- Update to version 2.3.0
* [x86-64] mold 2.3.0 has introduced an experimental flag, -z rewrite-endbr, which
rewrites superfluous endbr64 instructions as nop.
* endbr64 is a relatively recent x86 instruction used to mark locations where an
indirect jump instruction can transfer control. With control-flow integrity
enabled (meaning endbr64 is effective), an indirect jump can only target an
endbr64 or it will trigger a runtime exception. This mechanism significantly
hinders certain control hijacking attacks, such as ROP or JOP, since attackers
cannot jump to just any location.
* When given the -fcf-protection flag, GCC conservatively places an endbr64 at the
beginning of every global function. This is because the function's address might
be taken as a pointer by other translation units. However, in most cases,
function addresses are not actually taken. This conservative approach results in
an overabundance of unnecessary endbr64 instructions, leading to not only code
bloating but also a potential decrease in security as there are more locations
for an attacker to exploit.
* The new linker option, -z rewrite-endbr, aims to alleviate this issue. The
linker can carry out a whole-program analysis on the input files to identify
functions whose addresses are never taken. If -z rewrite-endbr is specified,
mold will conduct this analysis and replace the initial endbr64 with a nop for
functions whose addresses aren't taken. (17f0d85)
* mold now produces a more compact .gdb_index section when using the --gdb-index
flag. Additionally, mold now generates a correct .gdb_index section for object
files created by Clang. (a396fa4)
* mold is now capable of handling input sections larger than 4 GiB. (0ce32d3)
* [PPC] mold can now generate executables for POWER10 processors. Previously,
executables produced by mold would crash immediately on startup on POWER10.
(0f71471)
* [ARM64] When a function with a non-standard calling convention is exported, it's
mandatory for the linker to turn on the STO_AARCH64_VARIANT_PCS flag to notify