From nobody Mon Jun 8 07:24:45 2026 Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) (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 84A7838F928 for ; Fri, 5 Jun 2026 04:30:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780633825; cv=none; b=Q7kIpS3Usz4fyB90VNnrvj2SsMAdCtlx7xR3GqwmquAonp88FO7d3IiUdjiNDwYedwEbZFP8H+dLJBRTWK8pRw2HmdcLgJK8I/zzlfGCnSXHrBFjlc0LcjF6hEW7EQDTzzVmLhcsr5pKJRHHLhoEH+S21wE+AwZ/Z7eENQTUEIE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780633825; c=relaxed/simple; bh=UZuK36PdajGvvnVo7gqEzruJ6LWrsxaDKanPqorC5Ls=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=tx86EaGjoin1IzyZI/XWoqVTsLLNP9Q+Wcmtjq49ejeMezPN/fOs5dBWzEfZo2zIHLWtsj9p+h8MOLQIuTu2nIc5gi+Pz41Euanfw0IiwScLvsWiwUqvoXWYGKgFEfqEHbYCgnAgGAEDuKMKGxxv5kyW/1DS/j9uz6RLPWLQfWQ= 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=O54OLNk9; arc=none smtp.client-ip=209.85.214.180 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="O54OLNk9" Received: by mail-pl1-f180.google.com with SMTP id d9443c01a7336-2bea7176c72so9797755ad.0 for ; Thu, 04 Jun 2026 21:30:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780633824; x=1781238624; 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; bh=6ujxSEDq4R8lp2y/Xo01gcDdYjorcuEfHYNTccxz27Y=; b=O54OLNk9UsgFHvqQGrwzateTaEvxTb74r4A+NcHV2LGqG3c6cw438mUUtNivfqzvMS zwKRzDd5JZac5s1OVymta5PjgguHEHMP6d01b2mNmsDH1ONJMA4jMrZoPMxcXvYCXKEN C/pAgeNzqWFkQajpfySWfIJqYMrCqEPFcNyHk8e55dl0WRaEvBKfkZEBag9IfjWPsu9O DmIO9hVcZqrRLN9iZdtxRhI3ti4v990FXEiKyveqcAcEqx6z17jusxgDdFNSBcUmPN6X xWg3jAya2ZVoNo6eFE/TIDvVVnZTQrQEBQudkdxZdDbUs6JOhewp59LPgsw54NW33eSy LhOg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780633824; x=1781238624; 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; bh=6ujxSEDq4R8lp2y/Xo01gcDdYjorcuEfHYNTccxz27Y=; b=U6dCb3IcJ6nsYDZ3caA5ehvC3sSLLbXU+THGLHS18qm7ZtgKb06tW9PLSe9JSXQY53 v19Lq7RtD23fJZproOBtlna3ILg0RA5vgdGDOn9KYeyXPtPLBXtCQanpnBryahHTX/zr cYNgIH1Ciooz6RDMgIGNtltvy67ZnOLK0+zYmmeCKi5JntyxpvueVDDmNZjmRO+/uC6D XJPGAoZDwSZ20nGzO464CPzoT3Iqp7IMYGldHHbel/RQm8HY0bLtZjL9MAnMDDOI/aYE m18DO87qVYO/cDft6FadlS8mneEmVNhT2Xzh7KfpuXacCmbCLPwvWcWTYYONgrMFwJ4C Rhiw== X-Forwarded-Encrypted: i=1; AFNElJ8/MkEksnzDTPnj+W74lJ0+TX3AtnYInnJEvgvc9+RnWSigtXvnX3efL4mJ9Z0BYxSmleYvGYBI0ZTw1HU=@vger.kernel.org X-Gm-Message-State: AOJu0YyychF039n8+Gyzk6fPWYNPTjQxQV02B5UmKR2NDum8ZlBsUQSZ +dJiX8nqHmyvnRx1jFeIxL8HZQ0vLWYAXzwwsrS9lsYS0GIFlJY4/tZ2YllSJKkeGbY= X-Gm-Gg: Acq92OH4JVNzSohlKuH3PXjIC0rEwGMsOb9R60QJA3Ttf0c9HSnMNVAX/MxCoNp035G Xh4ecdTjZNcnBZ2nXCUZviKUp2J5jKUhZt8c4VgOHclqBo7d8fj9p2jnNYeEHo16NbMiWB/hQ71 7tgo4WjzKi4Pq4JQ8i/fcswff3uoFfZEABD2OmeQOaykYRT7Yv+RBqHvSQVnZCbwWBfMAfTEHKz eRYL+pQ6PFD6wQ4fcmVLBDrUJZOE4oMpNZ8ZsElh3bqrP/1Ybl3Hva7gLUOv/CMJWMrwwBDlGVE 0QvLHwgWRHGPYyeMmCz2usCW4Q4McAHa3KdB1jpzBkHqAm/5PcXfjtnHciPHGBdWsWZiTcp2S0m cLsYgtnhgyXZixRzXYeLxeVjylREPsXjeo4tlg+f5MR149E1V+gEVW6pWDmS1aRPRtFodBPIOMD EKr04eRJ7sR63T5Wjkb+r1wtI1pr8lqNS3iFNMEYZIiA== X-Received: by 2002:a17:902:d58f:b0:2bf:195d:21d2 with SMTP id d9443c01a7336-2c1e7e44e91mr18339595ad.16.1780633823560; Thu, 04 Jun 2026 21:30:23 -0700 (PDT) Received: from lgs.. ([101.76.249.46]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2c1664ad138sm78825415ad.82.2026.06.04.21.30.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Jun 2026 21:30:23 -0700 (PDT) From: Guangshuo Li To: Namjae Jeon , Steve French , Sergey Senozhatsky , Tom Talpey , Hyunchul Lee , Ronnie Sahlberg , linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Guangshuo Li Subject: [PATCH] ksmbd: fix use-after-free in same_client_has_lease() Date: Fri, 5 Jun 2026 12:30:16 +0800 Message-ID: <20260605043016.1440866-1-lgs201920130244@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" same_client_has_lease() returns an opinfo pointer from ci->m_op_list after dropping ci->m_lock without taking a reference. smb_grant_oplock() then dereferences that pointer in copy_lease() and when checking breaking_cnt. A concurrent close can remove the old lease from ci->m_op_list and drop the last reference before the caller uses the returned pointer, leading to a use-after-free. Take a reference when same_client_has_lease() selects an existing lease, drop any previous match while scanning, and release the returned reference in smb_grant_oplock() after copying the lease state. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Guangshuo Li --- fs/smb/server/oplock.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c index 0f5c18520eff..5e717aa03446 100644 --- a/fs/smb/server/oplock.c +++ b/fs/smb/server/oplock.c @@ -528,7 +528,12 @@ static struct oplock_info *same_client_has_lease(struc= t ksmbd_inode *ci, =20 ret =3D compare_guid_key(opinfo, client_guid, lctx->lease_key); if (ret) { + if (!atomic_inc_not_zero(&opinfo->refcount)) + continue; + if (m_opinfo) + opinfo_put(m_opinfo); m_opinfo =3D opinfo; + /* skip upgrading lease about breaking lease */ if (atomic_read(&opinfo->breaking_cnt)) continue; @@ -1237,6 +1242,7 @@ int smb_grant_oplock(struct ksmbd_work *work, int req= _op_level, u64 pid, if (atomic_read(&m_opinfo->breaking_cnt)) opinfo->o_lease->flags =3D SMB2_LEASE_FLAG_BREAK_IN_PROGRESS_LE; + opinfo_put(m_opinfo); goto out; } } --=20 2.43.0