glibc/include/sys/cdefs.h
Frédéric Bérat eea000f6e6 misc/sys/cdefs.h: Create FORTIFY redirects for internal calls
The __REDIRECT* macros are creating aliases which may lead to unwanted
PLT entries when fortification is enabled.
To prevent these entries, the REDIRECT alias should be set to point to the
existing __GI_* aliases.
This is done transparently by creating a __REDIRECT_FORTIFY* version of
these macros, that can be overwritten internally when necessary.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-07-05 16:59:48 +02:00

60 lines
1.8 KiB
C

#ifndef _SYS_CDEFS_H
/* This is outside of _ISOMAC to enforce that _Static_assert always
uses the two-argument form. This can be removed once the minimum
GCC version used to compile glibc is GCC 9.1. */
#ifndef __cplusplus
# define _Static_assert(expr, diagnostic) _Static_assert (expr, diagnostic)
#endif
#include <misc/sys/cdefs.h>
#ifndef _ISOMAC
/* The compiler will optimize based on the knowledge the parameter is
not NULL. This will omit tests. A robust implementation cannot allow
this so when compiling glibc itself we ignore this attribute. */
# undef __nonnull
# define __nonnull(params)
extern void __chk_fail (void) __attribute__ ((__noreturn__));
libc_hidden_proto (__chk_fail)
rtld_hidden_proto (__chk_fail)
/* If we are using redirects internally to support long double,
we need to tweak some macros to ensure the PLT bypass tricks
continue to work in libc. */
#if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1 && IS_IN (libc) && defined SHARED
# undef __LDBL_REDIR_DECL
# define __LDBL_REDIR_DECL(func) \
extern __typeof(func) func __asm (__ASMNAME ("__GI____ieee128_" #func));
# undef libc_hidden_ldbl_proto
# define libc_hidden_ldbl_proto(func, attrs...) \
extern __typeof(func) ___ieee128_ ## func; \
libc_hidden_proto (___ieee128_ ## func, ##attrs);
# undef __LDBL_REDIR2_DECL
# define __LDBL_REDIR2_DECL(func) \
extern __typeof(__ ## func) __ ## func __asm (__ASMNAME ("__GI____ieee128___" #func));
#endif
#if defined SHARED
#if IS_IN (libc) && __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
#undef __REDIRECT_FORTIFY
#define __REDIRECT_FORTIFY(name, proto, alias) \
__REDIRECT(name, proto, __GI_##alias)
#undef __REDIRECT_FORTIFY_NTH
#define __REDIRECT_FORTIFY_NTH(name, proto, alias) \
__REDIRECT_NTH(name, proto, __GI_##alias)
#endif
#endif /* defined SHARED */
#endif /* !defined _ISOMAC */
#endif