fix(rla): terminate the subimage chain and bounds-check the offset table - #5403
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RLA subimages are concatenated, each header's NextOffset giving the start of the next. Nothing required NextOffset to advance, so a file pointing it at itself or backwards supplied subimages endlessly and any caller enumerating them never terminated. Require it to point past the current header. seek_subimage() now also gives up its current subimage before overwriting the header and scanline offset table, so failing partway leaves no current subimage rather than a mismatched header, table, and spec. read_native_scanline() bounds-checks the scanline index against the offset table instead of asserting that the table matches the spec height -- false for field-rendered images, where the height is halved but the table is not. Assisted-by: Claude Code / Claude Opus 5 Signed-off-by: Larry Gritz <lg@larrygritz.com>
brechtvl
approved these changes
Aug 15, 2026
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More detection of various creative corruptions.
RLA subimages are concatenated, each header's NextOffset giving the start of the next. Nothing required NextOffset to advance, so a file pointing it at itself or backwards supplied subimages endlessly and any caller enumerating them never terminated. Require it to point past the current header.
seek_subimage() now also gives up its current subimage before overwriting the header and scanline offset table, so failing partway leaves no current subimage rather than a mismatched header, table, and spec.
read_native_scanline() bounds-checks the scanline index against the offset table instead of asserting that the table matches the spec height -- false for field-rendered images, where the height is halved but the table is not.
Assisted-by: Claude Code / Claude Opus 5