tiff: memory leak in TIFFFdOpen function in tif_unix.c when using pal2rgb (CVE-2019-6128)

The TIFFFdOpen function in tif_unix.c in LibTIFF 4.0.10 has a memory leak, as demonstrated by pal2rgb.

References:

• http://bugzilla.maptools.org/show_bug.cgi?id=2836
• https://nvd.nist.gov/vuln/detail/CVE-2019-6128

Patch:

https://gitlab.com/libtiff/libtiff/commit/ae0bed1fe530a82faf2e9ea1775109dbf301a971

Affected branches:

• master (b6b47219)
• 3.10-stable (967440f6)
• 3.9-stable (c99c0aa8)
• 3.8-stable (035d2d00)