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Disable rseq registration by default to help Firefox (#1855729)

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This commit is contained in:
Florian Weimer 2020-07-10 13:13:21 +02:00
parent 0aab7eb585
commit b633c425b5
2 changed files with 130 additions and 1 deletions
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125
glibc-rseq-disable.patch Normal file
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@ -0,0 +1,125 @@
Disable rseq integration until the Firefox sandbox supports rseq.
Sandbox is incompatible with rseq registration
<https://bugzilla.mozilla.org/show_bug.cgi?id=1651701>
diff --git a/elf/libc_early_init.c b/elf/libc_early_init.c
index 86da66d5e01af08f..fd779941e7180fb6 100644
--- a/elf/libc_early_init.c
+++ b/elf/libc_early_init.c
@@ -28,8 +28,9 @@ __libc_early_init (_Bool initial)
__ctype_init ();
/* Register rseq ABI to the kernel for the main program's libc. */
+ rseq_active_init ();
if (initial)
- rseq_register_current_thread ();
+ rseq_register_current_thread ();
/* Only the outer namespace is marked as single-threaded. */
__libc_single_threaded = initial;
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index f72741b7e5afb22a..a730077142f0e20a 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -171,6 +171,8 @@ libc {
__rseq_abi;
}
GLIBC_PRIVATE {
+ __rseq_active;
+
# functions used in other libraries
__syscall_rt_sigqueueinfo;
__open_nocancel;
diff --git a/sysdeps/unix/sysv/linux/rseq-internal.h b/sysdeps/unix/sysv/linux/rseq-internal.h
index 8f6772ca1deada89..acaf033be465facd 100644
--- a/sysdeps/unix/sysv/linux/rseq-internal.h
+++ b/sysdeps/unix/sysv/linux/rseq-internal.h
@@ -23,13 +23,29 @@
#include <kernel-features.h>
#include <stdio.h>
#include <sys/rseq.h>
+#include <unistd.h>
#ifdef RSEQ_SIG
+
+extern _Bool __rseq_active;
+
+static inline void
+rseq_active_init (void)
+{
+ __rseq_active = __access ("/etc/glibc.rseq.enabled", F_OK) == 0;
+}
+
static inline void
rseq_register_current_thread (void)
{
int ret;
+ if (!__rseq_active)
+ {
+ __rseq_abi.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED;
+ return;
+ }
+
if (__rseq_abi.cpu_id != RSEQ_CPU_ID_UNINITIALIZED)
__libc_fatal ("glibc fatal error: "
"rseq already initialized for this thread\n");
@@ -64,6 +80,11 @@ rseq_register_current_thread (void)
}
}
#else /* RSEQ_SIG */
+static inline void
+rseq_active_init (void)
+{
+}
+
static inline void
rseq_register_current_thread (void)
{
diff --git a/sysdeps/unix/sysv/linux/rseq-sym.c b/sysdeps/unix/sysv/linux/rseq-sym.c
index 090093408f1a4b3f..78d3a9dd8355436b 100644
--- a/sysdeps/unix/sysv/linux/rseq-sym.c
+++ b/sysdeps/unix/sysv/linux/rseq-sym.c
@@ -19,8 +19,11 @@
#include <stdint.h>
#include <kernel-features.h>
#include <sys/rseq.h>
+#include <rseq-internal.h>
__thread struct rseq __rseq_abi =
{
.cpu_id = RSEQ_CPU_ID_UNINITIALIZED,
};
+
+_Bool __rseq_active __attribute__ ((nocommon));
diff --git a/sysdeps/unix/sysv/linux/tst-rseq-nptl.c b/sysdeps/unix/sysv/linux/tst-rseq-nptl.c
index 5e788dcfa9eef8ef..ed846e9f5d5a5f4e 100644
--- a/sysdeps/unix/sysv/linux/tst-rseq-nptl.c
+++ b/sysdeps/unix/sysv/linux/tst-rseq-nptl.c
@@ -250,6 +250,10 @@ do_rseq_test (void)
static int
do_test (void)
{
+ extern _Bool __rseq_active;
+ if (!__rseq_active)
+ FAIL_UNSUPPORTED ("/etc/glibc.rseq.enabled missing, test disabled");
+
return do_rseq_test ();
}
diff --git a/sysdeps/unix/sysv/linux/tst-rseq.c b/sysdeps/unix/sysv/linux/tst-rseq.c
index aa902fb26a64f917..60eaab4bc13d1275 100644
--- a/sysdeps/unix/sysv/linux/tst-rseq.c
+++ b/sysdeps/unix/sysv/linux/tst-rseq.c
@@ -57,6 +57,10 @@ do_rseq_test (void)
static int
do_test (void)
{
+ extern _Bool __rseq_active;
+ if (!__rseq_active)
+ FAIL_UNSUPPORTED ("/etc/glibc.rseq.enabled missing, test disabled");
+
do_rseq_test ();
return 0;
}

6
glibc.spec
View File

@ -96,7 +96,7 @@
Summary: The GNU libc libraries
Name: glibc
Version: %{glibcversion}
Release: 18%{?dist}
Release: 19%{?dist}
# In general, GPLv2+ is used by programs, LGPLv2+ is used for
# libraries.
@ -167,6 +167,7 @@ Patch17: glibc-cs-path.patch
Patch18: glibc-c-utf8-locale.patch
Patch23: glibc-python3.patch
Patch29: glibc-fedora-nsswitch.patch
Patch30: glibc-rseq-disable.patch
##############################################################################
# Continued list of core "glibc" package information:
@ -2017,6 +2018,9 @@ fi
%files -f compat-libpthread-nonshared.filelist -n compat-libpthread-nonshared
%changelog
* Fri Jul 10 2020 Florian Weimer <fweimer@redhat.com> - 2.31.9000-19
- Disable rseq registration by default to help Firefox (#1855729)
* Thu Jul 09 2020 Florian Weimer <fweimer@redhat.com> - 2.31.9000-18
- Auto-sync with upstream branch master,
commit ffb17e7ba3a5ba9632cee97330b325072fbe41dd: