From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EBCB7426D2F; Tue, 31 Mar 2026 16:52:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774975972; cv=none; b=dHbEMhul312yTndVikNiZx4dvGbo6uCMOW8eqIIcA1DWtTbAV4M4jPy8B9WLCExVz4gXsWNfemeg93DVs/iKEUR1OzQNl0IY+Tb9RmUBnGzEaI7zESh49KCuabsYC/l2w5plpD+ADUDwHK17ql6GP3MRQ0yY+tfn0KT78RV44lw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774975972; c=relaxed/simple; bh=X9tddw6sBuzO9cwSVVPZvclPNJkBCLgIIbEAzdSu+sI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I5Xxf5Y9zwHxGEuv5RrPjynmsLBiZmauMsOxwutMTnrU8hCFqtJYmAHDAG45YSzb2yHuvReuWU+ASvhU3se6ELkgmhHwU6iAIMePoc2HLFrfAMRs9zBVxxPdFaLugKrsGhmbm73KUlKoWDc1f/4KzA17pCbymqeltINIXpS2Bxg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bdZu6cs1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bdZu6cs1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31D05C19423; Tue, 31 Mar 2026 16:52:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774975971; bh=X9tddw6sBuzO9cwSVVPZvclPNJkBCLgIIbEAzdSu+sI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bdZu6cs1iVM9YK6GiRfdGKEuK6NHg2UXhgQ0WcnBbPoXBS/ALdD29SBmGeWRHwPV3 CzHg5zGTtQUQA33uzEv4H5X7whVin/eB3Q9StzmyAHSc8vFN1qn75zB+1Pn1f+IlIB 91hjE24/05hqyvVSnkO8odmSgvsIe1G9z9NfmrmI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, ChenXiaoSong , Werner Kasselman , Namjae Jeon , Steve French Subject: [PATCH 6.12 140/244] ksmbd: fix memory leaks and NULL deref in smb2_lock() Date: Tue, 31 Mar 2026 18:21:30 +0200 Message-ID: <20260331161746.820612016@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161741.651718120@linuxfoundation.org> References: <20260331161741.651718120@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Werner Kasselman commit 309b44ed684496ed3f9c5715d10b899338623512 upstream. smb2_lock() has three error handling issues after list_del() detaches smb_lock from lock_list at no_check_cl: 1) If vfs_lock_file() returns an unexpected error in the non-UNLOCK path, goto out leaks smb_lock and its flock because the out: handler only iterates lock_list and rollback_list, neither of which contains the detached smb_lock. 2) If vfs_lock_file() returns -ENOENT in the UNLOCK path, goto out leaks smb_lock and flock for the same reason. The error code returned to the dispatcher is also stale. 3) In the rollback path, smb_flock_init() can return NULL on allocation failure. The result is dereferenced unconditionally, causing a kernel NULL pointer dereference. Add a NULL check to prevent the crash and clean up the bookkeeping; the VFS lock itself cannot be rolled back without the allocation and will be released at file or connection teardown. Fix cases 1 and 2 by hoisting the locks_free_lock()/kfree() to before the if(!rc) check in the UNLOCK branch so all exit paths share one free site, and by freeing smb_lock and flock before goto out in the non-UNLOCK branch. Propagate the correct error code in both cases. Fix case 3 by wrapping the VFS unlock in an if(rlock) guard and adding a NULL check for locks_free_lock(rlock) in the shared cleanup. Found via call-graph analysis using sqry. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Cc: stable@vger.kernel.org Suggested-by: ChenXiaoSong Signed-off-by: Werner Kasselman Reviewed-by: ChenXiaoSong Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/server/smb2pdu.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7552,14 +7552,15 @@ retry: rc = vfs_lock_file(filp, smb_lock->cmd, flock, NULL); skip: if (smb_lock->flags & SMB2_LOCKFLAG_UNLOCK) { + locks_free_lock(flock); + kfree(smb_lock); if (!rc) { ksmbd_debug(SMB, "File unlocked\n"); } else if (rc == -ENOENT) { rsp->hdr.Status = STATUS_NOT_LOCKED; + err = rc; goto out; } - locks_free_lock(flock); - kfree(smb_lock); } else { if (rc == FILE_LOCK_DEFERRED) { void **argv; @@ -7628,6 +7629,9 @@ skip: spin_unlock(&work->conn->llist_lock); ksmbd_debug(SMB, "successful in taking lock\n"); } else { + locks_free_lock(flock); + kfree(smb_lock); + err = rc; goto out; } } @@ -7658,13 +7662,17 @@ out: struct file_lock *rlock = NULL; rlock = smb_flock_init(filp); - rlock->c.flc_type = F_UNLCK; - rlock->fl_start = smb_lock->start; - rlock->fl_end = smb_lock->end; - - rc = vfs_lock_file(filp, F_SETLK, rlock, NULL); - if (rc) - pr_err("rollback unlock fail : %d\n", rc); + if (rlock) { + rlock->c.flc_type = F_UNLCK; + rlock->fl_start = smb_lock->start; + rlock->fl_end = smb_lock->end; + + rc = vfs_lock_file(filp, F_SETLK, rlock, NULL); + if (rc) + pr_err("rollback unlock fail : %d\n", rc); + } else { + pr_err("rollback unlock alloc failed\n"); + } list_del(&smb_lock->llist); spin_lock(&work->conn->llist_lock); @@ -7674,7 +7682,8 @@ out: spin_unlock(&work->conn->llist_lock); locks_free_lock(smb_lock->fl); - locks_free_lock(rlock); + if (rlock) + locks_free_lock(rlock); kfree(smb_lock); } out2: