regression: CopyMem() in ad8692e copies out of bounds #725
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I'm not 100% sure that we can really count on the string being null terminated since other places also seem to just copy the first 100 char16s. |
The CopyMem() introduced in "ad8692e avoid EFIv2 runtime services on Apple x86 machines" copies 100 CHAR16s no matter what. NX enabled firmware catches this and the boot breaks on those systems when the value is smaller than that and it's up against a page boundary with a page that's not mapped as readable. https://uefi.org/specs/UEFI/2.10/04_EFI_System_Table.html says that FirmwareVendor is a pointer to a NUL terminated string that identifies the vendor that produces the system firmware for the platform. Signed-off-by: Jan Setje-Eilers <Jan.SetjeEilers@oracle.com>
vathpela
approved these changes
Feb 19, 2025
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The CopyMem() introduced in
ad8692e avoid EFIv2 runtime services on Apple x86 machines copies 100 CHAR16s no matter what. NX enabled firmware catches this and the boot breaks on those systems.
https://uefi.org/specs/UEFI/2.10/04_EFI_System_Table.html says that FirmwareVendor is a pointer to a null terminated string that identifies the vendor that produces the system firmware for the platform. If we can rely on it being null terminated then we don't need to copy the string at all.