diff options
| author | Florian Weimer <fweimer@redhat.com> | 2022-10-18 17:00:07 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2022-10-18 17:03:55 +0200 |
| commit | 88f4b6929c26f9240a4b0b7dcc62922f02544a09 (patch) | |
| tree | 72acb4a359d3ec56729a910386bd1a002bd69e3c /sysdeps/generic | |
| parent | 246f37d6b1c4c6c0a6365df8783e62e3adf208e8 (diff) | |
| download | glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar.gz glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.tar.bz2 glibc-88f4b6929c26f9240a4b0b7dcc62922f02544a09.zip | |
Introduce <pointer_guard.h>, extracted from <sysdep.h>
This allows us to define a generic no-op version of PTR_MANGLE and
PTR_DEMANGLE. In the future, we can use PTR_MANGLE and PTR_DEMANGLE
unconditionally in C sources, avoiding an unintended loss of hardening
due to missing include files or unlucky header inclusion ordering.
In i386 and x86_64, we can avoid a <tls.h> dependency in the C
code by using the computed constant from <tcb-offsets.h>. <sysdep.h>
no longer includes these definitions, so there is no cyclic dependency
anymore when computing the <tcb-offsets.h> constants.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/generic')
| -rw-r--r-- | sysdeps/generic/pointer_guard.h | 29 | ||||
| -rw-r--r-- | sysdeps/generic/unwind-link.h | 2 |
2 files changed, 30 insertions, 1 deletions
diff --git a/sysdeps/generic/pointer_guard.h b/sysdeps/generic/pointer_guard.h new file mode 100644 index 0000000000..58a624e1d5 --- /dev/null +++ b/sysdeps/generic/pointer_guard.h @@ -0,0 +1,29 @@ +/* Pointer obfuscation implenentation. Generic (no-op) version. + Copyright (C) 2022 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 + <https://www.gnu.org/licenses/>. */ + +#ifndef POINTER_GUARD_H +#define POINTER_GUARD_H + +/* Assembler code depends on PTR_MANGLE not being defined for + optimization purposes. */ +#ifndef __ASSEMBLER__ +# define PTR_MANGLE(x) (void) (x) +# define PTR_DEMANGLE(x) (void) (x) +#endif + +#endif /* POINTER_GUARD_H */ diff --git a/sysdeps/generic/unwind-link.h b/sysdeps/generic/unwind-link.h index 93ee80f3f8..a2076a23bf 100644 --- a/sysdeps/generic/unwind-link.h +++ b/sysdeps/generic/unwind-link.h @@ -31,7 +31,7 @@ unwind_arch_adjustment (void *prev, void *addr) #endif #ifdef SHARED -# include <sysdep.h> +# include <pointer_guard.h> # include <unwind-resume.h> # if UNWIND_LINK_FRAME_STATE_FOR |