Snap for 8522600 from 436980d31c99bdee3c794e26e662e885eba928d6 to tm-release

Change-Id: I35388fa85b1e14024961e02771a7a0ff7eb731e7

libc/SECCOMP_ALLOWLIST_COMMON.TXT

diff --git a/libc/SECCOMP_ALLOWLIST_COMMON.TXT b/libc/SECCOMP_ALLOWLIST_COMMON.TXT
index 6650d7e..c440f9b 100644
--- a/libc/SECCOMP_ALLOWLIST_COMMON.TXT
+++ b/libc/SECCOMP_ALLOWLIST_COMMON.TXT
@@ -74,3 +74,5 @@
 int sched_rr_get_interval_time64(pid_t, timespec64*) lp32
 # Since Linux 5.4, not in glibc. Probed for and conditionally used by ART.
 int userfaultfd(int) all
+# Since Linux 5.9, used by POSIX_SPAWN_CLOEXEC_DEFAULT
+int close_range(unsigned int, unsigned int, int) all

libc/bionic/spawn.cpp

diff --git a/libc/bionic/spawn.cpp b/libc/bionic/spawn.cpp
index 314a056..59f7631 100644
--- a/libc/bionic/spawn.cpp
+++ b/libc/bionic/spawn.cpp
@@ -30,10 +30,12 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <linux/close_range.h>
 #include <signal.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/resource.h>
+#include <sys/syscall.h>
 #include <unistd.h>
 
 #include <android/fdsan.h>
@@ -49,6 +51,9 @@
 
 // mark all open fds except stdin/out/err as close-on-exec
 static int cloexec_except_stdioe() {
+  // requires 5.11+ or ACK 5.10-T kernel, otherwise returns ENOSYS or EINVAL
+  if (!syscall(SYS_close_range, 3, ~0U, CLOSE_RANGE_CLOEXEC)) return 0;
+
   // unfortunately getrlimit can lie:
   // - both soft and hard limits can be lowered to 0, with fds still open, so it can underestimate
   // - in practice it usually is some really large value (like 32K or more)