Validate instructions #593
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added 4 commits
October 29, 2024 12:42
Signed-off-by: Alan Jowett <[email protected]>
Signed-off-by: Alan Jowett <[email protected]>
Signed-off-by: Alan Jowett <[email protected]>
Signed-off-by: Alan Jowett <[email protected]>
hawkinsw
reviewed
Oct 31, 2024
| .destination_lower_bound = BPF_REG_0, | ||
| .destination_upper_bound = BPF_REG_9, | ||
| .immediate_lower_bound = 0, | ||
| .immediate_upper_bound = 64, |
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This does seem to handle the upper limit, but according to the spec, not every value between 0 and 64 is valid. Only the values 16, 32, and 64 are allowed (https://www.ietf.org/archive/id/draft-ietf-bpf-isa-04.html#section-4.2-5). Does the filter technique here handle that?
| *errmsg = ubpf_error("Invalid offset value %d for opcode %2X.", insts.offset, insts.opcode); | ||
| return false; | ||
| } | ||
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Are we able to validate things that are within the opcode and need to have specific values? In particular, the ALU64 endianness instruction is defined such that source operand field is 0: https://www.ietf.org/archive/id/draft-ietf-bpf-isa-04.html#section-4.2-3
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This pull request includes several changes to the
ubpflibrary, focusing on instruction validation and updating the build configuration. The most important changes include adding a new source file to the build, introducing a function to validate instructions, and integrating this validation into the instruction validation process.Build Configuration:
vm/CMakeLists.txt: Addedubpf_instruction_valid.cto the list of source files.Instruction Validation:
vm/ubpf_int.h: Introduced theubpf_is_valid_instructionfunction to check if an instruction is supported and provide an error message if it is not.vm/ubpf_vm.c: Integrated theubpf_is_valid_instructionfunction into the existing instruction validation process to ensure unsupported instructions are caught and reported.