net: lan743x: fix potential out-of-bounds write in lan743x_ptp_io_event_clock_get()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: net: lan743x: fix potential out-of-bounds write in lan743x_ptp_io_event_clock_get() Before calling lan743x_ptp_io_event_clock_get(), the 'channel' value is checked against the maximum value of PCI11X1X_PTP_IO_MAX_CHANNELS(8). This seems correct and aligns with the PTP interrupt status register (PTP_INT_STS) specifications. However, lan743x_ptp_io_event_clock_get() writes to ptp->extts[] with only LAN743X_PTP_N_EXTTS(4) elements, using channel as an index: lan743x_ptp_io_event_clock_get(..., u8 channel,...) { ... /* Update Local timestamp */ extts = &ptp->extts[channel]; extts->ts.tv_sec = sec; ... } To avoid an out-of-bounds write and utilize all the supported GPIO inputs, set LAN743X_PTP_N_EXTTS to 8. Detected using the static analysis tool - Svace.

References

• https://git.kernel.org/stable/c/e8d48201a132f4aab31351c19a802c5a5ae820fa
• https://git.kernel.org/stable/c/66bba1fd5bad548c03f7e42669a59f3f4d8211cc
• https://git.kernel.org/stable/c/41017bd66c533f7af912c58273c7dfd5de0065d4
• https://git.kernel.org/stable/c/4da0d23516857230b8e9b3022e25422ee2e2ba80
• https://git.kernel.org/stable/c/e353b0854d3a1a31cb061df8d022fbfea53a0f24