CVE-2024-40974

Summary

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

powerpc/pseries: Enforce hcall result buffer validity and size

plpar_hcall(), plpar_hcall9(), and related functions expect callers to provide valid result buffers of certain minimum size. Currently this is communicated only through comments in the code and the compiler has no idea.

For example, if I write a bug like this:

long retbuf[PLPAR_HCALL_BUFSIZE]; // should be PLPAR_HCALL9_BUFSIZE plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, …);

This compiles with no diagnostics emitted, but likely results in stack corruption at runtime when plpar_hcall9() stores results past the end of the array. (To be clear this is a contrived example and I have not found a real instance yet.)

To make this class of error less likely, we can use explicitly-sized array parameters instead of pointers in the declarations for the hcall APIs. When compiled with -Warray-bounds[1], the code above now provokes a diagnostic like this:

error: array argument is too small; is of size 32, callee requires at least 72 [-Werror,-Warray-bounds] 60 | plpar_hcall9(H_ALLOCATE_VAS_WINDOW, retbuf, | ^ ~~~~~~

[1] Enabled for LLVM builds but not GCC for now. See commit 0da6e5fd6c37 ("gcc: disable '-Warray-bounds' for gcc-13 too") and related changes.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < acf2b80c31c37acab040baa3cf5f19fbd5140b18affected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < 19c166ee42cf16d8b156a6cb4544122d9a65d3caaffected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < a8c988d752b3d98d5cc1e3929c519a55ef55426caffected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < 262e942ff5a839b9e4f3302a8987928b0c8b8a2daffected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < 8aa11aa001576bf3b00dcb8559564ad7a3113588affected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < 3ad0034910a57aa88ed9976b1431b7b8c84e0048affected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < aa6107dcc4ce9a3451f2d729204713783b657257affected
LinuxLinuxb9377ffc3a03cde558d76349a262a1adbb6d3112 < ff2e185cf73df480ec69675936c4ee75a445c3e4affected
LinuxLinux2.6.19affected
LinuxLinux0 < 2.6.19unaffected
LinuxLinux4.19.317 <= 4.19.*unaffected
LinuxLinux5.4.279 <= 5.4.*unaffected
LinuxLinux5.10.221 <= 5.10.*unaffected
LinuxLinux5.15.162 <= 5.15.*unaffected
LinuxLinux6.1.96 <= 6.1.*unaffected
LinuxLinux6.6.36 <= 6.6.*unaffected
LinuxLinux6.9.7 <= 6.9.*unaffected
LinuxLinux6.10 <= *unaffected

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References