popen modifies its file handler book-keeping under a lock that wasn't
being taken during fork. This meant that a concurrent popen and fork
could end up copying the lock in a "locked" state into the fork child,
where subsequently calling popen would lead to a deadlock due to the
already (spuriously) held lock.
This commit fixes the deadlock by appropriately taking the lock before
fork, and releasing/resetting it in the parent/child after the fork.
A new test for concurrent popen and fork is also added. It consistently
hangs (and therefore fails via timeout) without the fix applied.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The recursive lock used on abort does not synchronize with a new process
creation (either by fork-like interfaces or posix_spawn ones), nor it
is reinitialized after fork().
Also, the SIGABRT unblock before raise() shows another race condition,
where a fork or posix_spawn() call by another thread, just after the
recursive lock release and before the SIGABRT signal, might create
programs with a non-expected signal mask. With the default option
(without POSIX_SPAWN_SETSIGDEF), the process can see SIG_DFL for
SIGABRT, where it should be SIG_IGN.
To fix the AS-safe, raise() does not change the process signal mask,
and an AS-safe lock is used if a SIGABRT is installed or the process
is blocked or ignored. With the signal mask change removal,
there is no need to use a recursive loc. The lock is also taken on
both _Fork() and posix_spawn(), to avoid the spawn process to see the
abort handler as SIG_DFL.
A read-write lock is used to avoid serialize _Fork and posix_spawn
execution. Both sigaction (SIGABRT) and abort() requires to lock
as writer (since both change the disposition).
The fallback is also simplified: there is no need to use a loop of
ABORT_INSTRUCTION after _exit() (if the syscall does not terminate the
process, the system is broken).
The proposed fix changes how setjmp works on a SIGABRT handler, where
glibc does not save the signal mask. So usage like the below will now
always abort.
static volatile int chk_fail_ok;
static jmp_buf chk_fail_buf;
static void
handler (int sig)
{
if (chk_fail_ok)
{
chk_fail_ok = 0;
longjmp (chk_fail_buf, 1);
}
else
_exit (127);
}
[...]
signal (SIGABRT, handler);
[....]
chk_fail_ok = 1;
if (! setjmp (chk_fail_buf))
{
// Something that can calls abort, like a failed fortify function.
chk_fail_ok = 0;
printf ("FAIL\n");
}
Such cases will need to use sigsetjmp instead.
The _dl_start_profile calls sigaction through _profil, and to avoid
pulling abort() on loader the call is replaced with __libc_sigaction.
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: DJ Delorie <dj@redhat.com>
Macros will automatically use the correct types, without
having to fiddle with internal glibc macros. It's also
impossible to get the types wrong due to aliasing because
support_check_stat_fd and support_check_stat_path do not
depend on the struct stat* types.
The changes reveal some inconsistencies in tests.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Remove local FAIL macro in favor to FAIL_RET from <support/check.h>,
which provides equivalent reporting, with the name of the file of the
failure site additionally included, for the tst-truncate-common core
shared between the tst-truncate and tst-truncate64 tests.
Reviewed-by: DJ Delorie <dj@redhat.com>
The conditionals for several mtrace-based tests in catgets, elf, libio,
malloc, misc, nptl, posix, and stdio-common were incorrect leading to
test failures when bootstrapping glibc without perl.
The correct conditional for mtrace-based tests requires three checks:
first checking for run-built-tests, then build-shared, and lastly that
PERL is not equal to "no" (missing perl).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
If the pidfd_spawn/pidfd_spawnp helper process succeeds, but evecve
fails for some reason (either with an invalid/non-existent, memory
allocation, etc.) the resulting pidfd is never closed, nor returned
to caller (so it can call close).
Since the process creation failed, it should be up to posix_spawn to
also, close the file descriptor in this case (similar to what it
does to reap the process).
This patch also changes the waitpid with waitid (P_PIDFD) for pidfd
case, to avoid a possible pid re-use.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
These are required by the upcoming POSIX standard and are available on
other platforms.
Link: https://austingroupbugs.net/view.php?id=339
Signed-off-by: Mohamed Akram <mohd.akram@outlook.com>
Reviewed-by: Arjun Shankar <arjun@redhat.com>
It was raised on libc-help [1] that some Linux kernel interfaces expect
the libc to define __USE_TIME_BITS64 to indicate the time_t size for the
kABI. Different than defined by the initial y2038 design document [2],
the __USE_TIME_BITS64 is only defined for ABIs that support more than
one time_t size (by defining the _TIME_BITS for each module).
The 64 bit time_t redirects are now enabled using a different internal
define (__USE_TIME64_REDIRECTS). There is no expected change in semantic
or code generation.
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
arm-linux-gnueabi
[1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html
[2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign
Reviewed-by: DJ Delorie <dj@redhat.com>
It improve fortify checks for read, pread, pread64, readlink,
readlinkat, getcwd, getwd, confstr, getgroups, ttyname_r, getlogin_r,
gethostname, and getdomainname. The compile and runtime checks have
similar coverage as with GCC.
Checked on aarch64, armhf, x86_64, and i686.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
* posix/regex.c: [!_LIBC && __GNUC_PREREQ (4, 3)]:
Omit GCC pragmas no longer needed when this file is used as part of Gnulib.
-Wold-style-definition no longer needs to be ignored because the regex
code no longer uses old style definitions. -Wtype-limits no longer
needs to be ignored because Gnulib already arranges for it to be
ignored in the C compiler flags. This patch is taken from Gnulib.
I've updated copyright dates in glibc for 2024. This is the patch for
the changes not generated by scripts/update-copyrights and subsequent
build / regeneration of generated files.
Many applications still rely on this prototype. Rebuilds without
this prototype result in an implicit function declaration, which can
introduce security vulnerabilities due to 32-bit pointer truncation.
All the crypt related functions, cryptographic algorithms, and
make requirements are removed, with only the exception of md5
implementation which is moved to locale folder since it is
required by localedef for integrity protection (libc's
locale-reading code does not check these, but localedef does
generate them).
Besides thec code itself, both internal documentation and the
manual is also adjusted. This allows to remove both --enable-crypt
and --enable-nss-crypt configure options.
Checked with a build for all affected ABIs.
Co-authored-by: Zack Weinberg <zack@owlfolio.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
getnameinfo is an entry points for nss functionality. This commit moves
it from the 'inet' subdirectory to 'nss'. The corresponding Versions
entry is also moved from 'posix' into 'nss'.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
getaddrinfo is an entry point for nss functionality. This commit moves
it from 'sysdeps/posix' to 'nss', gets rid of the stub in 'posix', and
moves all associated tests as well.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The majority of grp routines are entry points for nss functionality.
This commit removes the 'grp' subdirectory and moves all nss-relevant
functionality and all tests to 'nss', and the 'setgroups' stub into
'posix' (alongside the 'getgroups' stub). References to grp/ are
accordingly changed. In addition, compat-initgroups.c, a fallback
implementation of initgroups is renamed to initgroups-fallback.c so that
the build system does not confuse it for nss_compat/compat-initgroups.c.
Build time improves very slightly; e.g. down from an average of 45.5s to
44.5s on an 8-thread mobile x86_64 CPU.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
getaddrinfo doesn't look for any RESOLVER defines for conditional
compilation. Therefore, remove the unnecessary -DRESOLVER build flag in
getaddrinfo's CFLAGS.
Checked on x86_64 for code generation changes; none found.
Returning a pidfd allows a process to keep a race-free handle for a
child process, otherwise, the caller will need to either use pidfd_open
(which still might be subject to TOCTOU) or keep the old racy interface
base on pid_t.
To correct use pifd_spawn, the kernel must support not only returning
the pidfd with clone/clone3 but also waitid (P_PIDFD) (added on Linux
5.4). If kernel does not support the waitid, pidfd return ENOSYS.
It avoids the need to racy workarounds, such as reading the procfs
fdinfo to get the pid to use along with other wait interfaces.
These interfaces are similar to the posix_spawn and posix_spawnp, with
the only difference being it returns a process file descriptor (int)
instead of a process ID (pid_t). Their prototypes are:
int pidfd_spawn (int *restrict pidfd,
const char *restrict file,
const posix_spawn_file_actions_t *restrict facts,
const posix_spawnattr_t *restrict attrp,
char *const argv[restrict],
char *const envp[restrict])
int pidfd_spawnp (int *restrict pidfd,
const char *restrict path,
const posix_spawn_file_actions_t *restrict facts,
const posix_spawnattr_t *restrict attrp,
char *const argv[restrict_arr],
char *const envp[restrict_arr]);
A new symbol is used instead of a posix_spawn extension to avoid
possible issues with language bindings that might track the return
argument lifetime. Although on Linux pid_t and int are interchangeable,
POSIX only states that pid_t should be a signed integer.
Both symbols reuse the posix_spawn posix_spawn_file_actions_t and
posix_spawnattr_t, to void rehash posix_spawn API or add a new one. It
also means that both interfaces support the same attribute and file
actions, and a new flag or file action on posix_spawn is also added
automatically for pidfd_spawn.
Also, using posix_spawn plumbing allows the reusing of most of the
current testing with some changes:
- waitid is used instead of waitpid since it is a more generic
interface.
- tst-posix_spawn-setsid.c is adapted to take into consideration that
the caller can check for session id directly. The test now spawns
itself and writes the session id as a file instead.
- tst-spawn3.c need to know where pidfd_spawn is used so it keeps an
extra file description unused.
Checked on x86_64-linux-gnu on Linux 4.15 (no CLONE_PIDFD or waitid
support), Linux 5.4 (full support), and Linux 6.2.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
These functions allow to posix_spawn and posix_spawnp to use
CLONE_INTO_CGROUP with clone3, allowing the child process to
be created in a different cgroup version 2. These are GNU
extensions that are available only for Linux, and also only
for the architectures that implement clone3 wrapper
(HAVE_CLONE3_WRAPPER).
To create a process on a different cgroupv2, one can use the:
posix_spawnattr_t attr;
posix_spawnattr_init (&attr);
posix_spawnattr_setflags (&attr, POSIX_SPAWN_SETCGROUP);
posix_spawnattr_setcgroup_np (&attr, cgroup);
posix_spawn (...)
Similar to other posix_spawn flags, POSIX_SPAWN_SETCGROUP control
whether the cgroup file descriptor will be used or not with
clone3.
There is no fallback if either clone3 does not support the flag
or if the architecture does not provide the clone3 wrapper, in
this case posix_spawn returns EOPNOTSUPP.
Checked on x86_64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Posix says that d_name is of unspecified size, and sizeof(d_name)
should not be used. It is indeed only 1-byte long in bits/dirent.h. We
can instead explictly provide the actual allocated size to
__strcpy_chk.
With gcc 11.3.1, building with -D_FORTIFY_SOURCE=2 shows:
In function ‘getgroups’,
inlined from ‘do_test’ at test-errno.c:129:12:
../misc/sys/cdefs.h:195:6: error: argument 1 value -1 is negative
[-Werror=stringop-overflow=]
195 | ? __ ## f ## _alias (__VA_ARGS__)
\
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../posix/bits/unistd.h:115:10: note: in expansion of macro
‘__glibc_fortify’
115 | return __glibc_fortify (getgroups, __size, sizeof (__gid_t),
| ^~~~~~~~~~~~~~~
../posix/bits/unistd.h: In function ‘do_test’:
../posix/bits/unistd-decl.h:135:28: note: in a call to function
‘__getgroups_alias’ declared with attribute ‘access (write_only, 2, 1)’
135 | extern int __REDIRECT_NTH (__getgroups_alias, (int __size,
__gid_t __list[]),
| ^~~~~~~~~~~~~~~~~
../misc/sys/cdefs.h:264:6: note: in definition of macro ‘__REDIRECT_NTH’
264 | name proto __asm__ (__ASMNAME (#alias)) __THROW
It builds fine with gcc 12 and gcc 13.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The change is meant to avoid unwanted PLT entries for the read_chk,
getdomainname_chk and getlogin_r_chk routines when _FORTIFY_SOURCE is set.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
This change is similar to what was done for bits/wchar2.h.
Routines declaration are moved into a dedicated bits/unistd-decl.h file
which is then included into the bits/unistd.h file.
This will allow to adapt the files so that PLT entries are not created when
_FORTIFY_SOURCE is enabled.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Since the _FORTIFY_SOURCE feature uses some routines of Glibc, they need to
be excluded from the fortification.
On top of that:
- some tests explicitly verify that some level of fortification works
appropriately, we therefore shouldn't modify the level set for them.
