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 8D6CB2E11A6; Tue, 31 Mar 2026 17:04:27 +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=1774976667; cv=none; b=EK7SNGQBr7QpACX5uogpRQlTx9hbZU2wm9OFdVyv/CY3NFpZCZ8ANOl2GjQ24FR52QaBWklM/WXsy7KnRG1SI+IJJHgHzaL0QrqHVutuDqWPlGQwt8BIAqEjgTdStnRZfveyodXzlwU0O2dvGr2i3KrHIjDIO6XnQ2EYX1tTx2Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774976667; c=relaxed/simple; bh=dza7VChuPQpyoSVaPnU/tsbnjiXEb9TnyYuNcl7h07U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AKX35oKRsH884Hp9yC4Ombhi5SgVHJ55EuA2jm76jusjzzW1lH+4dLpvmEzhxVrSQ+aA8+IT3lXgiVsLeOX/Z+1JX7V8R7Ra7KRSFQg3vv0T9TPIrxYFOvRaoSw022twimKmqvKCj+BYObqpRppdgLNpgH198fhQK3ymj846WDU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0b4W0ryF; 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="0b4W0ryF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 238F5C19423; Tue, 31 Mar 2026 17:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774976667; bh=dza7VChuPQpyoSVaPnU/tsbnjiXEb9TnyYuNcl7h07U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0b4W0ryFzr9o8s1KOFOP2EaNbBd7zmOOHVUzROuvGl9Oa7DaMBYkvR2ug4yYh6gNV 9SVODk3QmgFjOw00Gdsut9Z4AK81qJ0YrXdUwz5dfekj3va7Erc5y8P0givIYhQS8Q 0fvYo7CapaZ00zcJwACDZC8ZDKmi6nCxYgCg5/Zo= 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 6.18 182/309] ksmbd: fix memory leaks and NULL deref in smb2_lock() Date: Tue, 31 Mar 2026 18:21:25 +0200 Message-ID: <20260331161800.164108475@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161753.468533260@linuxfoundation.org> References: <20260331161753.468533260@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 6.18-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 @@ -7602,14 +7602,15 @@ 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; @@ -7678,6 +7679,9 @@ 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; } } @@ -7708,13 +7712,17 @@ 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); @@ -7724,7 +7732,8 @@ 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: