Refactor DynamicLoader construction with a try_create() helper so that
we can call mmap() before making a loader. This way the loader doesn't
need to have an "mmap failed" state.
This patch also takes care of determining the ELF file size in
try_create() instead of expecting callers to provide it.
Section names are referred to by offset and length. We do not check
(and probably should not check) whether these names overlap in any way.
This opened the door to many sections (in this example: about 2700)
forcing ELF::Image::m_sections to contain endless copies of the same
huge string (in this case: 882K).
Fix this by loading only the first PAGE_SIZE bytes of each name.
Since section names are only relevant for relocations and debug
information and most section names are hard-coded (and far below 4096
bytes) anyway, this should be no restriction at all for 'normal'
executables.
Found by OSS-Fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29187
Previously regions were stored in a vector and then a pointer to
regions in this vector were taken and stored. The problem is the vector
were still appended after pointers were taken, if enough regions were
present the vector would grow so large that it needed a resize, this
cause his memory to moved and now the previous pointers are now
pointing to old memory we just freed.
Fixes#5160
To support upcoming W^X changes in the kernel, the dynamic loader needs
to be careful about the order in which permissions are added to shared
library text segments.
We now start by mapping text segments read-only (no-write, no-exec).
If relocations are needed, we make them writable, and then finally,
for all text segments, we finish by making them read+exec.
Use mmap() with the new MAP_RANDOMIZED flag to load shared libraries at
random addresses in each process.
To avoid address space collisions, we start by doing a large chunk mmap
that covers enough VM for both text and data, then we unmap and remap
the data segment separately, once we know everything will fit.
This is pretty cool! :^)
A C++ source file containing just
#include <LibFoo/Bar.h>
should always compile cleanly.
This patch adds missing header inclusions that could have caused weird error
messages if they were used in a different context. Also, this confused QtCreator.
Similar to LibC storing an assertion message before aborting, process
death by pledge violation now sets a "pledge_violation" key with the
respective pledge name as value in its coredump metadata, which the
CrashReporter will then show.
This is in preparation of adding (much) more process information to
coredumps. As we can only have one null-terminated char[] of arbitrary
length in each struct it's now a single JSON blob, which is a great fit:
easily extensible in the future and allows for key/value pairs and even
nested objects, which will be used e.g. for the process environment, for
example.
