From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.210.53 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793205907; b=XhbTQL1BmuHNzBtnHslhc1eYmG4PUbn7SvPiaP49PSUNxViVGat5/NxNTufDU/SZmNi2 GJ+n1iihUnv561oY4nFmLbBhap+IZbuAffLTET6m4XaFLMl8oCtGSXywnRYQKrq0OGLYx DJQQ29pPxsfIkZ9yZhtQjK+WKIazLVnXjFNG28IzSm8mUCzAUlY/tqoK3V84EyhfYdHno PDlbcHqVvRpZ1V4VxYR6zUaFBNgaw3YWdCztHGVTjp4omK9I8KiIhM38/0p87vA1KuqPq FRGOJyoI16Xzm5ZVB3ENB2D8urzzlC313Up8ZIo+EZOJhniM4CsfPDiMfORcecc7rmg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793205907; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Gm-Message-State:X-Gm-Gg:X-Received:Received:From:To:Cc:Subject: Date:Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=xbzTZzd6c2OHG7ATbSHtBBCffWRVoOneAxNXsMNlw6c=; b=CcgPF56qsgUL4Iw1jEzhnPyNML6ZZnPvlV8lyMxjOHVwLEXWkYEgpmy0yI4bi0mwU/DC 3+933F7f39lndwXCSL2trYSJ6TiD7y4ZzvgpfChNtqiJIMKud2HmUJSWSNrX1U507b3JQ gBXzLrGu1dlV8IjJv1Tipqvna/md62IPPhTVFW44AD8Tbaumws9vGlzpR6t0/QqTs0UYe bbv9wZ4oX9U3mTU4V5YllnCT/GDc4KmWYXTwIn3p005VZEXOWxjy6MZkrdZY35ugYg48J v4d+O70uADq5tIQXASgOPqS5/T4ZlGx4h5II//6IPFTDT4WgZVNOmkVYJXguQpbZoQg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass header.d=kernel-dk.20260707.gappssmtp.com header.i=@kernel-dk.20260707.gappssmtp.com header.a=rsa-sha256 header.s=20260707 header.b="a3/ewpdl"; arc=none smtp.remote-ip=209.85.210.53 Received: from mail-ot1-f53.google.com (mail-ot1-f53.google.com [209.85.210.53]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16765606A325 for ; Wed, 28 Oct 2026 16:45:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 16765606A325 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel-dk.20260707.gappssmtp.com header.i=@kernel-dk.20260707.gappssmtp.com header.a=rsa-sha256 header.s=20260707 header.b=a3/ewpdl Received: by mail-ot1-f53.google.com with SMTP id 46e09a7af769-8446af403b5so751697a34.2 for ; Wed, 28 Oct 2026 09:45:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20260707.gappssmtp.com; s=20260707; t=1793205906; x=1793810706; 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:content-type; bh=xbzTZzd6c2OHG7ATbSHtBBCffWRVoOneAxNXsMNlw6c=; b=a3/ewpdlsbMMwe+WRFgUPzleZNVCSG5KLIwmzvmsrRJoaQG8JtLMJ10xDkROSyinGq PbzYv/TgbuQcC+EjLg4JWV6qMwBWwNzhz3vXWGmRerl1siDOf5LAc5egXlGYkeueB+jK UF1W5n0eJ4QlVJeRo6ozF/WGhlXbGiKt/PnBwy6qVaTAZC0TSfrgGAF7dTwoyW+xakH1 IUmjKOEsMGol7spJ/p9aBCYMviDRtcyNbZbSFkOVNqr1+us39Pw2dcwQz8ps6V7eQfix j/CLslAnCjnxEXii0GJi0GWteAYhHEc4icVodrO8pjhxinBn7MHGVZ3ceoDpDISTA+Nc ziNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793205906; x=1793810706; 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:content-type; bh=xbzTZzd6c2OHG7ATbSHtBBCffWRVoOneAxNXsMNlw6c=; b=oZTmxAS84IScMYVBroiGEGTpAgNpazHlahnlJkLJU/r+rWOpgduwlWZTrl2S1mZntD Su+unksCohUdqB1+IibmUd9HYAdWssbLoXlqKJJh8Gv7pSyYv7RQoeA6RrYrk3yXlJMc aPcWcpjUYyWoGk97NQmIW2ddE78OZ5NzMoxVxS/8uI2zEXx0JjAmLX5GPzjoUA2oCkqw 6pklHHaa6WP5fWQBB2ikYZcHCTef9tHyK0EmgNNquy3SJerY81NWlVfi0UQvZL/i2CZS IACa97t7YWRlwRLjHjP5p30sCmNzkMhLKUgVOMz/+nZHEQSIMKwMyxAurLnRvOf1OceY yGHw== X-Gm-Message-State: AFq9FYJqLJEIraYQvLP4xBmb8958ovXaJhTgQVOPwnZ62yR2nA2myyLI