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HardenedBSD/lib/libsys/interposing_table.c

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Fix known issues which blow up the process after dlopen("libthr.so") (or loading a dso linked to libthr.so into process which was not linked against threading library). - Remove libthr interposers of the libc functions, including __error(). Instead, functions calls are indirected through the interposing table, similar to how pthread stubs in libc are already done. Libc by default points either to syscall trampolines or to existing libc implementations. On libthr load, libthr rewrites the pointers to the cancellable implementations already in libthr. The interposition table is separate from pthreads stubs indirection table to not pull pthreads stubs into static binaries. - Postpone the malloc(3) internal mutexes initialization until libthr is loaded. This avoids recursion between calloc(3) and static pthread_mutex_t initialization. - Reinstall signal handlers with wrapper on libthr load. The _rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2) when libthr is statically referenced from the main binary. In the process, fix openat(2), swapcontext(2) and setcontext(2) interposing. The libc symbols were exported at different versions than libthr interposers. Export both libc and libthr versions from libc now, with default set to the higher version from libthr. Remove unused and disconnected swapcontext(3) userspace implementation from libc/gen. No objections from: deischen Tested by: pho, antoine (exp-run) (previous versions) Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-01-03 19:38:46 +01:00
/*
* Copyright (c) 2014 The FreeBSD Foundation.
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include "libc_private.h"
#define SLOT(a, b) \
[INTERPOS_##a] = (interpos_func_t)b
libc: split libc and syscall interposing (1/2) System calls or their wrappers are now interposed by __libsys_interposing with purely libc entries remaining in __libc_interposing. Use __libsys_interposing_slot in libthr to update __libsys_interposing, but also make __libc_interposing_slot fall back to __libsys_interposing_slot so an out of date libc has a chance of working during updates. Reviewed by: kib, emaste, imp Pull Request: https://github.com/freebsd/freebsd-src/pull/908
2024-01-16 21:16:39 +01:00
interpos_func_t __libsys_interposing[INTERPOS_MAX] = {
Fix known issues which blow up the process after dlopen("libthr.so") (or loading a dso linked to libthr.so into process which was not linked against threading library). - Remove libthr interposers of the libc functions, including __error(). Instead, functions calls are indirected through the interposing table, similar to how pthread stubs in libc are already done. Libc by default points either to syscall trampolines or to existing libc implementations. On libthr load, libthr rewrites the pointers to the cancellable implementations already in libthr. The interposition table is separate from pthreads stubs indirection table to not pull pthreads stubs into static binaries. - Postpone the malloc(3) internal mutexes initialization until libthr is loaded. This avoids recursion between calloc(3) and static pthread_mutex_t initialization. - Reinstall signal handlers with wrapper on libthr load. The _rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2) when libthr is statically referenced from the main binary. In the process, fix openat(2), swapcontext(2) and setcontext(2) interposing. The libc symbols were exported at different versions than libthr interposers. Export both libc and libthr versions from libc now, with default set to the higher version from libthr. Remove unused and disconnected swapcontext(3) userspace implementation from libc/gen. No objections from: deischen Tested by: pho, antoine (exp-run) (previous versions) Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-01-03 19:38:46 +01:00
SLOT(accept, __sys_accept),
SLOT(accept4, __sys_accept4),
SLOT(aio_suspend, __sys_aio_suspend),
SLOT(close, __sys_close),
SLOT(connect, __sys_connect),
The lseek(2), mmap(2), truncate(2), ftruncate(2), pread(2), and pwrite(2) syscalls are wrapped to provide compatibility with pre-7.x kernels which required padding before the off_t parameter. The fcntl(2) contains compatibility code to handle kernels before the struct flock was changed during the 8.x CURRENT development. The shims were reasonable to allow easier revert to the older kernel at that time. Now, two or three major releases later, shims do not serve any purpose. Such old kernels cannot handle current libc, so revert the compatibility code. Make padded syscalls support conditional under the COMPAT6 config option. For COMPAT32, the syscalls were under COMPAT6 already. Remove WITHOUT_SYSCALL_COMPAT build option, which only purpose was to (partially) disable the removed shims. Reviewed by: jhb, imp (previous versions) Discussed with: peter Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-04-18 23:50:13 +02:00
SLOT(fcntl, __sys_fcntl),
Fix known issues which blow up the process after dlopen("libthr.so") (or loading a dso linked to libthr.so into process which was not linked against threading library). - Remove libthr interposers of the libc functions, including __error(). Instead, functions calls are indirected through the interposing table, similar to how pthread stubs in libc are already done. Libc by default points either to syscall trampolines or to existing libc implementations. On libthr load, libthr rewrites the pointers to the cancellable implementations already in libthr. The interposition table is separate from pthreads stubs indirection table to not pull pthreads stubs into static binaries. - Postpone the malloc(3) internal mutexes initialization until libthr is loaded. This avoids recursion between calloc(3) and static pthread_mutex_t initialization. - Reinstall signal handlers with wrapper on libthr load. The _rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2) when libthr is statically referenced from the main binary. In the process, fix openat(2), swapcontext(2) and setcontext(2) interposing. The libc symbols were exported at different versions than libthr interposers. Export both libc and libthr versions from libc now, with default set to the higher version from libthr. Remove unused and disconnected swapcontext(3) userspace implementation from libc/gen. No objections from: deischen Tested by: pho, antoine (exp-run) (previous versions) Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-01-03 19:38:46 +01:00
