ghostscript: CVE-2016-8602, CVE-2017-7975

ghostscript: CVE-2016-8602, CVE-2017-7975

The .sethalftone5 function in psi/zht2.c in Ghostscript before 9.21 allows remote
attackers to cause a denial of service (application crash) or possibly execute
arbitrary code via a crafted Postscript document that calls .sethalftone5 with an
empty operand stack.

Artifex jbig2dec 0.13, as used in Ghostscript, allows out-of-bounds writes because
of an integer overflow in the jbig2_build_huffman_table function in jbig2_huffman.c
during operations on a crafted JBIG2 file, leading to a denial of service (application
crash) or possibly execution of arbitrary code.

References:
https://nvd.nist.gov/vuln/detail/CVE-2016-8602
https://nvd.nist.gov/vuln/detail/CVE-2017-7975

Upstream patches:
http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=f5c7555c303
http://git.ghostscript.com/?p=ghostpdl.git;a=commitdiff;h=5e57e483298

Signed-off-by: Catalin Enache <catalin.enache@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>