The patch below does not apply to the 5.15-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 stable@vger.kernel.org.

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-5.15.y git checkout FETCH_HEAD git cherry-pick -x 75ac9a3dd65f7eab4d12b0a0f744234b5300a491 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023100806-buckwheat-epiphany-17f3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

75ac9a3dd65f ("ksmbd: fix race condition from parallel smb2 lock requests") 38c8a9a52082 ("smb: move client and server files to common directory fs/smb") 3a9b557f44ea ("ksmbd: delete asynchronous work from list") d3ca9f7aeba7 ("ksmbd: fix possible memory leak in smb2_lock()") f8d6e7442aa7 ("ksmbd: fix typo, syncronous->synchronous") abdb1742a312 ("cifs: get rid of mount options string parsing") 9fd29a5bae6e ("cifs: use fs_context for automounts") 5dd8ce24667a ("cifs: missing directory in MAINTAINERS file") 332019e23a51 ("Merge tag '5.20-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 75ac9a3dd65f7eab4d12b0a0f744234b5300a491 Mon Sep 17 00:00:00 2001 From: Namjae Jeon linkinjeon@kernel.org Date: Wed, 4 Oct 2023 18:31:03 +0900 Subject: [PATCH] ksmbd: fix race condition from parallel smb2 lock requests

There is a race condition issue between parallel smb2 lock request.

Time + Thread A | Thread A smb2_lock | smb2_lock | insert smb_lock to lock_list | spin_unlock(&work->conn->llist_lock) | | | spin_lock(&conn->llist_lock); | kfree(cmp_lock); | // UAF! | list_add(&smb_lock->llist, &rollback_list) +

This patch swaps the line for adding the smb lock to the rollback list and adding the lock list of connection to fix the race issue.

Reported-by: luosili rootlab@huawei.com Signed-off-by: Namjae Jeon linkinjeon@kernel.org Signed-off-by: Steve French stfrench@microsoft.com

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index e774c9855f7f..fd6f05786ac2 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7038,10 +7038,6 @@ int smb2_lock(struct ksmbd_work *work)

ksmbd_debug(SMB, "would have to wait for getting lock\n"); - spin_lock(&work->conn->llist_lock); - list_add_tail(&smb_lock->clist, - &work->conn->lock_list); - spin_unlock(&work->conn->llist_lock); list_add(&smb_lock->llist, &rollback_list);

argv = kmalloc(sizeof(void *), GFP_KERNEL); @@ -7072,9 +7068,6 @@ int smb2_lock(struct ksmbd_work *work)

if (work->state != KSMBD_WORK_ACTIVE) { list_del(&smb_lock->llist); - spin_lock(&work->conn->llist_lock); - list_del(&smb_lock->clist); - spin_unlock(&work->conn->llist_lock); locks_free_lock(flock);

if (work->state == KSMBD_WORK_CANCELLED) { @@ -7094,19 +7087,16 @@ int smb2_lock(struct ksmbd_work *work) }

list_del(&smb_lock->llist); - spin_lock(&work->conn->llist_lock); - list_del(&smb_lock->clist); - spin_unlock(&work->conn->llist_lock); release_async_work(work); goto retry; } else if (!rc) { + list_add(&smb_lock->llist, &rollback_list); spin_lock(&work->conn->llist_lock); list_add_tail(&smb_lock->clist, &work->conn->lock_list); list_add_tail(&smb_lock->flist, &fp->lock_list); spin_unlock(&work->conn->llist_lock); - list_add(&smb_lock->llist, &rollback_list); ksmbd_debug(SMB, "successful in taking lock\n"); } else { goto out;