CVE-2022-50094 — spmi: trace: fix stack-out-of-bound access in SPMI tracing functions

Affected: Linux

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

spmi: trace: fix stack-out-of-bound access in SPMI tracing functions

trace_spmi_write_begin() and trace_spmi_read_end() both call memcpy() with a length of "len + 1". This leads to one extra byte being read beyond the end of the specified buffer. Fix this out-of-bound memory access by using a length of "len" instead.

Here is a KASAN log showing the issue:

BUG: KASAN: stack-out-of-bounds in trace_event_raw_event_spmi_read_end+0x1d0/0x234 Read of size 2 at addr ffffffc0265b7540 by task thermal@2.0-ser/1314 ... Call trace: dump_backtrace+0x0/0x3e8 show_stack+0x2c/0x3c dump_stack_lvl+0xdc/0x11c print_address_description+0x74/0x384 kasan_report+0x188/0x268 kasan_check_range+0x270/0x2b0 memcpy+0x90/0xe8 trace_event_raw_event_spmi_read_end+0x1d0/0x234 spmi_read_cmd+0x294/0x3ac spmi_ext_register_readl+0x84/0x9c regmap_spmi_ext_read+0x144/0x1b0 [regmap_spmi] _regmap_raw_read+0x40c/0x754 regmap_raw_read+0x3a0/0x514 regmap_bulk_read+0x418/0x494 adc5_gen3_poll_wait_hs+0xe8/0x1e0 [qcom_spmi_adc5_gen3] ... __arm64_sys_read+0x4c/0x60 invoke_syscall+0x80/0x218 el0_svc_common+0xec/0x1c8 ...

addr ffffffc0265b7540 is located in stack of task thermal@2.0-ser/1314 at offset 32 in frame: adc5_gen3_poll_wait_hs+0x0/0x1e0 [qcom_spmi_adc5_gen3]

this frame has 1 object: [32, 33) 'status'

Memory state around the buggy address: ffffffc0265b7400: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 ffffffc026…

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CVE-2022-50094 — spmi: trace: fix stack-out-of-bound access in SPMI tracing functions