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 D02D322D4DC for ; Sun, 29 Mar 2026 07:20:54 +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=1774768854; cv=none; b=BLTVH9xRleh80TUHWRHZ9tydDD3EDaR7KbUHRwmIbirWnf/ONk+E5aN5S6yf0NvCLQY+nyWeVxLftnzzPXjftxnUPUDbtMYaWn1yNEZJNb1vLRrna3lILWDk+337FM7GzRJLILvh59eZj2a7Lm/tqKyK88ONJv80y+PiebZvM3E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774768854; c=relaxed/simple; bh=SlCv84Pvn0bIR1xwVf15njNRIWt426XzGDswgiQB9WU=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=oEPYGOzMNt5NEwv/k0lADV0iHytzHYMFN5LzDd5s9Vo0krKSG8Bp7OLUi9wvvhBPIaaA+Q3QbQkn4GBHoF5bHCBZvZoYCRdWgRVZW1gEpexnMj1ZFoxjjYr7B0r0Y74rw7Ykwl9WQtFxUCz7Y90Mp1DXHibCDt6S/y8SOGEAUvQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=XHzF43T1; 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="XHzF43T1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3984EC116C6; Sun, 29 Mar 2026 07:20:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774768854; bh=SlCv84Pvn0bIR1xwVf15njNRIWt426XzGDswgiQB9WU=; h=Subject:To:Cc:From:Date:From; b=XHzF43T1tkraG42Vj9bv6ObyN0Vt4YJp+9jKdzCdlIHnv0OV+mvYck8e4O/Psvxer EK5A2fPFQy1xbE90p7iRy+EDn/bB/AKRTEOj867w+vwlBfWWguZ06hbHE/C0uWjl8l YB5hVw+coRiSGqOsKPfcMkeqjglLIVpsGKsnE1G8= Subject: FAILED: patch "[PATCH] ksmbd: fix memory leaks and NULL deref in smb2_lock()" failed to apply to 6.6-stable tree To: werner@verivus.com,chenxiaosong@kylinos.cn,linkinjeon@kernel.org,stfrench@microsoft.com Cc: From: Date: Sun, 29 Mar 2026 09:20:51 +0200 Message-ID: <2026032951-delivery-lilly-753c@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 309b44ed684496ed3f9c5715d10b899338623512 # git commit -s git send-email --to '' --in-reply-to '2026032951-delivery-lilly-753c@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 309b44ed684496ed3f9c5715d10b899338623512 Mon Sep 17 00:00:00 2001 From: Werner Kasselman Date: Tue, 17 Mar 2026 07:55:37 +0000 Subject: [PATCH] ksmbd: fix memory leaks and NULL deref in smb2_lock() 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 diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index 8fa780e8efd0..24f8d58493d0 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7592,14 +7592,15 @@ int smb2_lock(struct ksmbd_work *work) 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; @@ -7668,6 +7669,9 @@ int smb2_lock(struct ksmbd_work *work) 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; } } @@ -7698,13 +7702,17 @@ int smb2_lock(struct ksmbd_work *work) 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; + 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); + 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); @@ -7714,7 +7722,8 @@ int smb2_lock(struct ksmbd_work *work) 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: