: by mail-wr1-f52.google.com with SMTP id ffacd0b85a97d-43d7828221bso225297f8f.3 for ; Tue, 19 May 2026 13:48:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779223691; x=1779828491; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=g1DeJFJSEHZep1pJ6wxiVEkdit9Es+ISenMHqnD6wG8=; b=k72eRE43dn/oS2DJAy+FGXgPOp8AsPyFNFjlCI4vfeG6S5hly91tuGr3uHi2P89bAz IQdbs18xMSL+1sZ1C0Bk3xahg9rnrYFD8JPgMBZoaavlB8lyIPq/FLFszfNHWhG0XmOU Gm5xF/SSu/kjL8R05pQdCZDMo8GzYtP9KThD68tX/G5sAmE5SBX9NHEF3OQAIOJ3VUPh oN7Duf3SuCnZqlydfLRcJINrU7FUl6P8qAol5CMOnyAaKDIk03JX3fYZWhCAq11MDCOz +pbnD2HsZc2c5cdRlE++iF2569z05BP8CeTc3YJecHcUz7STnTZ+DohU/fUV2u+xdAF6 yCMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779223691; x=1779828491; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=g1DeJFJSEHZep1pJ6wxiVEkdit9Es+ISenMHqnD6wG8=; b=W71h2Nb7jVIcwkTV+Ql6R3g+DuF9ShZxaE2yvqgDOJz+zeelQWcCr7rf9Myo61hvC/ SZZxrRx1wxDi/c+AmghjAP9FCw3H/x19aBfaH1Tl5elCimAuaEF0zXOZY3ClDuOx8m8k 2cuQr0Z5P34K1KpDSC06a2ZQ7894QRU65JeBtaT7ifEIYot4Ej+MWWg8Maru+vXSYazo 9F36DAyVzBAprBdXBN4g5WzbNV5qHMxv4lgwGw58lK+30mK8QkeKIA4XEwKtfHOCTkND RLWP6mSrk6ARyw8tJuTkRXu7NdSQnRvakO43k+EpNzumLnxWy+bgEebtiqFOmvOBiM7+ OfyA== X-Forwarded-Encrypted: i=1; AFNElJ/sn534hqpQXoRhbb+6CvLb2d2JxWKx5Q3HGTdPg1/LFrnMlmRkvL/GcgjQf4YtM9Cd9j/thvhXkn/OCAs=@vger.kernel.org X-Gm-Message-State: AOJu0YzHDqS1HE2geDOrRMhz1HSJjb8lYEPz6gqrQkn9bj1POrDuePxJ f2PgzaL1OTljwuXHPs4zYYQFfTQ90YymCf1ezZAy38CRfoFdbfedr8Ve X-Gm-Gg: Acq92OEqN2bjqAb4ysfEPab/eoxJclQ5ziJj4xh23A8YRszegjTbDKvihEeN3SS/vYW 6MjK+hlOdRhIhD2tNeb4Ja0Blpy1ZNRxt3jhKqSfApSic2A9r8HSRxzNSRvIxmQm1mxDa/BtO+n mWxPTDaApsmALxiVzSdDAOvNoDByZiSqfA2apl7HeRqPPzXP8Fupii8jJ/YsfOt8mc2RxySsj3x SFsUIyuGfbmrc4F79lDHIoqF7iHJYExeZIyErDsglZzXoWHhf2nktAYRX0GJaRAuGowCjGpZfd8 HnbgEzZhwQtrcAsUHrbDBHOb6WfZLMKJjfiua4PP4tJLLbwv2rs1eAszIquCu86tAx+2v2i4l/E VIok6AqJ8/xWa2MSPANTji1LspR/+8MwX3UTJ05x3f+f3dq3B200S8izY+vilVPjsFSxUsgM9OM 2mvia++jPuLF66uEWFaknNPivyuCFvOEHp8cZqAn6mipuJxdih2UYleWM30NxpKBgVguAHRu84d Q== X-Received: by 2002:a05:600c:1f8c:b0:488:abe9:86 with SMTP id 5b1f17b1804b1-48fe631817cmr157538085e9.7.1779223691288; Tue, 19 May 2026 13:48:11 -0700 (PDT) Received: from menon.v.cablecom.net (84-74-0-139.dclient.hispeed.ch. [84.74.0.139]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48fe4dac000sm356457755e9.0.2026.05.19.13.48.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 13:48:10 -0700 (PDT) From: Lothar Rubusch To: thorsten.blum@linux.dev, herbert@gondor.apana.org.au, davem@davemloft.net, nicolas.ferre@microchip.com, alexandre.belloni@bootlin.com, claudiu.beznea@tuxon.dev Cc: linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, l.rubusch@gmail.com Subject: [PATCH v2 02/12] crypto: atmel-ecc - fix use after free situation Date: Tue, 19 May 2026 20:47:53 +0000 Message-Id: <20260519204803.17034-3-l.rubusch@gmail.