diff options
Diffstat (limited to 'arch/x86/kernel/umip.c')
| -rw-r--r-- | arch/x86/kernel/umip.c | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index d80b816228ea..6ba82be68cff 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -11,6 +11,10 @@ #include <asm/traps.h> #include <asm/insn.h> #include <asm/insn-eval.h> +#include <linux/ratelimit.h> + +#undef pr_fmt +#define pr_fmt(fmt) "umip: " fmt /** DOC: Emulation for User-Mode Instruction Prevention (UMIP) * @@ -196,6 +200,41 @@ static int emulate_umip_insn(struct insn *insn, int umip_inst, } /** + * force_sig_info_umip_fault() - Force a SIGSEGV with SEGV_MAPERR + * @addr: Address that caused the signal + * @regs: Register set containing the instruction pointer + * + * Force a SIGSEGV signal with SEGV_MAPERR as the error code. This function is + * intended to be used to provide a segmentation fault when the result of the + * UMIP emulation could not be copied to the user space memory. + * + * Returns: none + */ +static void force_sig_info_umip_fault(void __user *addr, struct pt_regs *regs) +{ + siginfo_t info; + struct task_struct *tsk = current; + + tsk->thread.cr2 = (unsigned long)addr; + tsk->thread.error_code = X86_PF_USER | X86_PF_WRITE; + tsk->thread.trap_nr = X86_TRAP_PF; + + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_code = SEGV_MAPERR; + info.si_addr = addr; + force_sig_info(SIGSEGV, &info, tsk); + + if (!(show_unhandled_signals && unhandled_signal(tsk, SIGSEGV))) + return; + + pr_err_ratelimited("%s[%d] umip emulation segfault ip:%lx sp:%lx error:%x in %lx\n", + tsk->comm, task_pid_nr(tsk), regs->ip, + regs->sp, X86_PF_USER | X86_PF_WRITE, + regs->ip); +} + +/** * fixup_umip_exception() - Fixup a general protection fault caused by UMIP * @regs: Registers as saved when entering the #GP handler * @@ -311,8 +350,14 @@ bool fixup_umip_exception(struct pt_regs *regs) return false; nr_copied = copy_to_user(uaddr, dummy_data, dummy_data_size); - if (nr_copied > 0) - return false; + if (nr_copied > 0) { + /* + * If copy fails, send a signal and tell caller that + * fault was fixed up. + */ + force_sig_info_umip_fault(uaddr, regs); + return true; + } } /* increase IP to let the program keep going */ |