Add check for reproducible build in PE module #1219
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ITAYC0HEN
approved these changes
Apr 6, 2020
wxsBSD
reviewed
Apr 7, 2020
libyara/modules/pe/pe.c
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| @@ -292,6 +292,8 @@ static void pe_parse_debug_directory( | |||
| size_t pdb_path_len; | |||
| char* pdb_path = NULL; | |||
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| set_integer(0, pe->object, "is_reproducible_build"); | |||
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Does it make sense to set this to zero here? What happens if the debug directory entry (or something else we check later on) is corrupt. In this case a user can get an incorrect value (pe.is_reproducible_build would be zero) when it should be UNDEFINED at this point.
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Thank you for your suggestion. Now the value is set to 0 only when debug directory is empty or when code successfully iterated through all entries
Handle cases when the is_reproducible_build should be YR_UNDEFINED instead of 0
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Since there is a code that parses debug directory, I thought it's a good idea to add some value that can be used for checking if the PE binary build as "reproducible build". If this value is set, it means that timestamps in the PE can be replaced with some other values to achieve reproducibility.
Here is more information about reproducible builds:
https://devblogs.microsoft.com/oldnewthing/20180103-00/?p=97705
https://docs.microsoft.com/en-us/windows/win32/debug/pe-format?redirectedfrom=MSDN#debug-type