Lagom: Add an ELF fuzzer, and tweak the code to survive a few minutes… #3071
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… of fuzzing If a buffer smaller than Elf32_Ehdr was passed to Image, header() would do an out-of-bounds read. Make parse() check for that. Make most Image methods assert that the image is_valid(). For that to work, set m_valid early in Image::parse() instead of only at its end. Also reorder a few things so that the fuzzer doesn't hit (valid) assertions, which were harmless from a security PoV but which still allowed userspace to crash the kernel with an invalid ELF file. Make dbgprintf()s configurable at run time so that the fuzzer doesn't produce lots of logspam.
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… of fuzzing
If a buffer smaller than Elf32_Ehdr was passed to Image, header()
would do an out-of-bounds read.
Make parse() check for that. Make most Image methods assert that the image
is_valid(). For that to work, set m_valid early in Image::parse()
instead of only at its end.
Also reorder a few things so that the fuzzer doesn't hit (valid)
assertions, which were harmless from a security PoV but which still
allowed userspace to crash the kernel with an invalid ELF file.
Make dbgprintf()s configurable at run time so that the fuzzer doesn't
produce lots of logspam.
--
Since I had to make LibELF build in Lagom for the recent disasm change, adding a fuzzer was ~free, so why not. (Fixing the few things it found wasn't free.)