Fix OSS-Fuzz #454273637: UAF with printf optimization and const output #20261
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Note that ZEND_COPY_TMP isn't even valid for CONSTs, and we would need to add a ref even if it were, so just add special handling instead to simplify it.
ndossche
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iluuu1994
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Oct 22, 2025
| zend_emit_op(NULL, ZEND_ECHO, &rope_result, NULL); | ||
| zend_emit_op_tmp(result, ZEND_STRLEN, ©, NULL); | ||
| if (rope_result.op_type != IS_CONST) { | ||
| /* Note: ZEND_COPY_TMP is only valid for TMPVAR. */ |
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Maybe ZEND_ASSERT(rope_result.op_type == IS_TMP_VAR);?
TimWolla
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Oct 23, 2025
| { | ||
| /* Special case: printf with a single constant string argument and no format specifiers. | ||
| * In this case, just emit ECHO and return the string length if needed. */ | ||
| if (args->children == 1) { |
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Is this entire branch obsolete now?
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I can't check but I guess so, although this still skips some work.
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Note that ZEND_COPY_TMP isn't even valid for CONSTs, and we would need to add a ref even if it were, so just add special handling instead to simplify it.
Regressed in #19658
Issue: https://issues.oss-fuzz.com/issues/454273637