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 4BBF03E022B for ; Mon, 30 Mar 2026 19:11:11 +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=1774897871; cv=none; b=Bvz/knruoTehA7sd9GpEgu2eM8lHdGkjyPVdhTLGdUiSqDPfa5woNzJZqmOaJJOYfyalXPwj6HuCGSOEDrN+XXJzU8t+y9i/UP2cezHMFCs/8AlvDrCkmRfPd0rarb6CXibdbiC1oksOn1tofbM58VDG77o/GBeXML0MBStzdl0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774897871; c=relaxed/simple; bh=AX8pz97sGe9XE5xJiclNo/ugf4zZKoap+D78iWsjAsE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qcG5Z8ZyEX5N2vZtgpqbdsjifTTZBLi2By2JSNWYJS+5PMUHMS8aG2bMmkjKcRpYNQPEu7oxh0qEtTXyAQXt8jNMRa0IOQdIl0SsJl7fxKRx/IG+JVn2aWB7evONNRCEyVGG5y1shxccwJEWK4KsCFCPdLORQrjGagSApSdUsiM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uu+Z6mbl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uu+Z6mbl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F7C2C2BC9E; Mon, 30 Mar 2026 19:11:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774897871; bh=AX8pz97sGe9XE5xJiclNo/ugf4zZKoap+D78iWsjAsE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uu+Z6mblvP4kjMFAJQ1G5oz56VlBACV9L+fI21haoBhTdhUNNIwC4a6zP3RH1DINt Af8WRkwfVc8yb2b1wpxyMedSw8apV1yqKCZFGlJIdKGxzlnW4TRdOBpz4Wc9xIjtMl Va1dJBLNsObb20D4iodeTqLrpSh5J66BPQSm3DI7Ww8Bpe0bf83gHzj+eVxa0nlvb1 YSuXl7wkPeUj/4Dowzph3HhmJRvnvDE5IVQ+3DUn/8q5EQxp6iz51Tdv4E/mDox+uy 7EdABE0s9FWRJGEnbPWvSow97v7aCiiFaCVCM9oO9bVeAZBpHkfcS2YfFyZvfPTQ+w BUWkaZct4Qiww== From: Sasha Levin To: stable@vger.kernel.org Cc: Werner Kasselman , ChenXiaoSong , Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 6.6.y] ksmbd: fix memory leaks and NULL deref in smb2_lock() Date: Mon, 30 Mar 2026 15:11:09 -0400 Message-ID: <20260330191109.1038495-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026032951-delivery-lilly-753c@gregkh> References: <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-Transfer-Encoding: 8bit From: Werner Kasselman [ Upstream commit 309b44ed684496ed3f9c5715d10b899338623512 ] 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 [ adapted rlock->c.flc_type to rlock->fl_type ] Signed-off-by: Sasha Levin --- fs/smb/server/smb2pdu.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c index bdd2214c79f98..ca59badb42a73 100644 --- a/fs/smb/server/smb2pdu.c +++ b/fs/smb/server/smb2pdu.c @@ -7515,14 +7515,15 @@ 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; @@ -7591,6 +7592,9 @@ 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; } } @@ -7621,13 +7625,17 @@ int smb2_lock(struct ksmbd_work *work) struct file_lock *rlock = NULL; rlock = smb_flock_init(filp); - rlock->fl_type = F_UNLCK; - rlock->fl_start = smb_lock->start; - rlock->fl_end = smb_lock->end; + if (rlock) { + rlock->fl_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); @@ -7637,7 +7645,8 @@ 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: -- 2.53.0