Package signatures

To ensure the integrity of the libjpeg-turbo binary packages, the RPM and DEB files and the source tarball are signed using the following key:
http://www.libjpeg-turbo.org/key/LJT-GPG-KEY-1024
http://pgp.mit.edu/pks/lookup?op=get&search=0x85C7044E033FDE16
and the Windows installers are signed using a code signing certificate.

Packaging changes

• The OS X binaries are now built using GCC 5.x, which improves performance relative to libjpeg-turbo 1.4.1, particularly when using i386 code.
• The Linux binaries now require GLIBC 2.5 or later (RHEL 5 or equivalent vintage.)
• The source has been processed with a recent version of autotools, so it should no longer be necessary to run autoreconf on it before building iOS binaries.

Cygwin

See http://www.libjpeg-turbo.org/Documentation/Cygwin for Cygwin installation instructions.

1.4.2

Significant changes relative to 1.4.1

1. Fixed an issue whereby cjpeg would segfault if a Windows bitmap with a negative width or height was used as an input image (Windows bitmaps can have a negative height if they are stored in top-down order, but such files are rare and not supported by libjpeg-turbo.)

2. Fixed an issue whereby, under certain circumstances, libjpeg-turbo would incorrectly encode certain JPEG images when quality=100 and the fast integer forward DCT were used. This was known to cause make test to fail when the library was built with -march=haswell on x86 systems.

3. Fixed an issue whereby libjpeg-turbo would crash when built with the latest & greatest development version of the Clang/LLVM compiler. This was caused by an x86-64 ABI conformance issue in some of libjpeg-turbo's 64-bit SSE2 SIMD routines. Those routines were incorrectly using a 64-bit mov instruction to transfer a 32-bit JDIMENSION argument, whereas the x86-64 ABI allows the upper (unused) 32 bits of a 32-bit argument's register to be undefined. The new Clang/LLVM optimizer uses load combining to transfer multiple adjacent 32-bit structure members into a single 64-bit register, and this exposed the ABI conformance issue.

4. Fixed a bug in the MIPS DSPr2 4:2:0 "plain" (non-fancy and non-merged) upsampling routine that caused a buffer overflow (and subsequent segfault) when decompressing a 4:2:0 JPEG image whose scaled output width was less than 16 pixels. The "plain" upsampling routines are normally only used when decompressing a non-YCbCr JPEG image, but they are also used when decompressing a JPEG image whose scaled output height is 1.

5. Fixed various negative left shifts and other issues reported by the GCC and Clang undefined behavior sanitizers. None of these was known to pose a security threat, but removing the warnings makes it easier to detect actual security issues, should they arise in the future.