Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: platform/x86/amd/hsmp: Reject negative power cap writes in hwmon hsmp_hwmon_write() takes the user-supplied hwmon value as a signed long and assigns "val / MICROWATT_PER_MILLIWATT" to msg.args[0], which is a __u32. MICROWATT_PER_MILLIWATT is an unsigned long, so a negative write to power1_cap (e.g. "echo -1 > power1_cap") is first converted to a huge unsigned value by the division and then stored into the u32 argument. As a result a nonsensical, multi-gigawatt socket power limit is sent to the SMU via HSMP_SET_SOCKET_POWER_LIMIT instead of the write being rejected. Reject negative values with -EINVAL before the conversion. Tested with HSMP enabled: CAP=$(dirname $(grep -l amd_hsmp_hwmon \ /sys/class/hwmon/hwmon*/name | head -1))/power1_cap # negative write echo -1000000 > $CAP ; echo "ret=$?" # valid positive write must still work echo 400000000 > $CAP ; echo "ret=$?" Before: # echo -1000000 > $CAP ; echo "ret=$?" ret=0 <- accepted; bogus limit sent to SMU # echo 400000000 > $CAP ; echo "ret=$?" ret=0 After: # echo -1000000 > $CAP ; echo "ret=$?" bash: echo: write error: Invalid argument ret=1 <- rejected with -EINVAL # echo 400000000 > $CAP ; echo "ret=$?" ret=0 <- valid write still works
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 92c025db52bb94a032eb3d473bb81e62c19ddbd3 before 2c09cadec116eba3fdbcb5d8d8641f6777d4a11f; affected 92c025db52bb94a032eb3d473bb81e62c19ddbd3 before 1b0a3d915320f1600e5ff43f8bc21b73118480b8; affected 92c025db52bb94a032eb3d473bb81e62c19ddbd3 before 3921bb8635ff2836622df1cdf3194d4f3c1835a4 |
| Linux / Linux | affected 6.16; unaffected 0 before 6.16; unaffected 6.18.52 through 6.18.*; unaffected 7.2.6 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.