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260519204803.17034-1-l.rubusch@gmail.com> References: <20260519204803.17034-1-l.rubusch@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Fixes the very likely race condition, having multiple of such devices attached (identified by sashiko feedback). The Scenario: Thread A (Device 1 Probe): Successfully adds i2c_priv to the global list (Line 324). The lock is released. Thread B (An active crypto request): Concurrently calls atmel_ecc_i2c_client_alloc(). It scans the global list, sees Device 1, and assigns a crypto job to it. Thread A: Moves to line 332. crypto_register_kpp() fails (e.g., out of memory or name clash). Thread A: Enters the error path. It removes Device 1 from the list and frees the i2c_priv memory. Thread B: Is still actively trying to talk to the I2C hardware using the i2c_priv pointer it grabbed in Step 2. The memory is now gone. Result: Kernel crash (Use-After-Free). Fixes: 11105693fa05 ("crypto: atmel-ecc - introduce Microchip / Atmel ECC driver") Signed-off-by: Lothar Rubusch --- drivers/crypto/atmel-ecc.c | 12 ++++++++++++ drivers/crypto/atmel-i2c.h | 2 ++ 2 files changed, 14 insertions(+) diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c index c9f798ebf44f..19d5435aa42b 100644 --- a/drivers/crypto/atmel-ecc.c +++ b/drivers/crypto/atmel-ecc.c @@ -218,6 +218,8 @@ static struct i2c_client *atmel_ecc_i2c_client_alloc(void) list_for_each_entry(i2c_priv, &atmel_i2c_mgmt.i2c_client_list, i2c_client_list_node) { + if (!i2c_priv->ready) + continue; tfm_cnt = atomic_read(&i2c_priv->tfm_count); if (tfm_cnt < min_tfm_cnt) { min_tfm_cnt = tfm_cnt; @@ -322,6 +324,7 @@ static int atmel_ecc_probe(struct i2c_client *client) return ret; i2c_priv = i2c_get_clientdata(client); + i2c_priv->ready = false; spin_lock(&atmel_i2c_mgmt.i2c_list_lock); list_add_tail(&i2c_priv->i2c_client_list_node, @@ -336,10 +339,15 @@ static int atmel_ecc_probe(struct i2c_client *client) dev_err(&client->dev, "%s alg registration failed\n", atmel_ecdh_nist_p256.base.cra_driver_name); + return ret; } else { dev_info(&client->dev, "atmel ecc algorithms registered in /proc/crypto\n"); } + spin_lock(&atmel_i2c_mgmt.i2c_list_lock); + i2c_priv->ready = true; + spin_unlock(&atmel_i2c_mgmt.i2c_list_lock); + return ret; } @@ -347,6 +355,10 @@ static void atmel_ecc_remove(struct i2c_client *client) { struct atmel_i2c_client_priv *i2c_priv = i2c_get_clientdata(client); + spin_lock(&atmel_i2c_mgmt.i2c_list_lock); + i2c_priv->ready = false; + spin_unlock(&atmel_i2c_mgmt.i2c_list_lock); + /* Return EBUSY if i2c client already allocated. */ if (atomic_read(&i2c_priv->tfm_count)) { /* diff --git a/drivers/crypto/atmel-i2c.h b/drivers/crypto/atmel-i2c.h index 72f04c15682f..e3b12030f9c4 100644 --- a/drivers/crypto/atmel-i2c.h +++ b/drivers/crypto/atmel-i2c.h @@ -129,6 +129,7 @@ struct atmel_ecc_driver_data { * @wake_token_sz : size in bytes of the wake_token * @tfm_count : number of active crypto transformations on i2c client * @hwrng : hold the hardware generated rng + * @ready : hw client is ready to use * * Reads and writes from/to the i2c client are sequential. The first byte * transmitted to the device is treated as the byte size. Any attempt to send @@ -145,6 +146,7 @@ struct atmel_i2c_client_priv { size_t wake_token_sz; atomic_t tfm_count ____cacheline_aligned; struct hwrng hwrng; + bool ready; }; /** -- 2.39.5