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libraries: Fix multiplications converted to a larger type - #7705
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Cast the first operand so that products assigned to or compared with size_t, ssize_t, long, and off_t values are computed in the wide type instead of int, which can overflow for large dimensions. This covers buffer sizes in the png and cairo drivers, gmath filter kernels, the ccmath calloc calls, linkm chunk allocation, raster row buffers, raster3d tile and volume sizes, segment addressing, and diglib reallocation. Fixes 24 CodeQL cpp/integer-multiplication-cast-to-long alerts.
This was referenced Jul 14, 2026
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Fixes 24 CodeQL
cpp/integer-multiplication-cast-to-longalerts across the C libraries (all remaining library alerts for this rule outside lib/ogsf and lib/nviz, which are in #7704).All are the same pattern: an
int * intproduct assigned to (or compared with) a wider type (size_t,ssize_t,long,off_t), so the multiplication could overflow before widening for very large dimensions. The fix casts the first operand so the product is computed in the destination type, following the idiom from ed986f8. Touched: png/cairo driver buffer sizes, gmath filter kernels (del2g.c,getg.c), the two ccmathcalloccalls, linkm chunk allocation, raster row buffers (get_row.c,put_row.c), raster3d tile/cache/volume sizes, segment addressing, and diglib reallocation.Verification: all nine libraries compile cleanly; runtime smoke tests exercise the touched paths (r.mapcalc + r.univar round trip for raster row I/O, r3.mapcalc + r3.univar for raster3d tile I/O, d.rast renders through both the png and cairo drivers, and the earlier v.unpack testsuite run covers diglib).
This is part of a larger effort to work through the open code scanning alerts, grouped into small PRs by issue type.
Written with the assistance of Claude Code.