CVE-2022-50828

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

clk: zynqmp: Fix stack-out-of-bounds in strncpy`

BUG: KASAN: stack-out-of-bounds in strncpy+0x30/0x68

Linux-ATF interface is using 16 bytes of SMC payload. In case clock name is longer than 15 bytes, string terminated NULL character will not be received by Linux. Add explicit NULL character at last byte to fix issues when clock name is longer.

This fixes below bug reported by KASAN:

================================================================== BUG: KASAN: stack-out-of-bounds in strncpy+0x30/0x68 Read of size 1 at addr ffff0008c89a7410 by task swapper/0/1

CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.4.0-00396-g81ef9e7-dirty #3 Hardware name: Xilinx Versal vck190 Eval board revA (QSPI) (DT) Call trace: dump_backtrace+0x0/0x1e8 show_stack+0x14/0x20 dump_stack+0xd4/0x108 print_address_description.isra.0+0xbc/0x37c __kasan_report+0x144/0x198 kasan_report+0xc/0x18 __asan_load1+0x5c/0x68 strncpy+0x30/0x68 zynqmp_clock_probe+0x238/0x7b8 platform_drv_probe+0x6c/0xc8 really_probe+0x14c/0x418 driver_probe_device+0x74/0x130 __device_attach_driver+0xc4/0xe8 bus_for_each_drv+0xec/0x150 __device_attach+0x160/0x1d8 device_initial_probe+0x10/0x18 bus_probe_device+0xe0/0xf0 device_add+0x528/0x950 of_device_add+0x5c/0x80 of_platform_device_create_pdata+0x120/0x168 of_platform_bus_create+0x244/0x4e0 of_platform_populate+0x50/0xe8 zynqmp_firmware_probe+0x370/0x3a8 platform_drv_probe+0x6c/0xc8 really_probe+0x14c/0x418 driver_probe_device+0x74/0x130 device_driver_attach+0x94/0xa0 __driver_attach+0x70/0x108 bus_for_each_dev+0xe4/0x158 driver_attach+0x30/0x40 bus_add_driver+0x21c/0x2b8 driver_register+0xbc/0x1d0 __platform_driver_register+0x7c/0x88 zynqmp_firmware_driver_init+0x1c/0x24 do_one_initcall+0xa4/0x234 kernel_init_freeable+0x1b0/0x24c kernel_init+0x10/0x110 ret_from_fork+0x10/0x18

The buggy address belongs to the page: page:ffff0008f9be1c88 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 raw: 0008d00000000000 ffff0008f9be1c90 ffff0008f9be1c90 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff page dumped because: kasan: bad access detected

addr ffff0008c89a7410 is located in stack of task swapper/0/1 at offset 112 in frame: zynqmp_clock_probe+0x0/0x7b8

this frame has 3 objects: [32, 44) response [64, 80) ret_payload [96, 112) name

Memory state around the buggy address: ffff0008c89a7300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0008c89a7380: 00 00 00 00 f1 f1 f1 f1 00 04 f2 f2 00 00 f2 f2

ffff0008c89a7400: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 ^ ffff0008c89a7480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff0008c89a7500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================

Affected Software

References

• https://git.kernel.org/stable/c/0a07b13af04d0db7325018aaa83b5ffe864790c9
• https://git.kernel.org/stable/c/5dbfcf7b080306b65d9f756fadf46c9495793750
• https://git.kernel.org/stable/c/bce41e4ac6f5ca3b22a07e8cdadc12044bbf9d3b
• https://git.kernel.org/stable/c/d66fea97671fcb516bd6d34bcc033f650ac7ee91
• https://git.kernel.org/stable/c/d9e2585c3bcecb1c83febad31b9f450e93d2509e
• https://git.kernel.org/stable/c/dd80fb2dbf1cd8751efbe4e53e54056f56a9b115