4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski <luto@xxxxxxxxxx> commit d744dcad39094c9187075e274d1cdef79c57c8b5 upstream. Much of the test design could apply to set_thread_area() (i.e. GDT), not just modify_ldt(). Add set_thread_area() to the install_valid_mode() helper. Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Borislav Petkov <bpetkov@xxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/02c23f8fba5547007f741dc24c3926e5284ede02.1509794321.git.luto@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/x86/ldt_gdt.c | 53 +++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 16 deletions(-) --- a/tools/testing/selftests/x86/ldt_gdt.c +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -137,30 +137,51 @@ static void check_valid_segment(uint16_t } } -static bool install_valid_mode(const struct user_desc *desc, uint32_t ar, - bool oldmode) +static bool install_valid_mode(const struct user_desc *d, uint32_t ar, + bool oldmode, bool ldt) { - int ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11, - desc, sizeof(*desc)); - if (ret < -1) - errno = -ret; + struct user_desc desc = *d; + int ret; + + if (!ldt) { +#ifndef __i386__ + /* No point testing set_thread_area in a 64-bit build */ + return false; +#endif + if (!gdt_entry_num) + return false; + desc.entry_number = gdt_entry_num; + + ret = syscall(SYS_set_thread_area, &desc); + } else { + ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11, + &desc, sizeof(desc)); + + if (ret < -1) + errno = -ret; + + if (ret != 0 && errno == ENOSYS) { + printf("[OK]\tmodify_ldt returned -ENOSYS\n"); + return false; + } + } + if (ret == 0) { - uint32_t limit = desc->limit; - if (desc->limit_in_pages) + uint32_t limit = desc.limit; + if (desc.limit_in_pages) limit = (limit << 12) + 4095; - check_valid_segment(desc->entry_number, 1, ar, limit, true); + check_valid_segment(desc.entry_number, ldt, ar, limit, true); return true; - } else if (errno == ENOSYS) { - printf("[OK]\tmodify_ldt returned -ENOSYS\n"); - return false; } else { - if (desc->seg_32bit) { - printf("[FAIL]\tUnexpected modify_ldt failure %d\n", + if (desc.seg_32bit) { + printf("[FAIL]\tUnexpected %s failure %d\n", + ldt ? "modify_ldt" : "set_thread_area", errno); nerrs++; return false; } else { - printf("[OK]\tmodify_ldt rejected 16 bit segment\n"); + printf("[OK]\t%s rejected 16 bit segment\n", + ldt ? "modify_ldt" : "set_thread_area"); return false; } } @@ -168,7 +189,7 @@ static bool install_valid_mode(const str static bool install_valid(const struct user_desc *desc, uint32_t ar) { - return install_valid_mode(desc, ar, false); + return install_valid_mode(desc, ar, false, true); } static void install_invalid(const struct user_desc *desc, bool oldmode)