6l: call dwarfaddfrag when registering D_FILE symbols#142
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ftab (the file fragment table used by dwarf.c's decodez()) was never populated, causing every z entry lookup to fail with "corrupt z entry". Register each new SFILE symbol's fragment string into ftab via dwarfaddfrag() at the same point histgen is assigned. https://claude.ai/code/session_01WGAwvvTwDg2yknFkmZ3qzs
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This pull request introduces DWARF debugging support to the 6l linker by including the dwarf.h header and invoking dwarfaddfrag during SFILE symbol processing. A potential out-of-bounds read was identified when accessing the symbol name, and a check was suggested to ensure the string is not empty before offsetting the pointer.
| histgen++; | ||
| s->type = SFILE; | ||
| s->value = histgen; | ||
| dwarfaddfrag(s->value, s->name+1); |
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The call to dwarfaddfrag uses s->name+1 to skip the type prefix (typically 'z' or 'f'). While SFILE symbols in this context are expected to have such a prefix, if s->name were an empty string, this would result in an out-of-bounds read. Adding a check for the string length ensures robustness against malformed object files.
if(s->name[0] != '\0')
dwarfaddfrag(s->value, s->name+1);
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ftab (the file fragment table used by dwarf.c's decodez()) was never populated, causing every z entry lookup to fail with "corrupt z entry". Register each new SFILE symbol's fragment string into ftab via dwarfaddfrag() at the same point histgen is assigned.
https://claude.ai/code/session_01WGAwvvTwDg2yknFkmZ3qzs