Commit 1c275925 authored by Alex Barcelo's avatar Alex Barcelo Committed by Riku Voipio
Browse files

signal: added a wrapper for sigprocmask function 



Create a wrapper for signal mask changes initiated by the guest;
(this includes syscalls and also the sigreturns from signal.c)
this will give us a place to put code which prevents the guest
from changing the handling of signals used by QEMU itself
internally.

The wrapper is called from all the guest-initiated sigprocmask, but
is not called from internal qemu sigprocmask calls.

Signed-off-by: default avatarAlex Barcelo <abarcelo@ac.upc.edu>
[PMM: Added calls to wrapper for sigprocmask uses in signal.c
when setting the signal mask on entry and exit from signal
handlers, since these also are guest-provided signal masks.]
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarRiku Voipio <riku.voipio@linaro.org>
parent 6b1275ff

linux-user/qemu.h

+1 −0
Original line number Diff line number Diff line
@@ -235,6 +235,7 @@ int host_to_target_signal(int sig); 
long do_sigreturn(CPUArchState *env);

long do_rt_sigreturn(CPUArchState *env);

abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp);

int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset);



#ifdef TARGET_I386

/* vm86.c */

linux-user/signal.c

+34 −24
Original line number Diff line number Diff line
@@ -197,6 +197,16 @@ void target_to_host_old_sigset(sigset_t *sigset, 
    target_to_host_sigset(sigset, &d);

}



/* Wrapper for sigprocmask function

 * Emulates a sigprocmask in a safe way for the guest. Note that set and oldset

 * are host signal set, not guest ones. This wraps the sigprocmask host calls

 * that should be protected (calls originated from guest)

 */

int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset)

{

    return sigprocmask(how, set, oldset);

}



/* siginfo conversion */



static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
@@ -1056,7 +1066,7 @@ long do_sigreturn(CPUX86State *env) 
    }



    target_to_host_sigset_internal(&set, &target_set);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    /* restore registers */

    if (restore_sigcontext(env, &frame->sc, &eax))
@@ -1081,7 +1091,7 @@ long do_rt_sigreturn(CPUX86State *env) 
        if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))

                goto badframe;

        target_to_host_sigset(&set, &frame->uc.tuc_sigmask);

        sigprocmask(SIG_SETMASK, &set, NULL);

        do_sigprocmask(SIG_SETMASK, &set, NULL);



	if (restore_sigcontext(env, &frame->uc.tuc_mcontext, &eax))

		goto badframe;
@@ -1220,7 +1230,7 @@ static int target_restore_sigframe(CPUARMState *env, 
    uint64_t pstate;



    target_to_host_sigset(&set, &sf->uc.tuc_sigmask);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    for (i = 0; i < 31; i++) {

        __get_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
@@ -1861,7 +1871,7 @@ static long do_sigreturn_v1(CPUARMState *env) 
        }



        target_to_host_sigset_internal(&host_set, &set);

        sigprocmask(SIG_SETMASK, &host_set, NULL);

        do_sigprocmask(SIG_SETMASK, &host_set, NULL);



	if (restore_sigcontext(env, &frame->sc))

		goto badframe;
@@ -1942,7 +1952,7 @@ static int do_sigframe_return_v2(CPUARMState *env, target_ulong frame_addr, 
    abi_ulong *regspace;



    target_to_host_sigset(&host_set, &uc->tuc_sigmask);

    sigprocmask(SIG_SETMASK, &host_set, NULL);

    do_sigprocmask(SIG_SETMASK, &host_set, NULL);



    if (restore_sigcontext(env, &uc->tuc_mcontext))

        return 1;
@@ -2033,7 +2043,7 @@ static long do_rt_sigreturn_v1(CPUARMState *env) 
                goto badframe;



        target_to_host_sigset(&host_set, &frame->uc.tuc_sigmask);

        sigprocmask(SIG_SETMASK, &host_set, NULL);

        do_sigprocmask(SIG_SETMASK, &host_set, NULL);



	if (restore_sigcontext(env, &frame->uc.tuc_mcontext))

		goto badframe;
@@ -2444,7 +2454,7 @@ long do_sigreturn(CPUSPARCState *env) 
        }



        target_to_host_sigset_internal(&host_set, &set);

        sigprocmask(SIG_SETMASK, &host_set, NULL);

        do_sigprocmask(SIG_SETMASK, &host_set, NULL);



        if (err)

                goto segv_and_exit;
@@ -2567,7 +2577,7 @@ void sparc64_set_context(CPUSPARCState *env) 
                goto do_sigsegv;

        }

        target_to_host_sigset_internal(&set, &target_set);

        sigprocmask(SIG_SETMASK, &set, NULL);

        do_sigprocmask(SIG_SETMASK, &set, NULL);

    }

    env->pc = pc;

    env->npc = npc;
@@ -2656,7 +2666,7 @@ void sparc64_get_context(CPUSPARCState *env) 


    err = 0;



    sigprocmask(0, NULL, &set);

    do_sigprocmask(0, NULL, &set);

    host_to_target_sigset_internal(&target_set, &set);

    if (TARGET_NSIG_WORDS == 1) {

        err |= __put_user(target_set.sig[0],
@@ -2991,7 +3001,7 @@ long do_sigreturn(CPUMIPSState *regs) 
    }



    target_to_host_sigset_internal(&blocked, &target_set);

    sigprocmask(SIG_SETMASK, &blocked, NULL);

    do_sigprocmask(SIG_SETMASK, &blocked, NULL);



    if (restore_sigcontext(regs, &frame->sf_sc))

   	goto badframe;
@@ -3095,7 +3105,7 @@ long do_rt_sigreturn(CPUMIPSState *env) 
   	goto badframe;



    target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask);

    sigprocmask(SIG_SETMASK, &blocked, NULL);

    do_sigprocmask(SIG_SETMASK, &blocked, NULL);



    if (restore_sigcontext(env, &frame->rs_uc.tuc_mcontext))

        goto badframe;
@@ -3385,7 +3395,7 @@ long do_sigreturn(CPUSH4State *regs) 
        goto badframe;



    target_to_host_sigset_internal(&blocked, &target_set);

    sigprocmask(SIG_SETMASK, &blocked, NULL);

    do_sigprocmask(SIG_SETMASK, &blocked, NULL);



    if (restore_sigcontext(regs, &frame->sc, &r0))

        goto badframe;
@@ -3414,7 +3424,7 @@ long do_rt_sigreturn(CPUSH4State *regs) 
   	goto badframe;



    target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);

    sigprocmask(SIG_SETMASK, &blocked, NULL);

    do_sigprocmask(SIG_SETMASK, &blocked, NULL);



    if (restore_sigcontext(regs, &frame->uc.tuc_mcontext, &r0))

        goto badframe;
@@ -3644,7 +3654,7 @@ long do_sigreturn(CPUMBState *env) 
            goto badframe;

    }

    target_to_host_sigset_internal(&set, &target_set);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    restore_sigcontext(&frame->uc.tuc_mcontext, env);

    /* We got here through a sigreturn syscall, our path back is via an
@@ -3819,7 +3829,7 @@ long do_sigreturn(CPUCRISState *env) 
			goto badframe;

	}

	target_to_host_sigset_internal(&set, &target_set);

	sigprocmask(SIG_SETMASK, &set, NULL);

        do_sigprocmask(SIG_SETMASK, &set, NULL);



	restore_sigcontext(&frame->sc, env);

	unlock_user_struct(frame, frame_addr, 0);
@@ -4350,7 +4360,7 @@ long do_sigreturn(CPUS390XState *env) 
    }



    target_to_host_sigset_internal(&set, &target_set);

    sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */

    do_sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */



    if (restore_sigregs(env, &frame->sregs)) {

        goto badframe;
@@ -4378,7 +4388,7 @@ long do_rt_sigreturn(CPUS390XState *env) 
    }

    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);



    sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */

    do_sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */



    if (restore_sigregs(env, &frame->uc.tuc_mcontext)) {

        goto badframe;
@@ -4906,7 +4916,7 @@ long do_sigreturn(CPUPPCState *env) 
       goto sigsegv;

#endif

    target_to_host_sigset_internal(&blocked, &set);

    sigprocmask(SIG_SETMASK, &blocked, NULL);

    do_sigprocmask(SIG_SETMASK, &blocked, NULL);



    if (__get_user(sr_addr, &sc->regs))

        goto sigsegv;
@@ -4950,7 +4960,7 @@ static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig) 
        return 1;



    target_to_host_sigset_internal(&blocked, &set);

    sigprocmask(SIG_SETMASK, &blocked, NULL);

    do_sigprocmask(SIG_SETMASK, &blocked, NULL);

    if (restore_user_regs(env, mcp, sig))

        goto sigsegv;
@@ -5324,7 +5334,7 @@ long do_sigreturn(CPUM68KState *env) 
    }



    target_to_host_sigset_internal(&set, &target_set);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    /* restore registers */
@@ -5352,7 +5362,7 @@ long do_rt_sigreturn(CPUM68KState *env) 
        goto badframe;



    target_to_host_sigset_internal(&set, &target_set);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    /* restore registers */
@@ -5599,7 +5609,7 @@ long do_sigreturn(CPUAlphaState *env) 
    }



    target_to_host_sigset_internal(&set, &target_set);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    if (restore_sigcontext(env, sc)) {

        goto badframe;
@@ -5622,7 +5632,7 @@ long do_rt_sigreturn(CPUAlphaState *env) 
        goto badframe;

    }

    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);

    sigprocmask(SIG_SETMASK, &set, NULL);

    do_sigprocmask(SIG_SETMASK, &set, NULL);



    if (restore_sigcontext(env, &frame->uc.tuc_mcontext)) {

        goto badframe;
@@ -5739,7 +5749,7 @@ void process_pending_signals(CPUArchState *cpu_env) 
            sigaddset(&set, target_to_host_signal(sig));



        /* block signals in the handler using Linux */

        sigprocmask(SIG_BLOCK, &set, &old_set);

        do_sigprocmask(SIG_BLOCK, &set, &old_set);

        /* save the previous blocked signal state to restore it at the

           end of the signal execution (see do_sigreturn) */

        host_to_target_sigset_internal(&target_old_set, &old_set);

linux-user/syscall.c

+7 −7
Original line number Diff line number Diff line
@@ -6029,7 +6029,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
        {

            sigset_t cur_set;

            abi_ulong target_set;

            sigprocmask(0, NULL, &cur_set);

            do_sigprocmask(0, NULL, &cur_set);

            host_to_target_old_sigset(&target_set, &cur_set);

            ret = target_set;

        }
@@ -6040,10 +6040,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
        {

            sigset_t set, oset, cur_set;

            abi_ulong target_set = arg1;

            sigprocmask(0, NULL, &cur_set);

            do_sigprocmask(0, NULL, &cur_set);

            target_to_host_old_sigset(&set, &target_set);

            sigorset(&set, &set, &cur_set);

            sigprocmask(SIG_SETMASK, &set, &oset);

            do_sigprocmask(SIG_SETMASK, &set, &oset);

            host_to_target_old_sigset(&target_set, &oset);

            ret = target_set;

        }
@@ -6074,7 +6074,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
            mask = arg2;

            target_to_host_old_sigset(&set, &mask);



            ret = get_errno(sigprocmask(how, &set, &oldset));

            ret = get_errno(do_sigprocmask(how, &set, &oldset));

            if (!is_error(ret)) {

                host_to_target_old_sigset(&mask, &oldset);

                ret = mask;
@@ -6108,7 +6108,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
                how = 0;

                set_ptr = NULL;

            }

            ret = get_errno(sigprocmask(how, set_ptr, &oldset));

            ret = get_errno(do_sigprocmask(how, set_ptr, &oldset));

            if (!is_error(ret) && arg3) {

                if (!(p = lock_user(VERIFY_WRITE, arg3, sizeof(target_sigset_t), 0)))

                    goto efault;
@@ -6148,7 +6148,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
                how = 0;

                set_ptr = NULL;

            }

            ret = get_errno(sigprocmask(how, set_ptr, &oldset));

            ret = get_errno(do_sigprocmask(how, set_ptr, &oldset));

            if (!is_error(ret) && arg3) {

                if (!(p = lock_user(VERIFY_WRITE, arg3, sizeof(target_sigset_t), 0)))

                    goto efault;
@@ -8161,7 +8161,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
            }

            mask = arg2;

            target_to_host_old_sigset(&set, &mask);

            sigprocmask(how, &set, &oldset);

            do_sigprocmask(how, &set, &oldset);

            host_to_target_old_sigset(&mask, &oldset);

            ret = mask;

        }