CVE-2022-49741

Summary

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: [<ffffffff814c99a0>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1045 [<ffffffff824d219c>] kmalloc include/linux/slab.h:553 [inline] [<ffffffff824d219c>] kzalloc include/linux/slab.h:689 [inline] [<ffffffff824d219c>] ufx_alloc_urb_list drivers/video/fbdev/smscufx.c:1873 [inline] [<ffffffff824d219c>] ufx_usb_probe+0x11c/0x15a0 drivers/video/fbdev/smscufx.c:1655 [<ffffffff82d17927>] usb_probe_interface+0x177/0x370 drivers/usb/core/driver.c:396 [<ffffffff82712f0d>] call_driver_probe drivers/base/dd.c:560 [inline] [<ffffffff82712f0d>] really_probe+0x12d/0x390 drivers/base/dd.c:639 [<ffffffff8271322f>] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778 [<ffffffff827132da>] driver_probe_device+0x2a/0x120 drivers/base/dd.c:808 [<ffffffff82713c27>] __device_attach_driver+0xf7/0x150 drivers/base/dd.c:936 [<ffffffff82710137>] bus_for_each_drv+0xb7/0x100 drivers/base/bus.c:427 [<ffffffff827136b5>] __device_attach+0x105/0x2d0 drivers/base/dd.c:1008 [<ffffffff82711d36>] bus_probe_device+0xc6/0xe0 drivers/base/bus.c:487 [<ffffffff8270e242>] device_add+0x642/0xdc0 drivers/base/core.c:3517 [<ffffffff82d14d5f>] usb_set_configuration+0x8ef/0xb80 drivers/usb/core/message.c:2170 [<ffffffff82d2576c>] usb_generic_driver_probe+0x8c/0xc0 drivers/usb/core/generic.c:238 [<ffffffff82d16ffc>] usb_probe_device+0x5c/0x140 drivers/usb/core/driver.c:293 [<ffffffff82712f0d>] call_driver_probe drivers/base/dd.c:560 [inline] [<ffffffff82712f0d>] really_probe+0x12d/0x390 drivers/base/dd.c:639 [<ffffffff8271322f>] __driver_probe_device+0xbf/0x140 drivers/base/dd.c:778

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

Affected Software

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

References

• https://git.kernel.org/stable/c/3b3d3127f5b4291ae4caaf50f7b66089ad600480
• https://git.kernel.org/stable/c/3931014367ef31d26af65386a4ca496f50f0cfdf
• https://git.kernel.org/stable/c/64fa364ad3245508d393e16ed4886f92d7eb423c
• https://git.kernel.org/stable/c/1b4c08844628dfc8d72d3f51b657f2a5e63b7b4b
• https://git.kernel.org/stable/c/b76449ee75e21acfe9fa4c653d8598f191ed7d68

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