From patchwork Mon May 8 21:44:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Badhri Jagan Sridharan X-Patchwork-Id: 13235161 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75DBEC7EE22 for ; Mon, 8 May 2023 21:45:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230101AbjEHVpB (ORCPT ); Mon, 8 May 2023 17:45:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234230AbjEHVo4 (ORCPT ); Mon, 8 May 2023 17:44:56 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3875BDC for ; Mon, 8 May 2023 14:44:55 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id d2e1a72fcca58-643842c87dbso5118902b3a.1 for ; Mon, 08 May 2023 14:44:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683582295; x=1686174295; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=YWAqI/Kk7C1aWuQUx3p0nPdIT/a5Kqtc/ZwtQTnIWi4=; b=7kGs2scBYldQX+e+k2+m1q6fU/9c9u6Vb1STUfW0e1BlcplFBmLBusMn2WStRMaf/q sDAJO5hcwd7J7ZOIW+DkVpSUtojg1OfxSIMuT17etWTdyr+NBdFb2taBNCBTNN9t/YCV j1TQTmlLCc2gIydnSJFQOsbiDBghwfZBZ3mtz5XNN4MTKct/vxS6dL30ngBYPtIh1d/A jOFXWgTnZLKRG0ha1QKL+yqW91DtGOlvfHFxk12e4bWsYfUSwnPkXFZaqLi/drexzaqQ v+4tA/R/ZBRFWxjBynQJynJRKBjrvtjpmgHMMwXcO4U1z8n5GqbHgRd8YsYCtAaQ8Y2v JDTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683582295; x=1686174295; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=YWAqI/Kk7C1aWuQUx3p0nPdIT/a5Kqtc/ZwtQTnIWi4=; b=hznQAJ0fZcrEkpS7SEj+3/t8rHqRrtPpV27tt+fgrdElsHK2riKA/gGZIYqnuqfnOc V/+r1ECvwGltVoKUydo2x+7J+pRUbYYWnyFxwBcDQU6HilXx0jNsYzkHX7yk1dTAKjww EJZj8xHKPPlzaxx0esj8I/LNoejpbd2pKRRdGMdwzFkzaNhvs12rWeVluaFrzvY7ex/a 8W+2cYTgz7vv5kTI13YU/b6+YTxC4iulxOZBSTW9jYgPlycZY46V0by1fVKv6xz2XaOG Gkyc3nNusAU82YK8IoeDhQ12yhotVBnfPCYgTtNwDJkMEekHWwYgtbBslQh/WI/F+u11 Vfgw== X-Gm-Message-State: AC+VfDwLBVcR+Dd2QAegWHattwinuobuWsoFA2egtGnDDZjNg/BtuckQ TIVaIrPp31lwv+iFmGi9FXdSGBWECoQ= X-Google-Smtp-Source: ACHHUZ61341pA9qEScQl2VDXrr3EWfRPmN1j2nEY8MJxum0m00avLJW6vDpsnFV9QEBwWteJvfIlUv/R0zA= X-Received: from badhri.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:6442]) (user=badhri job=sendgmr) by 2002:a05:6a00:d68:b0:643:6fa8:e7f4 with SMTP id n40-20020a056a000d6800b006436fa8e7f4mr3494658pfv.0.1683582294746; Mon, 08 May 2023 14:44:54 -0700 (PDT) Date: Mon, 8 May 2023 21:44:43 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.40.1.521.gf1e218fcd8-goog Message-ID: <20230508214443.893436-1-badhri@google.com> Subject: [PATCH v1] usb: typec: altmodes/displayport: fix pin_assignment_show From: Badhri Jagan Sridharan To: gregkh@linuxfoundation.org, heikki.krogerus@linux.intel.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, rdbabiera@google.com, stable@vger.kernel.org, Badhri Jagan Sridharan Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org This patch fixes negative indexing of buf array in pin_assignment_show when get_current_pin_assignments returns 0 i.e. no compatible pin assignments are found. BUG: KASAN: use-after-free in pin_assignment_show+0x26c/0x33c ... Call trace: dump_backtrace+0x110/0x204 dump_stack_lvl+0x84/0xbc print_report+0x358/0x974 kasan_report+0x9c/0xfc __do_kernel_fault+0xd4/0x2d4 do_bad_area+0x48/0x168 do_tag_check_fault+0x24/0x38 do_mem_abort+0x6c/0x14c el1_abort+0x44/0x68 el1h_64_sync_handler+0x64/0xa4 el1h_64_sync+0x78/0x7c pin_assignment_show+0x26c/0x33c dev_attr_show+0x50/0xc0 Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode") Cc: stable@vger.kernel.org Signed-off-by: Badhri Jagan Sridharan Reviewed-by: Heikki Krogerus --- drivers/usb/typec/altmodes/displayport.c | 4 ++++ 1 file changed, 4 insertions(+) base-commit: ac9a78681b921877518763ba0e89202254349d1b diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c index 8f3e884222ad..66de880b28d0 100644 --- a/drivers/usb/typec/altmodes/displayport.c +++ b/drivers/usb/typec/altmodes/displayport.c @@ -516,6 +516,10 @@ static ssize_t pin_assignment_show(struct device *dev, mutex_unlock(&dp->lock); + /* get_current_pin_assignments can return 0 when no matching pin assignments are found */ + if (len == 0) + len++; + buf[len - 1] = '\n'; return len; }