CVE-2022-49741

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

fbdev: smscufx: fix error handling code in ufx_usb_probe

The current error handling code in ufx_usb_probe have many unmatching issues, e.g., missing ufx_free_usb_list, destroy_modedb label should only include framebuffer_release, fb_dealloc_cmap only matches fb_alloc_cmap.

My local syzkaller reports a memory leak bug:

memory leak in ufx_usb_probe

BUG: memory leak unreferenced object 0xffff88802f879580 (size 128): comm “kworker/0:7”, pid 17416, jiffies 4295067474 (age 46.710s) hex dump (first 32 bytes): 80 21 7c 2e 80 88 ff ff 18 d0 d0 0c 80 88 ff ff .!|…………. 00 d0 d0 0c 80 88 ff ff e0 ff ff ff 0f 00 00 00 ……………. backtrace: [] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045 [] kmalloc include/linux/slab.h:553 [inline] [] kzalloc include/linux/slab.h:689 [inline] [] ufx_alloc_urb_list drivers/video/fbdev/smscufx.c:1873 [inline] [] ufx_usb_probe+0x11c/0x15a0 drivers/video/fbdev/smscufx.c:1655 [] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396 [] call_driver_probe drivers/base/dd.c:560 [inline] [] really_probe+0x12d/0x390 drivers/base/dd.c:639 [] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778 [] driver_probe_device+0x2a/0x120 drivers/base/dd.c:808 [] __device_attach_driver+0xf7/0x150 drivers/base/dd.c:936 [] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427 [] __device_attach+0x105/0x2d0 drivers/base/dd.c:1008 [] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487 [] device_add+0x642/0xdc0 drivers/base/core.c:3517 [] usb_set_configuration+0x8ef/0xb80 drivers/usb/core/message.c:2170 [] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238 [] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293 [] call_driver_probe drivers/base/dd.c:560 [inline] [] really_probe+0x12d/0x390 drivers/base/dd.c:639 [] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778

Fix this bug by rewriting the error handling code in ufx_usb_probe.

Affected product:

AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 6 ELS , CloudLinux 7 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

kernel @ 2.6.32 (+15 more)

In the Linux kernel, the following vulnerability has been resolved:

fbdev: smscufx: fix error handling code in ufx_usb_probe

The current error handling code in ufx_usb_probe have many unmatching issues, e.g., missing ufx_free_usb_list, destroy_modedb label should only include framebuffer_release, fb_dealloc_cmap only matches fb_alloc_cmap.

My local syzkaller reports a memory leak bug:

memory leak in ufx_usb_probe

BUG: memory leak unreferenced object 0xffff88802f879580 (size 128): comm “kworker/0:7”, pid 17416, jiffies 4295067474 (age 46.710s) hex dump (first 32 bytes): 80 21 7c 2e 80 88 ff ff 18 d0 d0 0c 80 88 ff ff .!|…………. 00 d0 d0 0c 80 88 ff ff e0 ff ff ff 0f 00 00 00 ……………. backtrace: [] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045 [] kmalloc include/linux/slab.h:553 [inline] [] kzalloc include/linux/slab.h:689 [inline] [] ufx_alloc_urb_list drivers/video/fbdev/smscufx.c:1873 [inline] [] ufx_usb_probe+0x11c/0x15a0 drivers/video/fbdev/smscufx.c:1655 [] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396 [] call_driver_probe drivers/base/dd.c:560 [inline] [] really_probe+0x12d/0x390 drivers/base/dd.c:639 [] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778 [] driver_probe_device+0x2a/0x120 drivers/base/dd.c:808 [] __device_attach_driver+0xf7/0x150 drivers/base/dd.c:936 [] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427 [] __device_attach+0x105/0x2d0 drivers/base/dd.c:1008 [] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487 [] device_add+0x642/0xdc0 drivers/base/core.c:3517 [] usb_set_configuration+0x8ef/0xb80 drivers/usb/core/message.c:2170 [] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238 [] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293 [] call_driver_probe drivers/base/dd.c:560 [inline] [] really_probe+0x12d/0x390 drivers/base/dd.c:639 [] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778

Fix this bug by rewriting the error handling code in ufx_usb_probe.