[glibc/maskray/relr] timex: Use 64-bit fields on 32-bit TIMESIZE=64 systems (BZ #28469)

[glibc/maskray/relr] timex: Use 64-bit fields on 32-bit TIMESIZE=64 systems (BZ #28469)

[Fangrui Song]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=1d550265a75b412cea4889a50b101395f6a8e025

commit 1d550265a75b412cea4889a50b101395f6a8e025
Author: Stafford Horne <shorne@gmail.com>
Date:   Fri Oct 15 06:17:41 2021 +0900

    timex: Use 64-bit fields on 32-bit TIMESIZE=64 systems (BZ #28469)
    
    This was found when testing the OpenRISC port I am working on.  These
    two tests fail with SIGSEGV:
    
      FAIL: misc/tst-ntp_gettime
      FAIL: misc/tst-ntp_gettimex
    
    This was found to be due to the kernel overwriting the stack space
    allocated by the timex structure.  The reason for the overwrite being
    that the kernel timex has 64-bit fields and user space code only
    allocates enough stack space for timex with 32-bit fields.
    
    On 32-bit systems with TIMESIZE=64 __USE_TIME_BITS64 is not defined.
    This causes the timex structure to use 32-bit fields with type
    __syscall_slong_t.
    
    This patch adjusts the ifdef condition to allow 32-bit systems with
    TIMESIZE=64 to use the 64-bit long long timex definition.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 sysdeps/unix/sysv/linux/bits/timex.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sysdeps/unix/sysv/linux/bits/timex.h b/sysdeps/unix/sysv/linux/bits/timex.h
index ee37694e8f..4a5db6deca 100644
--- a/sysdeps/unix/sysv/linux/bits/timex.h
+++ b/sysdeps/unix/sysv/linux/bits/timex.h
@@ -25,7 +25,7 @@
 
 struct timex
 {
-# ifdef __USE_TIME_BITS64
+# if defined __USE_TIME_BITS64 || (__TIMESIZE == 64 && __WORDSIZE == 32)
   unsigned int modes;          /* mode selector */
   int :32;                     /* pad */
   long long offset;            /* time offset (usec) */