mirror of git://sourceware.org/git/glibc.git
541641a3de
Previously, CET was enabled by kernel before passing control to user space and the startup code must disable CET if applications or shared libraries aren't CET enabled. Since the current kernel only supports shadow stack and won't enable shadow stack before passing control to user space, we need to enable shadow stack during startup if the application and all shared library are shadow stack enabled. There is no need to disable shadow stack at startup. Shadow stack can only be enabled in a function which will never return. Otherwise, shadow stack will underflow at the function return. 1. GL(dl_x86_feature_1) is set to the CET features which are supported by the processor and are not disabled by the tunable. Only non-zero features in GL(dl_x86_feature_1) should be enabled. After enabling shadow stack with ARCH_SHSTK_ENABLE, ARCH_SHSTK_STATUS is used to check if shadow stack is really enabled. 2. Use ARCH_SHSTK_ENABLE in RTLD_START in dynamic executable. It is safe since RTLD_START never returns. 3. Call arch_prctl (ARCH_SHSTK_ENABLE) from ARCH_SETUP_TLS in static executable. Since the start function using ARCH_SETUP_TLS never returns, it is safe to enable shadow stack in ARCH_SETUP_TLS. |
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| .. | ||
| bits | ||
| include | ||
| sys | ||
| Implies | ||
| Makefile | ||
| arch-pkey.h | ||
| dl-cet.h | ||
| dl-hwcap2.h | ||
| dl-minsigstacksize.h | ||
| dl-sysdep.c | ||
| elf-read-prop.h | ||
| elision-conf.c | ||
| elision-conf.h | ||
| elision-lock.c | ||
| elision-timed.c | ||
| elision-trylock.c | ||
| elision-unlock.c | ||
| gettimeofday.c | ||
| hle.h | ||
| jmp_buf-ssp.sym | ||
| longjmp.c | ||
| pkey_get.c | ||
| pkey_set.c | ||
| setjmpP.h | ||
| sysconf.c | ||
| time.c | ||
| tst-cet-property-1.c | ||
| tst-cet-property-2.c | ||
| tst-cet-property-dep-2.S | ||
| tst-cet-setcontext-1.c | ||
| tst-cet-vfork-1.c | ||
| tst-saved_mask-1.c | ||
| xstatver.h | ||