Previously, TLS data was always zero-initialized.
To support initializing the values of TLS data, sys$allocate_tls now
receives a buffer with the desired initial data, and copies it to the
master TLS region of the process.
The DynamicLinker gathers the initial TLS image and passes it to
sys$allocate_tls.
We also now require the size passed to sys$allocate_tls to be
page-aligned, to make things easier. Note that this doesn't waste memory
as the TLS data has to be allocated in separate pages anyway.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This achieves two things:
- Programs can now intentionally perform arbitrary syscalls by calling
syscall(). This allows us to work on things like syscall fuzzing.
- It restricts the ability of userspace to make syscalls to a single
4KB page of code. In order to call the kernel directly, an attacker
must now locate this page and call through it.
