Reduce the number of md5c.c between the three of these from two to one
by just reaching into the kernel build for both userland builds. The
precedent for this already exists for sha2 in both cases.
_libmd_ symbol privatization bits have been moved to sys/md5.h and
md5.h remains to #include <sys/md5.h> for compatibility.
This stops exporting MD5Pad() in the process because the kernel stopped
exporting it in 502a35d60f. soversion is bumped accordingly.
This also renames the libc version of stack_protector.c; it previously
only worked by coincidence because .PATH ordering worked out such that
we got the right one, but this is not the case anymore. Remove the
landmine.
PR: 280784 (exp-run)
Reviewed by: allanjude, delphij
Differential Revision: https://reviews.freebsd.org/D34497
GCC emits a warning about shadowing a builtin with our mempcpy
declaration, so switch it to using the same model as memcpy() and
use the apparently-existing __builtin___mempcpy_chk().
Reviewed by: kib (earlier version), markj
Sponsored by: Klara, Inc.
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D45976
ssp/ssp.h needed some improvements:
- `len` isn't always a size_t, it may need casted
- In some cases we may want to use a len that isn't specified as a
parameter (e.g., L_ctermid), so __ssp_redirect() should be more
flexible.
- In other cases we may want additional checking, so pull all of the
declaration bits out of __ssp_redirect_raw() so that some functions
can implement the body themselves.
strlcat/strlcpy should be the last of the fortified functions that get
their own __*_chk symbols, and these cases are only done to be
consistent with the rest of the str*() set.
Reviewed by: markj
Sponsored by: Klara, Inc.
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D45679
Switch away from pointer arithmetic to provide more obvious semantics
for checking overlap on pointer ranges. This lets us remove some casts
that need not exist and removes some possible fragility in its use.
While we're here, check for overflow just in case; sometimes we use a
caller-supplied size if __builtin_object_size(3) can't deduce the buffer
size, and we should fail the check if the size is nonsensical for the
provided buffers.
Reviewed by: markj
Sponsored by: Klara, Inc.
Sponsored by: Stormshield
We'll be using it in some upcoming definitions in headers, so move it
back now but slap a warning on it. Our upcoming uses will all be inside
of inline functions, so we're not overly concerned about double
evaluation immediately.
Reviewed by: markj
Sponsored by: Klara, Inc.
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D45677
This is a mostly-unmodified copy of the various *_chk implementations
and headers from NetBSD, without yet modifying system headers to start
actually including them. A future commit will also apply the needed
bits to fix ssp/unistd.h.
Reviewed by: imp, pauamma_gundo.com (both previous versions), kib
Sponsored by: Stormshield
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D32306
These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Keep those.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D42385
With GCC 4.2 out of the tree for a while now and no sign of it
returning, we don't really need to support older versions that don't
allow us to specify a ctor priority anymore.
Noticed by: mjg
This option was added as a transition aide when symbol versioning was
first added. It was enabled by default in 2007 and is supported even
by the old GPLv2 binutils. Trying to disable it currently fails to
build in libc and at this point it isn't worth fixing the build.
Reported by: Michael Dexter
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D24637
A future commit will rebuild this as part of libssp. The exact warnings are
fairly trivially fixed:
- No previous declaration for __stack_chk_guard
- idx is the wrong type, nitems yields a size_t
- Casting away volatile on the tmp_stack_chk_guard directly is a no-no.
Reviewed by: kib, emaste, pfg, Oliver Pinter (earlier version)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22943
__has_attribute(__constructor__) is a better test for clang than
defined(__clang__). Switch to it instead.
While we're already here and touching it, pfg@ nailed down when GCC actually
introduced the priority argument -- 4.3. Use that instead of our
hammer-guess of GCC >= 5 for the sake of correctness.
The preproc logic was added at the last minute to appease GCC 4.2, and
kevans@ did clearly not go back and double-check that the logic worked out
for clang builds to use the new variant.
It turns out that clang defines __GNUC__ == 4. Flip it around and check
__clang__ as well, leaving a note to remove it later.
Reported by: cem
First, this commit is a NOP on GCC <= 4.x; this decidedly doesn't work
cleanly on GCC 4.2, and it will be gone soon anyways so I chose not to dump
time into figuring out if there's a way to make it work. xtoolchain-gcc,
clocking in as GCC6, can cope with it just fine and later versions are also
generally ok with the syntax. I suspect very few users are running GCC4.2
built worlds and also experiencing potential fallout from the status quo.
For dynamically linked applications, this change also means very little.
rtld will run libc ctors before most others, so the situation is
approximately a NOP for these as well.
The real cause for this change is statically linked applications doing
almost questionable things in their constructors. qemu-user-static, for
instance, creates a thread in a global constructor for their async rcu
callbacks. In general, this works in other places-
- On OpenBSD, __stack_chk_guard is stored in an .openbsd.randomdata section
that's initialized by the kernel in the static case, or ld.so in the
dynamic case
- On Linux, __stack_chk_guard is apparently stored in TLS and such a problem
is circumvented there because the value is presumed stable in the new
thread.
On FreeBSD, the rcu thread creation ctor and __guard_setup are both unmarked
priority. qemu-user-static spins up the rcu thread prior to __guard_setup
which starts making function calls- some of these are sprinkled with the
canary. In the middle of one of these functions, __guard_setup is invoked in
the main thread and __stack_chk_guard changes- qemu-user-static is promptly
terminated for an SSP violation that didn't actually happen.
This is not an all-too-common problem. We circumvent it here by giving the
__stack_chk_guard constructor a solid priority. 200 was chosen because that
gives static applications ample range (down to 101) for working around it
if they really need to. I suspect most applications will "just work" as
expected- the default/non-prioritized flavor of __constructor__ functions
run last, and the canary is generally not expected to change as of this
point at the very least.
This took approximately three weeks of spare time debugging to pin down.
PR: 241905
This is necessary to make sure that functions that can have stack
protection are not used to update the stack guard. If not, the stack
guard check would fail when it shouldn't.
guard_setup() calls elf_aux_info(), which, in turn, calls memcpy() to
update stack_chk_guard. If either elf_aux_info() or memcpy() have
stack protection enabled, __stack_chk_guard will be modified before
returning from them, causing the stack protection check to fail.
This change uses a temporary buffer to delay changing
__stack_chk_guard until elf_aux_info() returns.
Submitted by: Luis Pires
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D15173
According to style(9):
> normally, include <sys/types.h> OR <sys/param.h>, but not both.
(<sys/param.h> already includes <sys/types.h> when LOCORE is not defined).
The comment in the libc/sys symbol map referenced the generated symbols
for the syscall trampolines. Such comment was out of place in the secure
symbol map so remove the stale comment and attempt to clarify the old one
to avoid risks of confusion.
Pointed out by: kib
As part of the code refactoring to support FORTIFY_SOURCE we want
a new subdirectory "secure" to keep the files related to security.
Move the stack protector functions to this new directory.
No functional change.
Differential Review: https://reviews.freebsd.org/D3333
