Make sure to extract absolute file paths on exec #166
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MatteoNardi
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Mar 24, 2023
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misc(bpf): cleanup get_path
Tests were failing because we were searching in rules maps (target and whitelist map) an image which contained potential garbage after the filename.
On busybox-based embedded systems, `which echo` returns `/bin/echo`, which is a symlink to `/bin/busybox`. On relative path execution, our `sched_process_exec` handler takes the path from `bprm->filename`, which leads to the linked at file. For this reason we need to use `canonicalize()` in the relative exec test case.
The LOOP macro now takes an extra `max_unroll` parameter, which defines the maximum loop unroll when bpf_loop is missing. This allows in `get_path_str` to have a MAX_PATH_COMPONENTS of 100, but unroll the loop only up to 20, since a bigger value would be rejected by the verifier.
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banditopazzo
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banditopazzo
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Fix process-monitor to always get the absolute file path on exec.
Before this change executing a file with a relative path would have resulted in an exec event with path
./executable. After this change it will be/path/to/executable.Since the code to extract the full file path is quite complex, we'll execute it only when needed.
I have
cargo fmt;cargo clippy;cargo testand all tests pass;