net: usb: aqc111: fix error handling of usbnet read calls

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: aqc111: fix error handling of usbnet read calls Syzkaller, courtesy of syzbot, identified an error (see report [1]) in aqc111 driver, caused by incomplete sanitation of usb read calls' results. This problem is quite similar to the one fixed in commit 920a9fa27e78 ("net: asix: add proper error handling of usb read errors"). For instance, usbnet_read_cmd() may read fewer than 'size' bytes, even if the caller expected the full amount, and aqc111_read_cmd() will not check its result properly. As [1] shows, this may lead to MAC address in aqc111_bind() being only partly initialized, triggering KMSAN warnings. Fix the issue by verifying that the number of bytes read is as expected and not less. [1] Partial syzbot report: BUG: KMSAN: uninit-value in is_valid_ether_addr include/linux/etherdevice.h:208 [inline] BUG: KMSAN: uninit-value in usbnet_probe+0x2e57/0x4390 drivers/net/usb/usbnet.c:1830 is_valid_ether_addr include/linux/etherdevice.h:208 [inline] usbnet_probe+0x2e57/0x4390 drivers/net/usb/usbnet.c:1830 usb_probe_interface+0xd01/0x1310 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:-1 [inline] really_probe+0x4d1/0xd90 drivers/base/dd.c:658 __driver_probe_device+0x268/0x380 drivers/base/dd.c:800 ... Uninit was stored to memory at: dev_addr_mod+0xb0/0x550 net/core/dev_addr_lists.c:582 __dev_addr_set include/linux/netdevice.h:4874 [inline] eth_hw_addr_set include/linux/etherdevice.h:325 [inline] aqc111_bind+0x35f/0x1150 drivers/net/usb/aqc111.c:717 usbnet_probe+0xbe6/0x4390 drivers/net/usb/usbnet.c:1772 usb_probe_interface+0xd01/0x1310 drivers/usb/core/driver.c:396 ... Uninit was stored to memory at: ether_addr_copy include/linux/etherdevice.h:305 [inline] aqc111_read_perm_mac drivers/net/usb/aqc111.c:663 [inline] aqc111_bind+0x794/0x1150 drivers/net/usb/aqc111.c:713 usbnet_probe+0xbe6/0x4390 drivers/net/usb/usbnet.c:1772 usb_probe_interface+0xd01/0x1310 drivers/usb/core/driver.c:396 call_driver_probe drivers/base/dd.c:-1 [inline] ... Local variable buf.i created at: aqc111_read_perm_mac drivers/net/usb/aqc111.c:656 [inline] aqc111_bind+0x221/0x1150 drivers/net/usb/aqc111.c:713 usbnet_probe+0xbe6/0x4390 drivers/net/usb/usbnet.c:1772

References

• https://git.kernel.org/stable/c/8c97655275482ef5384ce0501640630a0fc0f6f4
• https://git.kernel.org/stable/c/11273279012c922f37cfb4dd95d142803fc07b98
• https://git.kernel.org/stable/c/f398d2dfe450ce2c031d10b585448862d74a0501
• https://git.kernel.org/stable/c/acb47a40b5e38be03ef659b7bacdddc592ed73b7
• https://git.kernel.org/stable/c/60790d287c1a1ced3554d4a87c2f27bf299a932a
• https://git.kernel.org/stable/c/30a9e834c74e260533b8d0885e3c89f6f32f7993
• https://git.kernel.org/stable/c/7c01863b1c47f040d9674171e77789a423b9b128
• https://git.kernel.org/stable/c/405b0d610745fb5e84fc2961d9b960abb9f3d107