From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f41.google.com (mail-dl1-f41.google.com [74.125.82.41]) (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 1EBFA3BC69C for ; Thu, 2 Apr 2026 08:39:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775119163; cv=none; b=cltu+CWyD0JFe86MEjz6XJcVNkA8jr1PTs+VVEV+DlAInp/6vqIRjBFNZp5mT2jSM2tloBoULJW7f5kchGCWve/GhyV9F5tktFpu3JDBQhdz6qv27hZP6vYBvlaRNpk7D1HqTfxOP6hKqkEjAAl9ki9PKKX7IR2yYeOwpDqjgOA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775119163; c=relaxed/simple; bh=cwiMGb+QvJPPbyOUbTGVlCDSVPPTs9vIaN+NXNJAVn8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=hKpTHaLnaFSWazZEkN6uQ/oPoEMvi4oCUB7MoP7ug3FcV6X89FxukkSF/PGLrmqBc76DqliMYyh85cpU10UCfnbk35PqmP0OaLOYzn5hjhgq3ncOIYII06iFxdSmvl6BR0U0BQ4uwub92QJMJVUT57EIvUaQayhD/SToWC/dcq8= 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=K/FgGiS+; arc=none smtp.client-ip=74.125.82.41 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="K/FgGiS+" Received: by mail-dl1-f41.google.com with SMTP id a92af1059eb24-128ebee22caso1100596c88.0 for ; Thu, 02 Apr 2026 01:39:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1775119161; x=1775723961; 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=7eITVDgwa5tEdf7gs96GHN8iyQzNKskoC8moYtKLcKc=; b=K/FgGiS+3PI2cFIE2N+jYPaP3BbsprXkLelxACmeih+ZJPGr6NWju/f1916TjbFFkf hZe/o0+7Mi9Nh8LR39DkgNxuql0TvOgBtyNcn1eupfqiLol1ElVgjyYZR+Z8PlS4FUBE 7jRTE9z5OvIAyBmxLHB9M+3u5Q/wfYaqkcEvbBY70NJPMbUDyALNBmj/2rjWlr9+XU9s oEZt77sdmJCjDlY3137MMUZLABPhV1KibPuvqW/3dyFG6aQuDsPk7Ocbx2P6e6QcOYNw d+JugzOrlkOzt5+fw89gpYcKlXSuZDxFsSJX/CTvk7oDCSVYAXzPlMbzdiN6cfqaiK3N 292g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775119161; x=1775723961; 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=7eITVDgwa5tEdf7gs96GHN8iyQzNKskoC8moYtKLcKc=; b=G+p4zaOhLG1sVvzHy8NxAj/Jjj2ebCoufWGAckn8dnRSDKy7tJ7n3bANsNMR1dyEnf kgiWqu2wR9UjDKhBwk8xT0sMS9BGPKeg2e+wg8EYiagpPAebNnTuf8QdyZv9B0yx5b+Y ZsHzbYIteXuuplqiqh11TD20Z5HryT/MIWA97fTYa7y9fe0gm7+kkNddmDkY1tsCdlms OwW8z3eXb+Qv2LmwZwy6bkc0ZGqekQ1Ab34EDu+xiSJauDozSJ2CiAIQXwXEznPh81cZ N5v7wFLSEPwDzzAq5l+Oby/hKDM7/dq/y901LKqgHFndA8sZ7m1vJpeuF6jqfmgnFg6t AWig== X-Forwarded-Encrypted: i=1; AJvYcCWf2schdICC9itmVwUkXKo9AdKH7Pd8NESlSHrCFuqaxN1LL08mpO6waGM2F5MB8r1jLHBjlb8=@vger.kernel.org X-Gm-Message-State: AOJu0Yw2ZwKauxM8wMMFct7pAYw6mNNx//6cZItdV6W0eS/eDTknFWDi RImXqtRecErgPNZYKlfgaam6YuuuOb6CDFH/XYVruR84l7UW2Afep5fG X-Gm-Gg: ATEYQzw9gewE1rA8W3VJd22z9ZyM4WxM0McuUZeuS1XFkZdySwe/SWn1VP0etgu34fU lWsF2TfCInjgexqJ/ZxygS1OKzrIDg8Jk0BHI4Z1uQcJ1xivb1A0kevmiGek/pG+FSWzV5nZhEo DG1ckzOziDfnbIgL+SLQ1iLH4qGm5b+AbA9AAoYQFklSRQtfaynPXr4LFd8deOjnvHala8uWL78 /C/sLPmZg8aTrq6MNA+ZAj2VR0LqFILYKxF/0lYnFVaqDfkJm9zKAC9IYvS9K6NjKCoQhcBj9l1 PNX3TvWAo/RFPk1lfgzgjujnwoqk1zmgGVDakEdyWFRi+By8SsMfoKIc8VL+/UdyiEuOzszDK21 nm6QK7yrwZBrP7fOkIM1Wqg+WvYvc1WKSgES8mK4TedrKlCA5qDIUIzL+p+Dp/+B3J9aGpPYEre vgwk5v1prmg7txiA5+/1yKGBClrWAGiWyvpGQ4s6i6nPfw75xWnTRp3cZ8CA== X-Received: by 2002:a05:7022:f8e:b0:119:e56b:957c with SMTP id a92af1059eb24-12bee613f8cmr1450943c88.1.1775119161057; Thu, 02 Apr 2026 01:39:21 -0700 (PDT) Received: from ubuntu22-base.lan (104.194.93.216.16clouds.com. [104.194.93.216]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-12bedd4e4e3sm1716646c88.1.2026.04.02.01.39.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Apr 2026 01:39:20 -0700 (PDT) From: munan Huang To: linkinjeon@kernel.org, smfrench@gmail.com, senozhatsky@chromium.org, tom@talpey.com Cc: linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, munan Huang , stable@vger.kernel.org Subject: [PATCH] ksmbd: fix use-after-free in __ksmbd_close_fd() lock cleanup Date: Thu, 2 Apr 2026 08:39:12 +0000 Message-Id: <20260402083912.457676-1-munanevil@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In __ksmbd_close_fd(), when cleaning up byte-range locks on a durable file handle closed by the scavenger, the lock cleanup loop unconditionally dereferences fp->conn->llist_lock to remove each lock from the connection's list: list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) { spin_lock(&fp->conn->llist_lock); list_del(&smb_lock->clist); spin_unlock(&fp->conn->llist_lock); } However, when a client disconnects without SMB2 LOGOFF, ksmbd preserves durable file handles via session_fd_check(), which sets fp->conn to NULL and arms the durable scavenger timeout, but does not detach the byte-range locks from the dying connection's lock list. When the scavenger timeout expires, ksmbd_durable_scavenger() calls __ksmbd_close_fd(NULL, fp). At this point fp->conn is NULL and the original connection object has already been freed by ksmbd_conn_free(), so it would cause a use-after-free or NULL pointer dereference. Fix by checking fp->conn for NULL before accessing fp->conn->llist_lock in the lock cleanup loop. Fixes: c8efcc786146 ("ksmbd: add support for durable handles v1/v2") Cc: stable@vger.kernel.org Signed-off-by: munan Huang --- fs/smb/server/vfs_cache.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/smb/server/vfs_cache.c b/fs/smb/server/vfs_cache.c index 168f2dd7e200..772a84d95fe3 100644 --- a/fs/smb/server/vfs_cache.c +++ b/fs/smb/server/vfs_cache.c @@ -463,9 +463,11 @@ static void __ksmbd_close_fd(struct ksmbd_file_table *ft, struct ksmbd_file *fp) * there are not accesses to fp->lock_list. */ list_for_each_entry_safe(smb_lock, tmp_lock, &fp->lock_list, flist) { - spin_lock(&fp->conn->llist_lock); - list_del(&smb_lock->clist); - spin_unlock(&fp->conn->llist_lock); + if (fp->conn) { + spin_lock(&fp->conn->llist_lock); + list_del(&smb_lock->clist); + spin_unlock(&fp->conn->llist_lock); + } list_del(&smb_lock->flist); locks_free_lock(smb_lock->fl); -- 2.34.1