SLOT(fsync, __sys_fsync),
SLOT(fork, __sys_fork),
SLOT(msync, __sys_msync),
SLOT(nanosleep, __sys_nanosleep),
SLOT(openat, __sys_openat),
SLOT(poll, __sys_poll),
SLOT(pselect, __sys_pselect),
SLOT(read, __sys_read),
SLOT(readv, __sys_readv),
SLOT(recvfrom, __sys_recvfrom),
SLOT(recvmsg, __sys_recvmsg),
SLOT(select, __sys_select),
SLOT(sendmsg, __sys_sendmsg),
SLOT(sendto, __sys_sendto),
SLOT(setcontext, __sys_setcontext),
SLOT(sigaction, __sys_sigaction),
SLOT(sigprocmask, __sys_sigprocmask),
SLOT(sigsuspend, __sys_sigsuspend),
SLOT(sigwait, __libc_sigwait),
SLOT(sigtimedwait, __sys_sigtimedwait),
SLOT(sigwaitinfo, __sys_sigwaitinfo),
SLOT(swapcontext, __sys_swapcontext),
SLOT(wait4, __sys_wait4),
SLOT(write, __sys_write),
SLOT(writev, __sys_writev),
Make kevent(2) a cancellation point. Note that to cancel blocked kevent(2) call, changelist must be empty, since we cannot cancel a call which already made changes to the process state. And in reverse, call which only makes changes to the kqueue state, without waiting for an event, is not cancellable. This makes a natural usage model to migrate kqueue loop to support cancellation, where existing single kevent(2) call must be split into two: first uncancellable update of kqueue, then cancellable wait for events. Note that this is ABI-incompatible change, but it is believed that there is no cancel-safe code that relies on kevent(2) not being a cancellation point. Option to preserve the ABI would be to keep kevent(2) as is, but add new call with flags to specify cancellation behaviour, which only value seems to add complications. Suggested and reviewed by: jilles Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
2015-03-29 21:14:41 +02:00
SLOT(kevent, __sys_kevent),
Make wait6(2), waitid(3) and ppoll(2) cancellation points. The waitid() function is required to be cancellable by the standard. The wait6() and ppoll() follow the other syscalls in their groups. Reviewed by: jhb, jilles (previous versions) Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-04-18 23:35:41 +02:00
SLOT(wait6, __sys_wait6),
SLOT(ppoll, __sys_ppoll),
The fdatasync(2) call must be cancellation point. Sponsored by: The FreeBSD Foundation MFC after: 13 days
2016-08-16 10:27:03 +02:00
SLOT(fdatasync, __sys_fdatasync),
Add clock_nanosleep() Add a clock_nanosleep() syscall, as specified by POSIX. Make nanosleep() a wrapper around it. Attach the clock_nanosleep test from NetBSD. Adjust it for the FreeBSD behavior of updating rmtp only when interrupted by a signal. I believe this to be POSIX-compliant, since POSIX mentions the rmtp parameter only in the paragraph about EINTR. This is also what Linux does. (NetBSD updates rmtp unconditionally.) Copy the whole nanosleep.2 man page from NetBSD because it is complete and closely resembles the POSIX description. Edit, polish, and reword it a bit, being sure to keep any relevant text from the FreeBSD page. Reviewed by: kib, ngie, jilles MFC after: 3 weeks Relnotes: yes Sponsored by: Dell EMC Differential Revision: https://reviews.freebsd.org/D10020
2017-03-19 01:51:12 +01:00
SLOT(clock_nanosleep, __sys_clock_nanosleep),
libthr: wrap pdfork(2), same as fork(2). Without wrapping, rtld services and malloc(3) are not guaranteed to operate correctly in the forked child. Reviewed by: markj MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D28088
2021-01-10 20:22:49 +01:00
SLOT(pdfork, __sys_pdfork),
Fix known issues which blow up the process after dlopen("libthr.so") (or loading a dso linked to libthr.so into process which was not linked against threading library). - Remove libthr interposers of the libc functions, including __error(). Instead, functions calls are indirected through the interposing table, similar to how pthread stubs in libc are already done. Libc by default points either to syscall trampolines or to existing libc implementations. On libthr load, libthr rewrites the pointers to the cancellable implementations already in libthr. The interposition table is separate from pthreads stubs indirection table to not pull pthreads stubs into static binaries. - Postpone the malloc(3) internal mutexes initialization until libthr is loaded. This avoids recursion between calloc(3) and static pthread_mutex_t initialization. - Reinstall signal handlers with wrapper on libthr load. The _rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2) when libthr is statically referenced from the main binary. In the process, fix openat(2), swapcontext(2) and setcontext(2) interposing. The libc symbols were exported at different versions than libthr interposers. Export both libc and libthr versions from libc now, with default set to the higher version from libthr. Remove unused and disconnected swapcontext(3) userspace implementation from libc/gen. No objections from: deischen Tested by: pho, antoine (exp-run) (previous versions) Sponsored by: The FreeBSD Foundation MFC after: 1 week
2015-01-03 19:38:46 +01:00
};
#undef SLOT
libc: split libc and syscall interposing (1/2) System calls or their wrappers are now interposed by __libsys_interposing with purely libc entries remaining in __libc_interposing. Use __libsys_interposing_slot in libthr to update __libsys_interposing, but also make __libc_interposing_slot fall back to __libsys_interposing_slot so an out of date libc has a chance of working during updates. Reviewed by: kib, emaste, imp Pull Request: https://github.com/freebsd/freebsd-src/pull/908
2024-01-16 21:16:39 +01:00
interpos_func_t *
__libsys_interposing_slot(int interposno)
{
return (&__libsys_interposing[interposno]);
}
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