Description

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

serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO

The SC16IS7XX IC supports a burst mode to access the FIFOs where the
initial register address is sent ($00), followed by all the FIFO data
without having to resend the register address each time. In this mode, the
IC doesn't increment the register address for each R/W byte.

The regmap_raw_read() and regmap_raw_write() are functions which can
perform IO over multiple registers. They are currently used to read/write
from/to the FIFO, and although they operate correctly in this burst mode on
the SPI bus, they would corrupt the regmap cache if it was not disabled
manually. The reason is that when the R/W size is more than 1 byte, these
functions assume that the register address is incremented and handle the
cache accordingly.

Convert FIFO R/W functions to use the regmap _noinc_ versions in order to
remove the manual cache control which was a workaround when using the
_raw_ versions. FIFO registers are properly declared as volatile so
cache will not be used/updated for FIFO accesses.

Classification

CVE ID: CVE-2023-52488

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 12.41% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/4e37416e4ee1b1bc17364a68973e0c63be89e611
https://git.kernel.org/stable/c/e635f652696ef6f1230621cfd89c350cb5ec6169
https://git.kernel.org/stable/c/416b10d2817c94db86829fb92ad43ce7d002c573
https://git.kernel.org/stable/c/084c24e788d9cf29c55564de368bf5284f2bb5db
https://git.kernel.org/stable/c/aa7cb4787698add9367b19f7afc667662c9bdb23
https://git.kernel.org/stable/c/dbf4ab821804df071c8b566d9813083125e6d97b

Timeline