- some objects need to be build with optimization disabled, which
prevents _FORTIFY_SOURCE to be used for them.
Assembler files that implement architecture specific versions of the
fortified routines were not excluded from _FORTIFY_SOURCE as there is no
C header included that would impact their behavior.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
In documentation, call strings like "CST" time zone abbreviations, not
time zone names. This terminology is more precise, and is what tzdb uses.
A string like "CST" is ambiguous and does not fully name a time zone.
With fortification enabled, few function calls return result need to be
checked, has they get the __wur macro enabled.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
When enabling _FORTIFY_SOURCE, some functions now lead to warnings when
their result is not checked.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
With fortification enabled, few function calls return result need to be
checked, has they get the __wur macro enabled.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
With fortification enabled, ftruncate calls return result needs to be
checked, has it gets the __wur macro enabled.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Fix LOCALE list formatting.
Sort all reflowed text using scripts/sort-makefile-lines.py.
No code generation changes observed in binary artifacts.
No regressions on x86_64 and i686.
include/regex.h had not been updated during the int -> Idx transition,
and the prototypes don't matched the definitions in regexec.c.
In regcomp.c, most interfaces were updated for Idx, except for two ones
guarded by #if _LIBC.
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Without these fixes, the first three included tests segfault (on a
NULL dereference); the fourth aborts on an assertion, which is itself
unnecessary.
Signed-off-by: Julian Squires <julian@cipht.net>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
They are both used by __libc_freeres to free all library malloc
allocated resources to help tooling like mtrace or valgrind with
memory leak tracking.
The current scheme uses assembly markers and linker script entries
to consolidate the free routine function pointers in the RELRO segment
and to be freed buffers in BSS.
This patch changes it to use specific free functions for
libc_freeres_ptrs buffers and call the function pointer array directly
with call_function_static_weak.
It allows the removal of both the internal macros and the linker
script sections.
Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
according to man-pages-posix-2017, shm_open() function may fail if the length
of the name argument exceeds {_POSIX_PATH_MAX} and set ENAMETOOLONG
Signed-off-by: abushwang <abushwangs@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To avoid possible failure if any parent set any initial signal
disposition as SIG_IGN (for instance if the testcase is issued
with nohup).
Checked on x86_64-linux-gnu.
Tested-by: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
ISO C does not support omitting parameter names in function definitions
before C2X,the compiler is giving an error with older versions of gcc and
this commit will resolve the test failure "error: parameter name omitted"
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This adds a special SHM_ANON value that can be passed into shm_open ()
in place of a name. When called in this way, shm_open () will create a
new anonymous shared memory file. The file will be created in the same
way that other shared memory files are created (i.e., under /dev/shm/),
except that it is not given a name and therefore cannot be reached from
the file system, nor by other calls to shm_open (). This is accomplished
by utilizing O_TMPFILE.
This is intended to be compatible with FreeBSD's API of the same name.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
Message-Id: <20230130125216.6254-4-bugaevc@gmail.com>
The clone3 flag resets all signal handlers of the child not set to
SIG_IGN to SIG_DFL. It allows to skip most of the sigaction calls
to setup child signal handling, where previously a posix_spawn
had to issue 2 times NSIG sigaction calls (one to obtain the current
disposition and another to set either SIG_DFL or SIG_IGN).
With POSIX_SPAWN_SETSIGDEF the child will setup the signal for the case
where the disposition is SIG_IGN.
The code must handle the fallback where clone3 is not available. This is
done by splitting __clone_internal_fallback from __clone_internal.
Checked on x86_64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
I've updated copyright dates in glibc for 2023. This is the patch for
the changes not generated by scripts/update-copyrights and subsequent
build / regeneration of generated files.
Some sources merely include <spawn.h> without -D_GNU_SOURCE and expect
declarations for posix_spawn_file_actions_addchdir_np to be available.
For consistency, declare posix_spawn_file_actions_addfchdir_np,
posix_spawn_file_actions_addclosefrom_np,
posix_spawn_file_actions_addtcsetpgrp_np as well.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
clang emits an warning when a double alias redirection is used, to warn
the the original symbol will be used even when weak definition is
overridden. However, this is a common pattern for weak_alias, where
multiple alias are set to same symbol.
Reviewed-by: Fangrui Song <maskray@google.com>
