Patch "vduse: avoid empty string for dev name" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    vduse: avoid empty string for dev name

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     vduse-avoid-empty-string-for-dev-name.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit f4199fc856593832e2f4720b325481dde2fff318
Author: Sheng Zhao <sheng.zhao@xxxxxxxxxxxxx>
Date:   Tue May 30 11:36:26 2023 +0800

    vduse: avoid empty string for dev name
    
    [ Upstream commit a90e8608eb0ed93d31ac0feb055f77ce59512542 ]
    
    Syzkaller hits a kernel WARN when the first character of the dev name
    provided is NULL. Solution is to add a NULL check before calling
    cdev_device_add() in vduse_create_dev().
    
    kobject: (0000000072042169): attempted to be registered with empty name!
    WARNING: CPU: 0 PID: 112695 at lib/kobject.c:236
    Call Trace:
     kobject_add_varg linux/src/lib/kobject.c:390 [inline]
     kobject_add+0xf6/0x150 linux/src/lib/kobject.c:442
     device_add+0x28f/0xc20 linux/src/drivers/base/core.c:2167
     cdev_device_add+0x83/0xc0 linux/src/fs/char_dev.c:546
     vduse_create_dev linux/src/drivers/vdpa/vdpa_user/vduse_dev.c:2254 [inline]
     vduse_ioctl+0x7b5/0xf30 linux/src/drivers/vdpa/vdpa_user/vduse_dev.c:2316
     vfs_ioctl linux/src/fs/ioctl.c:47 [inline]
     file_ioctl linux/src/fs/ioctl.c:510 [inline]
     do_vfs_ioctl+0x14b/0xa80 linux/src/fs/ioctl.c:697
     ksys_ioctl+0x7c/0xa0 linux/src/fs/ioctl.c:714
     __do_sys_ioctl linux/src/fs/ioctl.c:721 [inline]
     __se_sys_ioctl linux/src/fs/ioctl.c:719 [inline]
     __x64_sys_ioctl+0x42/0x50 linux/src/fs/ioctl.c:719
     do_syscall_64+0x94/0x330 linux/src/arch/x86/entry/common.c:291
     entry_SYSCALL_64_after_hwframe+0x44/0xa9
    
    Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
    Cc: "Xie Yongji" <xieyongji@xxxxxxxxxxxxx>
    Reported-by: Xianjun Zeng <zengxianjun@xxxxxxxxxxxxx>
    Signed-off-by: Sheng Zhao <sheng.zhao@xxxxxxxxxxxxx>
    Message-Id: <20230530033626.1266794-1-sheng.zhao@xxxxxxxxxxxxx>
    Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
    Reviewed-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
    Cc: "Michael S. Tsirkin"<mst@xxxxxxxxxx>, "Jason Wang"<jasowang@xxxxxxxxxx>,
    Reviewed-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 31017ebc4d7c7..72f924ec4658d 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1443,6 +1443,9 @@ static bool vduse_validate_config(struct vduse_dev_config *config)
 	if (config->vq_num > 0xffff)
 		return false;
 
+	if (!config->name[0])
+		return false;
+
 	if (!device_is_allowed(config->device_id))
 		return false;