From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yx1-f50.google.com (mail-yx1-f50.google.com [74.125.224.50]) (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 B2F4E220F2A for ; Fri, 28 Aug 2026 04:19:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.224.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787890772; cv=none; b=jbLSzpTixXeD7U+3Sjao2axmh31Lt7Y/lFrXqNiC1rktMjK1xbaSZJw/GSQSwRz6enigIs2K3XwYSR3E/3PUT2BpAlWIDUnVacbuE/by5KyS/NAbiv+1cJ6x3zM59F4CXOWe+YMK/zhOxiAQ5IJKZP8P9qv//1NB/lwW9DWSfBg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787890772; c=relaxed/simple; bh=8TnsSCO6rRn51bAw5WulNUp6C1eYkXeVIKjsJTUUS5w=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=CdUjCqc5uMiZ00XQvFd+SLu9+9lxrw9RXuxt9tZtM/qaLYVspeEAvnifjfC59H1Muuxoprb8favabvINnRcNUILszpLCw0+AhCFypfFaKezg4WA7fGiYC4EypNA5GwxUXOjgjEdqMy7W12B0qBYq9aMVNJ2E/sqX/tas4OsvfZI= 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=Kge2OCCp; arc=none smtp.client-ip=74.125.224.50 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="Kge2OCCp" Received: by mail-yx1-f50.google.com with SMTP id 956f58d0204a3-66e452df0easo771316d50.1 for ; Thu, 27 Aug 2026 21:19:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787890770; x=1788495570; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=GvQBCeK2pDC31wjSOrIf5IPUWWi4fTFaqcGwpyiTbzo=; b=Kge2OCCpAJlfS2mY5TQhs8VBrmgVktQquCIQS/WcuzK5w68i4eNFFPb/6lQ1YcJX16 I29lY6MMqkCSkOR33tEkX7cgLBhvWmkK0RtLvc/iri2HsJAVdmSSS2ueB1YQO8KFsIvm FzuFMt5Iq97VKR0sKlv6mYvdnIBIvZRhG6zo+VkakSjQIkEO01kP7t/E8Emh7jdzEhdj xL3hQRnf/9h1s6JvHGm3rR5wju2dIlEITEwrD13a8ZF+LQ8rIXeImNKdl0XoqpTzLFt6 q0Iad1lsL/ypgmFXtolLtr1GOnhTKA6JMYlsIRvUN5JW+vwbh1yUCJlEkloM9LBHFKIx H98g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787890770; x=1788495570; h=content-transfer-encoding:mime-version: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=GvQBCeK2pDC31wjSOrIf5IPUWWi4fTFaqcGwpyiTbzo=; b=l57Ciy+I0V73BzJmdFJd6sM2oQ6YLTbQDavROnVh7hM7/UCmkOcyPn3Jx241zH8/M7 zUV9q96coTIgPrRWgC0g1B4+S9/wV1M6q3zWLAO4jOaXdpdQ31wdJC/stTXgPWEU6UGD klRi5+HZb7X6s96mfdgCh321tnI1/rS4efT7/amxbthrQ1zKhOJJCea3SVuqp721eSVV FcgT9rQSRqs/TBKuarDY4ry7gIArLWEegF2LFklrUXZcXf/DiXIusT+g6diaMOyNyAji lOdGRCvMVNkQZUmhBsLdp7jzEIV1cHiG3oKiCAkkjoEgOv2JYAwbPTYCrh+S1xlnBDf3 su2g== X-Forwarded-Encrypted: i=1; AHgh+RpFNfnvdnNDXdkxXXkWE9qwg7+1OuYrPWqisQerZj41KFz9Y3Z4kiKow/X5LLxWaJ/LtoySL/U=@vger.kernel.org X-Gm-Message-State: AFuF++njCGQj+Sx4Mdre/CsFlcrqPZRdbyATjT9r2xYpZFR2Sawn+OeZ RGN+nUQCzqqR84EZH241e1FBG4vsZZ8rRwzUIffAOnLex46ndPu84W+S X-Gm-Gg: AR+sD12XNLkBLQ+ypSUW4dSnevbMwMl09VQ5TUw7hzEXjuTVmn/6BubCU9qTwZzKuMl 5QPsNwWpbXr2pLInfoR1jAlNp1gcNstugWc0vdRt3ssodfDsinQ0bYxEupJGhqHFWofehsfClZ3 Y0DhBPy9+9pgE2W/+pzd4HgX3Arvytyu3wzG/nQcFNm0NQIKgwbsfJS5nRs4kMcM+ADIDIgo7n1 