Commit-ID: 76dee4a72849561f6ffacc357cfd0aa33336081a Gitweb: https://git.kernel.org/tip/76dee4a72849561f6ffacc357cfd0aa33336081a Author: Jann Horn <ja...@google.com> AuthorDate: Tue, 28 Aug 2018 22:14:16 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Mon, 3 Sep 2018 15:12:08 +0200
x86/kprobes: Inline kprobe_exceptions_notify() into do_general_protection() The opaque plumbing of #GP from do_general_protection() through notify_die() into kprobe_exceptions_notify() makes it hard to understand what's going on. Suggested-by: Andy Lutomirski <l...@kernel.org> Signed-off-by: Jann Horn <ja...@google.com> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Tested-by: Kees Cook <keesc...@chromium.org> Acked-by: Masami Hiramatsu <mhira...@kernel.org> Cc: kernel-harden...@lists.openwall.com Cc: dvyu...@google.com Cc: "Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com> Cc: "David S. Miller" <da...@davemloft.net> Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: linux-fsde...@vger.kernel.org Cc: Borislav Petkov <b...@alien8.de> Link: https://lkml.kernel.org/r/20180828201421.157735-3-ja...@google.com --- arch/x86/kernel/kprobes/core.c | 31 +------------------------------ arch/x86/kernel/traps.c | 10 ++++++++++ 2 files changed, 11 insertions(+), 30 deletions(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index b0d1e81c96bb..467ac22691b0 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -1028,42 +1028,13 @@ int kprobe_fault_handler(struct pt_regs *regs, int trapnr) if (fixup_exception(regs, trapnr)) return 1; - /* - * fixup routine could not handle it, - * Let do_page_fault() fix it. - */ + /* fixup routine could not handle it. */ } return 0; } NOKPROBE_SYMBOL(kprobe_fault_handler); -/* - * Wrapper routine for handling exceptions. - */ -int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, - void *data) -{ - struct die_args *args = data; - int ret = NOTIFY_DONE; - - if (args->regs && user_mode(args->regs)) - return ret; - - if (val == DIE_GPF) { - /* - * To be potentially processing a kprobe fault and to - * trust the result from kprobe_running(), we have - * be non-preemptible. - */ - if (!preemptible() && kprobe_running() && - kprobe_fault_handler(args->regs, args->trapnr)) - ret = NOTIFY_STOP; - } - return ret; -} -NOKPROBE_SYMBOL(kprobe_exceptions_notify); - bool arch_within_kprobe_blacklist(unsigned long addr) { bool is_in_entry_trampoline_section = false; diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index e6db475164ed..bf9ab1aaa175 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -556,6 +556,16 @@ do_general_protection(struct pt_regs *regs, long error_code) tsk->thread.error_code = error_code; tsk->thread.trap_nr = X86_TRAP_GP; + + /* + * To be potentially processing a kprobe fault and to + * trust the result from kprobe_running(), we have to + * be non-preemptible. + */ + if (!preemptible() && kprobe_running() && + kprobe_fault_handler(regs, X86_TRAP_GP)) + return; + if (notify_die(DIE_GPF, "general protection fault", regs, error_code, X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP) die("general protection fault", regs, error_code);
