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Fix EXECUTE/?/DUMP/TYPE/DECIMAL-HEX-OCTAL/ALIGN defects from proof sweep

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proof/FINDINGS.md's Isabelle/HOL word-source sweep (§4) flagged five real
defects; this fixes all five and records resolution in that doc:

- EXECUTE (system_words.c): cast a popped cell straight to a DictEntry*
  and called through it with only a null check. Now validates via a new
  shared vm_dict_entry_ok(), promoted out of starforth_words.c's
  ENTROPY@/ENTROPY! guard (dictionary_management.c) so EXECUTE gets the
  same live-entry check.

- ? and DUMP (format_words.c): dereferenced the popped cell as a raw host
  pointer, bypassing vm_addr_ok entirely (out-of-VM-bounds read). Both now
  go through VM_ADDR/vm_addr_ok/vm_load_cell/vm_ptr like every other
  memory word (@, `,`, editor_words.c).

- TYPE (io_words.c): bounds check computed addr+count in signed 64-bit
  arithmetic, which can overflow and bypass the check on large operands.
  Replaced with vm_addr_ok(), which is written to avoid that overflow.

- DECIMAL/HEX/OCTAL (format_words.c): wrote only the BASE memory cell,
  never vm->base, the host-mirror field number-output words actually read
  via current_base() -- so these words silently affected number parsing
  but never printing. Now call the existing vm_set_base() (previously
  only used at boot init), which updates both. vm_get_base/vm_set_base
  promoted to public declarations in include/vm.h.

- ALIGN vs ALLOT/,/C,/2, (dictionary_words.c): disagreed on dictionary
  growth ceiling (2MB vs 5MB). Investigated which was correct rather than
  blindly widening: vm_get_block_addr() maps block N to
  vm->memory + N*BLOCK_SIZE across the full 5MB arena, and
  USER_BLOCKS_START (block 2048) lines up exactly with
  DICTIONARY_MEMORY_SIZE -- so ALLOT/,/C,/2, letting `here` grow past 2MB
  could silently corrupt live block/user data sharing that memory.
  Tightened ALLOT/,/C,/2, to DICTIONARY_MEMORY_SIZE to match ALIGN.

Verified: hosted (amd64) and kernel (amd64, __STARKERNEL__) both build
clean with -Wall -Werror; hosted POST suite 1012/1012 passing (0
regressions); manually exercised EXECUTE, ?/DUMP, TYPE, HEX/DECIMAL/OCTAL,
and large-ALLOT rejection in the REPL.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014Qf6YcnHgaEtEygq3knx19
This commit is contained in:
Claude
2026-09-05 14:07:11 +00:00
parent 70dc8beba4
commit c36bd99e1e
9 changed files with 85 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/word_source/io_words.c
+10 -6
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@@ -122,22 +122,26 @@ static void io_word_type(VM *vm) {
}
cell_t count = vm_pop(vm);
cell_t addr = vm_pop(vm);
vaddr_t addr = VM_ADDR(vm_pop(vm));
// Add bounds checking
if (addr < 0 || count < 0 || (addr + count) > VM_MEMORY_SIZE) {
log_message(LOG_ERROR, "TYPE: Invalid range [%ld, %ld)", (long) addr, (long) (addr + count));
// Bounds check via vm_addr_ok (avoids the addr+count overflow a manual
// sum would risk for large signed operands)
if (count < 0 || !vm_addr_ok(vm, addr, (size_t) count)) {
log_message(LOG_ERROR, "TYPE: Invalid range [addr=%llu, count=%ld)",
(unsigned long long) addr, (long) count);
vm->error = 1;
return;
}
// Output characters from VM memory
const uint8_t *src = vm_ptr(vm, addr);
for (cell_t i = 0; i < count; i++) {
putchar(vm->memory[addr + i]);
putchar(src[i]);
}
fflush(stdout);
log_message(LOG_DEBUG, "TYPE: Output %ld characters from address %ld", (long) count, (long) addr);
log_message(LOG_DEBUG, "TYPE: Output %ld characters from address %llu",
(long) count, (unsigned long long) addr);
}
/**