commit 6a04404521ac4119ae36827eeb288ea84eee7cf6 Author: Florian Weimer Date: Sat Feb 17 09:17:04 2024 +0100 Linux: Switch back to assembly syscall wrapper for prctl (bug 29770) Commit ff026950e280bc3e9487b41b460fb31bc5b57721 ("Add a C wrapper for prctl [BZ #25896]") replaced the assembler wrapper with a C function. However, on powerpc64le-linux-gnu, the C variadic function implementation requires extra work in the caller to set up the parameter save area. Calling a function that needs a parameter save area without one (because the prototype used indicates the function is not variadic) corrupts the caller's stack. The Linux manual pages project documents prctl as a non-variadic function. This has resulted in various projects over the years using non-variadic prototypes, including the sanitizer libraries in LLVm and GCC (GCC PR 113728). This commit switches back to the assembler implementation on most targets and only keeps the C implementation for x86-64 x32. Also add the __prctl_time64 alias from commit b39ffab860cd743a82c91946619f1b8158b0b65e ("Linux: Add time64 alias for prctl") to sysdeps/unix/sysv/linux/syscalls.list; it was not yet present in commit ff026950e280bc3e9487b41b460fb31bc5b57721. This restores the old ABI on powerpc64le-linux-gnu, thus fixing bug 29770. Reviewed-By: Simon Chopin Resolved conflicts: sysdeps/unix/sysv/linux/syscalls.list sysdeps/unix/sysv/linux/x86_64/x32/prctl.c diff -Nrup a/sysdeps/unix/sysv/linux/prctl.c b/sysdeps/unix/sysv/linux/prctl.c --- a/sysdeps/unix/sysv/linux/prctl.c 2021-08-01 21:33:43.000000000 -0400 +++ b/sysdeps/unix/sysv/linux/prctl.c 1969-12-31 19:00:00.000000000 -0500 @@ -1,45 +0,0 @@ -/* prctl - Linux specific syscall. - Copyright (C) 2020-2021 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - 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 - . */ - -#include -#include -#include - -/* Unconditionally read all potential arguments. This may pass - garbage values to the kernel, but avoids the need for teaching - glibc the argument counts of individual options (including ones - that are added to the kernel in the future). */ - -int -__prctl (int option, ...) -{ - va_list arg; - va_start (arg, option); - unsigned long int arg2 = va_arg (arg, unsigned long int); - unsigned long int arg3 = va_arg (arg, unsigned long int); - unsigned long int arg4 = va_arg (arg, unsigned long int); - unsigned long int arg5 = va_arg (arg, unsigned long int); - va_end (arg); - return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5); -} - -libc_hidden_def (__prctl) -weak_alias (__prctl, prctl) -#if __TIMESIZE != 64 -weak_alias (__prctl, __prctl_time64) -#endif diff -Nrup a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list --- a/sysdeps/unix/sysv/linux/syscalls.list 2021-08-01 21:33:43.000000000 -0400 +++ b/sysdeps/unix/sysv/linux/syscalls.list 2024-02-27 14:33:01.594782897 -0500 @@ -41,6 +41,7 @@ munlockall - munlockall i: munlockall nfsservctl EXTRA nfsservctl i:ipp __compat_nfsservctl nfsservctl@GLIBC_2.0:GLIBC_2.28 pipe - pipe i:f __pipe pipe pipe2 - pipe2 i:fi __pipe2 pipe2 +prctl EXTRA prctl i:iiiii __prctl prctl __prctl_time64 pivot_root EXTRA pivot_root i:ss pivot_root query_module EXTRA query_module i:sipip __compat_query_module query_module@GLIBC_2.0:GLIBC_2.23 quotactl EXTRA quotactl i:isip quotactl diff -Nrup a/sysdeps/unix/sysv/linux/x86_64/x32/prctl.c b/sysdeps/unix/sysv/linux/x86_64/x32/prctl.c --- a/sysdeps/unix/sysv/linux/x86_64/x32/prctl.c 1969-12-31 19:00:00.000000000 -0500 +++ b/sysdeps/unix/sysv/linux/x86_64/x32/prctl.c 2024-02-27 14:35:03.388602623 -0500 @@ -0,0 +1,42 @@ +/* prctl - Linux specific syscall. x86-64 x32 version. + Copyright (C) 2020-2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + . */ + +#include +#include +#include + +/* Unconditionally read all potential arguments. This may pass + garbage values to the kernel, but avoids the need for teaching + glibc the argument counts of individual options (including ones + that are added to the kernel in the future). */ + +int +__prctl (int option, ...) +{ + va_list arg; + va_start (arg, option); + unsigned long int arg2 = va_arg (arg, unsigned long int); + unsigned long int arg3 = va_arg (arg, unsigned long int); + unsigned long int arg4 = va_arg (arg, unsigned long int); + unsigned long int arg5 = va_arg (arg, unsigned long int); + va_end (arg); + return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5); +} + +libc_hidden_def (__prctl) +weak_alias (__prctl, prctl)