5C/N0pEeThTdWQBa5l2NhP0vYjDXFblw6u+6kaUZwENgdW7pVfV+LCngOYUOxdqk+PwJ7erCpOa PQlQUCia53Edi4VFIMzMduskJh4tKfDw4w2X7+9zt+79BChJrTAMzoQd0KeJPW8rCGEDAWHHTpM 7KJwdRV2+lEGm1WKk05b3Yl+NTfrbHy+5nRliiXlN4QX3BsHztr1SbgNDhz5eFIgt3U5woqubWN fWeqxYlznlZQobdIezWwrN5xSriaZQVrIzjcYxbI1pwVr+Vw0PdhNf1R7D0SdlMuaBLTY= X-Received: by 2002:a53:c286:0:b0:667:e855:ecdb with SMTP id 956f58d0204a3-66e4c664521mr905723d50.3.1787890769747; Thu, 27 Aug 2026 21:19:29 -0700 (PDT) Received: from mac.lan ([136.55.173.105]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-66e4ed2a78bsm290978d50.20.2026.08.27.21.19.29 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 27 Aug 2026 21:19:29 -0700 (PDT) From: "Cen Zhang (Microsoft Security FORGE Labs)" To: cel@kernel.org, jlayton@kernel.org Cc: neil@brown.name, okorniev@redhat.com, Dai.Ngo@oracle.com, tom@talpey.com, bfields@fieldses.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, AutonomousCodeSecurity@microsoft.com, xmei5@asu.edu, tgopinath@linux.microsoft.com, kys@microsoft.com, blbllhy@gmail.com Subject: [PATCH] nfsd: hold cl_lock in client_has_state() Date: Fri, 28 Aug 2026 00:19:25 -0400 Message-ID: <20260828041925.36758-1-blbllhy@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit client_has_openowners() walks clp->cl_openowners and reads so_stateids without clp->cl_lock. nfs4_put_stateowner() unhashes that openowner under cl_lock and then frees it, so a concurrent EXCHANGE_ID with mismatched creds can use-after-free the nfs4_openowner. BUG: KASAN: slab-use-after-free in client_has_state+0x10a/0x140 fs/nfsd/nfs4state.c:3718 client_has_openowners() nfsd4_exchange_id nfsd4_proc_compound nfsd_dispatch svc_process Take clp->cl_lock while client_has_state() walks the openowner list. Fixes: 4eaea1342507 ("nfsd: improve client_has_state to check for unused openowners") Reported-by: Xiang Mei (Microsoft) Cc: AutonomousCodeSecurity@microsoft.com Cc: stable@vger.kernel.org Signed-off-by: Cen Zhang (Microsoft Security FORGE Labs) --- fs/nfsd/nfs4state.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 18e17232cf94..8d7a4c2eadbe 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -4216,12 +4216,18 @@ nfsd4_set_ex_flags(struct nfs4_client *new, struct nfsd4_exchange_id *clid) static bool client_has_openowners(struct nfs4_client *clp) { struct nfs4_openowner *oo; + bool found = false; + spin_lock(&clp->cl_lock); list_for_each_entry(oo, &clp->cl_openowners, oo_perclient) { - if (!list_empty(&oo->oo_owner.so_stateids)) - return true; + if (!list_empty(&oo->oo_owner.so_stateids)) { + found = true; + break; + } } - return false; + spin_unlock(&clp->cl_lock); + + return found; } static bool client_has_state(struct nfs4_client *clp) base-commit: 1b78070aaef63512688aebfbc82365ef9d6660f1 -- 2.55.0