@@ -47,6 +47,7 @@ routines = \
lowlevellock \
nptl_deallocate_tsd \
nptl_nthreads \
+ nptl_setxid \
old_pthread_cond_broadcast \
old_pthread_cond_destroy \
old_pthread_cond_init \
@@ -147,6 +147,7 @@ libc {
__mutex_aconf;
__nptl_deallocate_tsd;
__nptl_nthreads;
+ __nptl_setxid_sighandler;
__pthread_attr_copy;
__pthread_attr_destroy;
__pthread_attr_init;
@@ -953,215 +953,6 @@ __reclaim_stacks (void)
}
-static void
-setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
-{
- int ch;
-
- /* Wait until this thread is cloned. */
- if (t->setxid_futex == -1
- && ! atomic_compare_and_exchange_bool_acq (&t->setxid_futex, -2, -1))
- do
- futex_wait_simple (&t->setxid_futex, -2, FUTEX_PRIVATE);
- while (t->setxid_futex == -2);
-
- /* Don't let the thread exit before the setxid handler runs. */
- t->setxid_futex = 0;
-
- do
- {
- ch = t->cancelhandling;
-
- /* If the thread is exiting right now, ignore it. */
- if ((ch & EXITING_BITMASK) != 0)
- {
- /* Release the futex if there is no other setxid in
- progress. */
- if ((ch & SETXID_BITMASK) == 0)
- {
- t->setxid_futex = 1;
- futex_wake (&t->setxid_futex, 1, FUTEX_PRIVATE);
- }
- return;
- }
- }
- while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
- ch | SETXID_BITMASK, ch));
-}
-
-
-static void
-setxid_unmark_thread (struct xid_command *cmdp, struct pthread *t)
-{
- int ch;
-
- do
- {
- ch = t->cancelhandling;
- if ((ch & SETXID_BITMASK) == 0)
- return;
- }
- while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
- ch & ~SETXID_BITMASK, ch));
-
- /* Release the futex just in case. */
- t->setxid_futex = 1;
- futex_wake (&t->setxid_futex, 1, FUTEX_PRIVATE);
-}
-
-
-static int
-setxid_signal_thread (struct xid_command *cmdp, struct pthread *t)
-{
- if ((t->cancelhandling & SETXID_BITMASK) == 0)
- return 0;
-
- int val;
- pid_t pid = __getpid ();
- val = INTERNAL_SYSCALL_CALL (tgkill, pid, t->tid, SIGSETXID);
-
- /* If this failed, it must have had not started yet or else exited. */
- if (!INTERNAL_SYSCALL_ERROR_P (val))
- {
- atomic_increment (&cmdp->cntr);
- return 1;
- }
- else
- return 0;
-}
-
-/* Check for consistency across set*id system call results. The abort
- should not happen as long as all privileges changes happen through
- the glibc wrappers. ERROR must be 0 (no error) or an errno
- code. */
-void
-attribute_hidden
-__nptl_setxid_error (struct xid_command *cmdp, int error)
-{
- do
- {
- int olderror = cmdp->error;
- if (olderror == error)
- break;
- if (olderror != -1)
- {
- /* Mismatch between current and previous results. Save the
- error value to memory so that is not clobbered by the
- abort function and preserved in coredumps. */
- volatile int xid_err __attribute__((unused)) = error;
- abort ();
- }
- }
- while (atomic_compare_and_exchange_bool_acq (&cmdp->error, error, -1));
-}
-
-int
-attribute_hidden
-__nptl_setxid (struct xid_command *cmdp)
-{
- int signalled;
- int result;
- lll_lock (GL (dl_stack_cache_lock), LLL_PRIVATE);
-
- __xidcmd = cmdp;
- cmdp->cntr = 0;
- cmdp->error = -1;
-
- struct pthread *self = THREAD_SELF;
-
- /* Iterate over the list with system-allocated threads first. */
- list_t *runp;
- list_for_each (runp, &GL (dl_stack_used))
- {
- struct pthread *t = list_entry (runp, struct pthread, list);
- if (t == self)
- continue;
-
- setxid_mark_thread (cmdp, t);
- }
-
- /* Now the list with threads using user-allocated stacks. */
- list_for_each (runp, &GL (dl_stack_user))
- {
- struct pthread *t = list_entry (runp, struct pthread, list);
- if (t == self)
- continue;
-
- setxid_mark_thread (cmdp, t);
- }
-
- /* Iterate until we don't succeed in signalling anyone. That means
- we have gotten all running threads, and their children will be
- automatically correct once started. */
- do
- {
- signalled = 0;
-
- list_for_each (runp, &GL (dl_stack_used))
- {
- struct pthread *t = list_entry (runp, struct pthread, list);
- if (t == self)
- continue;
-
- signalled += setxid_signal_thread (cmdp, t);
- }
-
- list_for_each (runp, &GL (dl_stack_user))
- {
- struct pthread *t = list_entry (runp, struct pthread, list);
- if (t == self)
- continue;
-
- signalled += setxid_signal_thread (cmdp, t);
- }
-
- int cur = cmdp->cntr;
- while (cur != 0)
- {
- futex_wait_simple ((unsigned int *) &cmdp->cntr, cur,
- FUTEX_PRIVATE);
- cur = cmdp->cntr;
- }
- }
- while (signalled != 0);
-
- /* Clean up flags, so that no thread blocks during exit waiting
- for a signal which will never come. */
- list_for_each (runp, &GL (dl_stack_used))
- {
- struct pthread *t = list_entry (runp, struct pthread, list);
- if (t == self)
- continue;
-
- setxid_unmark_thread (cmdp, t);
- }
-
- list_for_each (runp, &GL (dl_stack_user))
- {
- struct pthread *t = list_entry (runp, struct pthread, list);
- if (t == self)
- continue;
-
- setxid_unmark_thread (cmdp, t);
- }
-
- /* This must be last, otherwise the current thread might not have
- permissions to send SIGSETXID syscall to the other threads. */
- result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, 3,
- cmdp->id[0], cmdp->id[1], cmdp->id[2]);
- int error = 0;
- if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result)))
- {
- error = INTERNAL_SYSCALL_ERRNO (result);
- __set_errno (error);
- result = -1;
- }
- __nptl_setxid_error (cmdp, error);
-
- lll_unlock (GL (dl_stack_cache_lock), LLL_PRIVATE);
- return result;
-}
-
static inline void __attribute__((always_inline))
init_one_static_tls (struct pthread *curp, struct link_map *map)
{
@@ -52,7 +52,6 @@ static const char nptl_version[] __attribute_used__ = VERSION;
#ifdef SHARED
static const struct pthread_functions pthread_functions =
{
- .ptr__nptl_setxid = __nptl_setxid,
};
# define ptr_pthread_functions &pthread_functions
#else
@@ -106,52 +105,6 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx)
}
-struct xid_command *__xidcmd attribute_hidden;
-
-/* We use the SIGSETXID signal in the setuid, setgid, etc. implementations to
- tell each thread to call the respective setxid syscall on itself. This is
- the handler. */
-static void
-sighandler_setxid (int sig, siginfo_t *si, void *ctx)
-{
- int result;
-
- /* Safety check. It would be possible to call this function for
- other signals and send a signal from another process. This is not
- correct and might even be a security problem. Try to catch as
- many incorrect invocations as possible. */
- if (sig != SIGSETXID
- || si->si_pid != __getpid ()
- || si->si_code != SI_TKILL)
- return;
-
- result = INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, 3, __xidcmd->id[0],
- __xidcmd->id[1], __xidcmd->id[2]);
- int error = 0;
- if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result)))
- error = INTERNAL_SYSCALL_ERRNO (result);
- __nptl_setxid_error (__xidcmd, error);
-
- /* Reset the SETXID flag. */
- struct pthread *self = THREAD_SELF;
- int flags, newval;
- do
- {
- flags = THREAD_GETMEM (self, cancelhandling);
- newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
- flags & ~SETXID_BITMASK, flags);
- }
- while (flags != newval);
-
- /* And release the futex. */
- self->setxid_futex = 1;
- futex_wake (&self->setxid_futex, 1, FUTEX_PRIVATE);
-
- if (atomic_decrement_val (&__xidcmd->cntr) == 0)
- futex_wake ((unsigned int *) &__xidcmd->cntr, 1, FUTEX_PRIVATE);
-}
-
-
/* When using __thread for this, we do it in libc so as not
to give libpthread its own TLS segment just for this. */
extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
@@ -183,7 +136,7 @@ __pthread_initialize_minimal_internal (void)
(void) __libc_sigaction (SIGCANCEL, &sa, NULL);
/* Install the handle to change the threads' uid/gid. */
- sa.sa_sigaction = sighandler_setxid;
+ sa.sa_sigaction = __nptl_setxid_sighandler;
sa.sa_flags = SA_SIGINFO | SA_RESTART;
(void) __libc_sigaction (SIGSETXID, &sa, NULL);
new file mode 100644
@@ -0,0 +1,279 @@
+/* Copyright (C) 2002-2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <futex-internal.h>
+#include <ldsodefs.h>
+#include <list.h>
+#include <lowlevellock.h>
+#include <pthreadP.h>
+#include <unistd.h>
+
+/* Check for consistency across set*id system call results. The abort
+ should not happen as long as all privileges changes happen through
+ the glibc wrappers. ERROR must be 0 (no error) or an errno
+ code. */
+static void
+setxid_error (struct xid_command *cmdp, int error)
+{
+ do
+ {
+ int olderror = cmdp->error;
+ if (olderror == error)
+ break;
+ if (olderror != -1)
+ {
+ /* Mismatch between current and previous results. Save the
+ error value to memory so that is not clobbered by the
+ abort function and preserved in coredumps. */
+ volatile int xid_err __attribute__ ((unused)) = error;
+ abort ();
+ }
+ }
+ while (atomic_compare_and_exchange_bool_acq (&cmdp->error, error, -1));
+}
+
+/* Set by __nptl_setxid and used by __nptl_setxid_sighandler. */
+static struct xid_command *xidcmd;
+
+/* We use the SIGSETXID signal in the setuid, setgid, etc. implementations to
+ tell each thread to call the respective setxid syscall on itself. This is
+ the handler. */
+void
+__nptl_setxid_sighandler (int sig, siginfo_t *si, void *ctx)
+{
+ int result;
+
+ /* Safety check. It would be possible to call this function for
+ other signals and send a signal from another process. This is not
+ correct and might even be a security problem. Try to catch as
+ many incorrect invocations as possible. */
+ if (sig != SIGSETXID
+ || si->si_pid != __getpid ()
+ || si->si_code != SI_TKILL)
+ return;
+
+ result = INTERNAL_SYSCALL_NCS (xidcmd->syscall_no, 3, xidcmd->id[0],
+ xidcmd->id[1], xidcmd->id[2]);
+ int error = 0;
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result)))
+ error = INTERNAL_SYSCALL_ERRNO (result);
+ setxid_error (xidcmd, error);
+
+ /* Reset the SETXID flag. */
+ struct pthread *self = THREAD_SELF;
+ int flags, newval;
+ do
+ {
+ flags = THREAD_GETMEM (self, cancelhandling);
+ newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
+ flags & ~SETXID_BITMASK, flags);
+ }
+ while (flags != newval);
+
+ /* And release the futex. */
+ self->setxid_futex = 1;
+ futex_wake (&self->setxid_futex, 1, FUTEX_PRIVATE);
+
+ if (atomic_decrement_val (&xidcmd->cntr) == 0)
+ futex_wake ((unsigned int *) &xidcmd->cntr, 1, FUTEX_PRIVATE);
+}
+libc_hidden_def (__nptl_setxid_sighandler)
+
+static void
+setxid_mark_thread (struct xid_command *cmdp, struct pthread *t)
+{
+ int ch;
+
+ /* Wait until this thread is cloned. */
+ if (t->setxid_futex == -1
+ && ! atomic_compare_and_exchange_bool_acq (&t->setxid_futex, -2, -1))
+ do
+ futex_wait_simple (&t->setxid_futex, -2, FUTEX_PRIVATE);
+ while (t->setxid_futex == -2);
+
+ /* Don't let the thread exit before the setxid handler runs. */
+ t->setxid_futex = 0;
+
+ do
+ {
+ ch = t->cancelhandling;
+
+ /* If the thread is exiting right now, ignore it. */
+ if ((ch & EXITING_BITMASK) != 0)
+ {
+ /* Release the futex if there is no other setxid in
+ progress. */
+ if ((ch & SETXID_BITMASK) == 0)
+ {
+ t->setxid_futex = 1;
+ futex_wake (&t->setxid_futex, 1, FUTEX_PRIVATE);
+ }
+ return;
+ }
+ }
+ while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
+ ch | SETXID_BITMASK, ch));
+}
+
+
+static void
+setxid_unmark_thread (struct xid_command *cmdp, struct pthread *t)
+{
+ int ch;
+
+ do
+ {
+ ch = t->cancelhandling;
+ if ((ch & SETXID_BITMASK) == 0)
+ return;
+ }
+ while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling,
+ ch & ~SETXID_BITMASK, ch));
+
+ /* Release the futex just in case. */
+ t->setxid_futex = 1;
+ futex_wake (&t->setxid_futex, 1, FUTEX_PRIVATE);
+}
+
+
+static int
+setxid_signal_thread (struct xid_command *cmdp, struct pthread *t)
+{
+ if ((t->cancelhandling & SETXID_BITMASK) == 0)
+ return 0;
+
+ int val;
+ pid_t pid = __getpid ();
+ val = INTERNAL_SYSCALL_CALL (tgkill, pid, t->tid, SIGSETXID);
+
+ /* If this failed, it must have had not started yet or else exited. */
+ if (!INTERNAL_SYSCALL_ERROR_P (val))
+ {
+ atomic_increment (&cmdp->cntr);
+ return 1;
+ }
+ else
+ return 0;
+}
+
+int
+attribute_hidden
+__nptl_setxid (struct xid_command *cmdp)
+{
+ int signalled;
+ int result;
+ lll_lock (GL (dl_stack_cache_lock), LLL_PRIVATE);
+
+ xidcmd = cmdp;
+ cmdp->cntr = 0;
+ cmdp->error = -1;
+
+ struct pthread *self = THREAD_SELF;
+
+ /* Iterate over the list with system-allocated threads first. */
+ list_t *runp;
+ list_for_each (runp, &GL (dl_stack_used))
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ setxid_mark_thread (cmdp, t);
+ }
+
+ /* Now the list with threads using user-allocated stacks. */
+ list_for_each (runp, &GL (dl_stack_user))
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ setxid_mark_thread (cmdp, t);
+ }
+
+ /* Iterate until we don't succeed in signalling anyone. That means
+ we have gotten all running threads, and their children will be
+ automatically correct once started. */
+ do
+ {
+ signalled = 0;
+
+ list_for_each (runp, &GL (dl_stack_used))
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ signalled += setxid_signal_thread (cmdp, t);
+ }
+
+ list_for_each (runp, &GL (dl_stack_user))
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ signalled += setxid_signal_thread (cmdp, t);
+ }
+
+ int cur = cmdp->cntr;
+ while (cur != 0)
+ {
+ futex_wait_simple ((unsigned int *) &cmdp->cntr, cur,
+ FUTEX_PRIVATE);
+ cur = cmdp->cntr;
+ }
+ }
+ while (signalled != 0);
+
+ /* Clean up flags, so that no thread blocks during exit waiting
+ for a signal which will never come. */
+ list_for_each (runp, &GL (dl_stack_used))
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ setxid_unmark_thread (cmdp, t);
+ }
+
+ list_for_each (runp, &GL (dl_stack_user))
+ {
+ struct pthread *t = list_entry (runp, struct pthread, list);
+ if (t == self)
+ continue;
+
+ setxid_unmark_thread (cmdp, t);
+ }
+
+ /* This must be last, otherwise the current thread might not have
+ permissions to send SIGSETXID syscall to the other threads. */
+ result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, 3,
+ cmdp->id[0], cmdp->id[1], cmdp->id[2]);
+ int error = 0;
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (result)))
+ {
+ error = INTERNAL_SYSCALL_ERRNO (result);
+ __set_errno (error);
+ result = -1;
+ }
+ setxid_error (cmdp, error);
+
+ lll_unlock (GL (dl_stack_cache_lock), LLL_PRIVATE);
+ return result;
+}
@@ -701,8 +701,8 @@ extern void _pthread_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer
extern void __nptl_deallocate_tsd (void);
libc_hidden_proto (__nptl_deallocate_tsd)
-extern void __nptl_setxid_error (struct xid_command *cmdp, int error)
- attribute_hidden;
+void __nptl_setxid_sighandler (int sig, siginfo_t *si, void *ctx);
+libc_hidden_proto (__nptl_setxid_sighandler)
extern int __nptl_setxid (struct xid_command *cmdp) attribute_hidden;
extern void __nptl_stacks_freeres (void) attribute_hidden;
@@ -30,7 +30,6 @@ struct xid_command;
the thread functions. */
struct pthread_functions
{
- int (*ptr__nptl_setxid) (struct xid_command *);
};
/* Variable in libc.so. */
@@ -16,6 +16,7 @@
<https://www.gnu.org/licenses/>. */
#include <nptl/pthreadP.h>
+#include <sys/single_threaded.h>
#include <sysdep.h>
#define __SETXID_1(cmd, arg1) \
@@ -25,30 +26,10 @@
#define __SETXID_3(cmd, arg1, arg2, arg3) \
__SETXID_2 (cmd, arg1, arg2); cmd.id[2] = (long int) arg3
-#ifdef SINGLE_THREAD
-# define INLINE_SETXID_SYSCALL(name, nr, args...) \
- INLINE_SYSCALL (name, nr, args)
-#elif defined SHARED
-# define INLINE_SETXID_SYSCALL(name, nr, args...) \
+#define INLINE_SETXID_SYSCALL(name, nr, args...) \
({ \
int __result; \
- if (__builtin_expect (__libc_pthread_functions_init, 0)) \
- { \
- struct xid_command __cmd; \
- __cmd.syscall_no = __NR_##name; \
- __SETXID_##nr (__cmd, args); \
- __result = PTHFCT_CALL (ptr__nptl_setxid, (&__cmd)); \
- } \
- else \
- __result = INLINE_SYSCALL (name, nr, args); \
- __result; \
- })
-#else
-# define INLINE_SETXID_SYSCALL(name, nr, args...) \
- ({ \
- extern __typeof (__nptl_setxid) __nptl_setxid __attribute__((weak));\
- int __result; \
- if (__glibc_unlikely (__nptl_setxid != NULL)) \
+ if (!__libc_single_threaded) \
{ \
struct xid_command __cmd; \
__cmd.syscall_no = __NR_##name; \
@@ -59,4 +40,3 @@
__result = INLINE_SYSCALL (name, nr, args); \
__result; \
})
-#endif
@@ -110,8 +110,4 @@ __libc_signal_restore_set (const sigset_t *set)
INTERNAL_SYSCALL_CALL (rt_sigprocmask, SIG_SETMASK, set, NULL,
__NSIG_BYTES);
}
-
-/* Used to communicate with signal handler. */
-extern struct xid_command *__xidcmd attribute_hidden;
-
#endif