The implementation is mostly from NetBSD, except for switching fgets to
pure inline, and the addition of fgets_unlocked, fread, and fread_unlocked
for parity with glibc. The following functions are also guarded in glibc:
asprintf, dprintf, fprintf, printf, vasprintf, vdprintf, vfprintf, vprintf.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
The implementation is from NetBSD, with the addition of mempcpy (a GNU
extension) for parity with glibc and libssp.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
The Object Size Checking (-D_FORTIFY_SOURCE=*) functionality provides
wrappers around functions suspectible to buffer overflows. While
independent from Stack Smashing Protection (-fstack-protector*), they
are often used and implemented together.
While GCC also provides an implementation in libssp, it is completely
broken (CVE-2016-4973, RHBZ#1324759) and seemingly unfixable, as there
is no reliable way for a preprocessor macro to trigger a link flag.
Therefore, adding this here is necessary to make it work.
Note that this does require building gcc with --disable-libssp and
gcc_cv_libc_provides_ssp=yes.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
Compiling with any of the -fstack-protector* flags requires the
__stack_chk_guard data import (which needs to be initialized) and the
__stack_chk_fail{,_local} functions. While GCC's own libssp can provide
these, it is better that we provide these ourselves. The implementation
is custom due to being OS-specific.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
Yaakov Selkowitz