match: avoid segmentation fault with no_regex #332
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In f398927 (Use different colors for subpattern matches., 2023-01-09), `match_pattern()` was changed so that the `sp` and `ep` pointers no longer refer to a single start/end but to an array. Unfortunately, the `match()` function that is used in the no-regex case was not adjusted correctly. While it does advance `sp` and `ep` to the next array elements in case of a match, that advancement is only visible to the `match()` function, but not to its caller, `match_pattern()`, which subsequently assigns `*sp = *ep = NULL`, overwriting the values that were assigned by the `match()` function. As a consequence, the invariant where `search_range()` expects the `sp`/`ep` values to be non-`NULL` if `match_pattern()` returns non-zero is violated, and the `hilite_line()` function will call `create_hilites()` with those invalid values and subsequently access memory at an insanely large `start_index`, and crash. Fix this by changing the `match()` function in a way where the `sp`/`ep` modifications are visible to its caller. Signed-off-by: Johannes Schindelin <[email protected]>
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In f398927 (Use different colors for subpattern matches., 2023-01-09),
match_pattern()was changed so that thespandeppointers no longer refer to a single start/end but to an array.Unfortunately, the
match()function that is used in the no-regex case was not adjusted correctly. While it does advancespandepto the next array elements in case of a match, that advancement is only visible to thematch()function, but not to its caller,match_pattern(), which subsequently assigns*sp = *ep = NULL, overwriting the values that were assigned by thematch()function.As a consequence, the invariant where
search_range()expects thesp/epvalues to be non-NULLifmatch_pattern()returns non-zero is violated, and thehilite_line()function will callcreate_hilites()with those invalid values and subsequently access memory at an insanely largestart_index, and crash.Fix this by changing the
match()function in a way where thesp/epmodifications are visible to its caller.