The old BSD 4.4 definition (not used by Linux) was not 64b-proof: the
cmsg_data field is supposed to CMSG_ALIGN'ed (as can be also seen in the
CMSG_LEN macro).
Suggested-by: Diego Nieto Cid <dnietoc@gmail.com>
If some shared library loaded with dlopen/dlmopen requires an executable
stack, either implicitly because of a missing GNU_STACK ELF header
(where the ABI default flags implies in the executable bit) or explicitly
because of the executable bit from GNU_STACK; the loader will try to set
the both the main thread and all thread stacks (from the pthread cache)
as executable.
Besides the issue where any __nptl_change_stack_perm failure does not
undo the previous executable transition (meaning that if the library
fails to load, there can be thread stacks with executable stacks), this
behavior was used on a CVE [1] as a vector for RCE.
This patch changes that if a shared library requires an executable
stack, and the current stack is not executable, dlopen fails. The
change is done only for dynamically loaded modules, if the program
or any dependency requires an executable stack, the loader will still
change the main thread before program execution and any thread created
with default stack configuration.
[1] https://www.qualys.com/2023/07/19/cve-2023-38408/rce-openssh-forwarded-ssh-agent.txt
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
move out __getpid from pt-mutex.h
and in pt-mutex-* include <unistd.h> where
__getpid was called
Signed-off-by: gfleury <gfleury@disroot.org>
Message-ID: <20241219203727.669825-8-gfleury@disroot.org>
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the atan2pi functions (atan2(y,x)/pi).
Tested for x86_64 and x86, and with build-many-glibcs.py.
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the atanpi functions (atan(x)/pi).
Tested for x86_64 and x86, and with build-many-glibcs.py.
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the asinpi functions (asin(x)/pi).
Tested for x86_64 and x86, and with build-many-glibcs.py.
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the acospi functions (acos(x)/pi).
Tested for x86_64 and x86, and with build-many-glibcs.py.
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the tanpi functions (tan(pi*x)).
Tested for x86_64 and x86, and with build-many-glibcs.py.
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the sinpi functions (sin(pi*x)).
Tested for x86_64 and x86, and with build-many-glibcs.py.
C23 adds various <math.h> function families originally defined in TS
18661-4. Add the cospi functions (cos(pi*x)).
Tested for x86_64 and x86, and with build-many-glibcs.py.
Linux 6.11 has getrandom() in vDSO. It operates on a thread-local opaque
state allocated with mmap using flags specified by the vDSO.
Multiple states are allocated at once, as many as fit into a page, and
these are held in an array of available states to be doled out to each
thread upon first use, and recycled when a thread terminates. As these
states run low, more are allocated.
To make this procedure async-signal-safe, a simple guard is used in the
LSB of the opaque state address, falling back to the syscall if there's
reentrancy contention.
Also, _Fork() is handled by blocking signals on opaque state allocation
(so _Fork() always sees a consistent state even if it interrupts a
getrandom() call) and by iterating over the thread stack cache on
reclaim_stack. Each opaque state will be in the free states list
(grnd_alloc.states) or allocated to a running thread.
The cancellation is handled by always using GRND_NONBLOCK flags while
calling the vDSO, and falling back to the cancellable syscall if the
kernel returns EAGAIN (would block). Since getrandom is not defined by
POSIX and cancellation is supported as an extension, the cancellation is
handled as 'may occur' instead of 'shall occur' [1], meaning that if
vDSO does not block (the expected behavior) getrandom will not act as a
cancellation entrypoint. It avoids a pthread_testcancel call on the fast
path (different than 'shall occur' functions, like sem_wait()).
It is currently enabled for x86_64, which is available in Linux 6.11,
and aarch64, powerpc32, powerpc64, loongarch64, and s390x, which are
available in Linux 6.12.
Link: https://pubs.opengroup.org/onlinepubs/9799919799/nframe.html [1]
Co-developed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Jason A. Donenfeld <Jason@zx2c4.com> # x86_64
Tested-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> # x86_64, aarch64
Tested-by: Xi Ruoyao <xry111@xry111.site> # x86_64, aarch64, loongarch64
Tested-by: Stefan Liebler <stli@linux.ibm.com> # s390x
GCC mainline produces a -Wheader-guard error building for x86_64-gnu.
Fix what seems to be incorrect macro naming in the #ifndef
conditional.
Tested with build-many-glibc.py for x86_64-gnu (GCC mainline).
Message-ID: <fd800046-5ecb-ebd5-4df1-29d4eb3d5433@redhat.com>
A common use case of access () / faccessat () is checking for file
existence, not any specific access permissions. In that case, we can
avoid doing the file_check_access () RPC; whether the given path had
been successfully resolved to a file is all we need to know to answer.
This is prompted by GLib switching to use faccessat (F_OK) to implement
g_file_query_exists () for local files.
https://gitlab.gnome.org/GNOME/glib/-/merge_requests/4272
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-ID: <20240919101439.179663-1-bugaevc@gmail.com>
5476f8cd2e ("htl: move pthread_self info libc.") and
9dfa256216 ("htl: move pthread_equal into libc") to
1dc0bc8f07 ("htl: move pthread_attr_setdetachstate into libc")
moved some pthread_ symbols from libpthread.so to libc.so, but missed
adding the compat version like 5476f8cd2e ("htl: move pthread_self
info libc.") did: libc already had these symbols as forwards,
but versioned GLIBC_2.21, while the symbols in libpthread.so were
versioned GLIBC_2.12.
To fix running executables built before this, we thus have to add the
GLIBC_2.12 version, otherwise execution fails with e.g.
/usr/lib/i386-gnu/libglib-2.0.so: symbol lookup error: /usr/lib/i386-gnu/libglib-2.0.so: undefined symbol: pthread_attr_setinheritsched, version GLIBC_2.12
gfleury
Samuel Thibault
Paul Eggert
Adhemerval Zanella
Joseph Myers
Bruno Haible
Sergey Bugaev