Avoid potential pointer overflow/underflow in png_handle_sPLT() and
png_handle_pCAL() (Bug report by John Regehr).
Fixed incorrect implementation of png_set_PLTE() that uses png_ptr
not info_ptr, that left png_set_PLTE() open to the CVE-2015-8126
vulnerability.
Backported tests from libpng-1.7.0beta69.
Fixed an error in handling of bad zlib CMINFO field in pngfix, found by
American Fuzzy Lop, reported by Brian Carpenter. inflate() doesn't
immediately fault a bad CMINFO field; instead a 'too far back' error
happens later (at least some times). pngfix failed to limit CMINFO to
the allowed values but then assumed that window_bits was in range,
triggering an assert. The bug is mostly harmless; the PNG file cannot
be fixed.
In libpng 1.6 zlib initialization was changed to use the window size
in the zlib stream, not a fixed value. This causes some invalid images,
where CINFO is too large, to display 'correctly' if the rest of the
data is valid. This provides a workaround for zlib versions where the
error arises (ones that support the API change to use the window size
in the stream).
OBS-URL: https://build.opensuse.org/package/show/graphics/libpng16?expand=0&rev=75