ucBn1iWYqASpsXVLCcqyyh9StLrZmT8U0NSSfWn9UsRm38Pec1/ydPUGko+ZAiULIR85hab4oJV OJRXSZVg= X-Gm-Gg: AYBFou1HOvTI6DOHe/vPpm7HdMROnMqDfLGgRLLKYxP8I8ClkI1scyKlFvIGQcKmp0i pSbMz5nTm0T4TLbt05ARro1szqapgvY+0VMPhDwwkVv169ooVhbV4WOeMjU3WKL9D/Spje30V3J XX9GSvXTcWLHXAQrv6C4Gxsnl05PUd96HQVSWGEEPsy5F/dV6YWnk++iTdL+Go6DQV2+xSXP8uH iOUVfFETl9vO7XSiWfj5wUJbcJ22zhZQCaT+JM9v/TlyiekJGRemA5so8CoGLumpSKdJFpDK/Gq QDdZT9YWJJFik/XCehbt+yechobXeHF5t99uetABUb5Qi/Up0gqYkEsrW8YWcUjT6PN8Up48i55 yKcaTJBH9R2xEIRjF9hLERpAAjKlp/hOcSbkxzuTwu6YGIPyBSL3Ch1ccFsMukWh7tViSmiKXsl nThbAMfoAmnhBTbOouaPDYnLLxaPdiNvHZ19Qiiq/rxb78z+gKlK6gGLavqQyGIepr4im53FaQm XydaNEd8fOsTJhfFgdgZMYCfV2emdPwCDfzMbJqSXtHmMQGkmISXPONtu/kjyLajWYo9lxPEwzi /VU2Tr2CZ4B6hDiFTlvO+6ZjZQJ9k+oxlpboH4SLZx1I+zXwVz64EDD1zI5Nn0RbvRXnvvjUeg= = X-Received: by 2002:a05:6830:680f:b0:81c:a8c5:633c with SMTP id 46e09a7af769-85ab7b0d6b0mr2733885a34.17.1793205906053; Wed, 28 Oct 2026 09:45:06 -0700 (PDT) Received: from xps16 ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-85b20216828sm2416941a34.19.2026.10.28.09.45.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Oct 2026 09:45:05 -0700 (PDT) From: Jens Axboe To: linux-block@vger.kernel.org Cc: Chris Mason , "Md. Haris Iqbal" , Jack Wang , Jens Axboe Subject: [PATCH 39/98] rnbd-srv: fix use-after-free on two CLOSE messages Date: Wed, 28 Oct 2026 10:41:42 -0600 Message-ID: <20261028164415.1262013-40-axboe@kernel.dk> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028164415.1262013-1-axboe@kernel.dk> References: <20261028164415.1262013-1-axboe@kernel.dk> X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chris Mason process_msg_close() looks the sess_dev up with a kref, drops it right away, and only then takes the session mutex for the teardown. A session has several connections handled by different workers, so two CLOSE messages for the same ID both finish the lookup before either one tears the sess_dev down, and the second one works on freed memory. Any host that can open a device on the server can do that. Take the mutex first and look the ID up with xa_load() under it. The second CLOSE then finds nothing. Fixes: 2de6c8de192b ("block/rnbd: server: main functionality") Cc: "Md. Haris Iqbal" Cc: Jack Wang Signed-off-by: Chris Mason Signed-off-by: Jens Axboe --- drivers/block/rnbd/rnbd-srv.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c index 1e3de82fd70b..1cfa2c580759 100644 --- a/drivers/block/rnbd/rnbd-srv.c +++ b/drivers/block/rnbd/rnbd-srv.c @@ -360,14 +360,15 @@ static void process_msg_close(struct rnbd_srv_session *srv_sess, trace_process_msg_close(srv_sess, close_msg); - sess_dev = rnbd_get_sess_dev(le32_to_cpu(close_msg->device_id), - srv_sess); - if (IS_ERR(sess_dev)) - return; - - rnbd_put_sess_dev(sess_dev); + /* + * Each teardown of a sess_dev runs under srv_sess->lock and erases the + * ID, so an entry that is found under the lock is alive. + */ mutex_lock(&srv_sess->lock); - rnbd_srv_destroy_dev_session_sysfs(sess_dev); + sess_dev = xa_load(&srv_sess->index_idr, + le32_to_cpu(close_msg->device_id)); + if (sess_dev) + rnbd_srv_destroy_dev_session_sysfs(sess_dev); mutex_unlock(&srv_sess->lock); } -- 2.56.0