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signal: added a wrapper for sigprocmask function

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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: Alex 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: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
This commit is contained in:
Alex Barcelo 2014-03-14 14:36:55 +00:00 committed by Riku Voipio
parent 6b1275ff15
commit 1c275925bf
3 changed files with 42 additions and 31 deletions
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1
linux-user/qemu.h
View File

@ -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 */

58
linux-user/signal.c
View File

@ -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);

14
linux-user/syscall.c
View File

@ -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;
}