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[SIGNAL] Refined handling of invalid sigsetsize in syscall_rt_sigaction #4335

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Merged
ptitSeb merged 2 commits into from
Sep 1, 2026
+7 −11
Merged

[SIGNAL] Refined handling of invalid sigsetsize in syscall_rt_sigaction #4335

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01c0d7f
[SIGNAL] Refined handling of invalid sigsetsize in syscall_rt_sigaction
ksco Sep 1, 2026
c1e38ba
Fixed review
ksco Sep 1, 2026
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18 changes: 7 additions & 11 deletions src/libtools/signals.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1533,27 +1533,23 @@ __attribute__((alias("my_sigaction")));
int EXPORT my_syscall_rt_sigaction(x64emu_t* emu, int signum, const x64_sigaction_restorer_t *act, x64_sigaction_restorer_t *oldact, int sigsetsize)
{
printf_log(LOG_DEBUG, "Syscall/Sigaction(signum=%d, act=%p, old=%p, size=%d)\n", signum, act, oldact, sigsetsize);
if(signum<0 || signum>MAX_SIGNAL) {
if (signum < 0 || signum > MAX_SIGNAL || sigsetsize != 8 /* sizeof(sigset_t) */) {
errno = EINVAL;
return -1;
}

if(signum==X64_SIGSEGV && emu->context->no_sigsegv)
return 0;
size_t emulated_sigsetsize = sigsetsize > 0 ? (size_t)sigsetsize : 0;
if (emulated_sigsetsize > sizeof(sigset_t))
emulated_sigsetsize = sizeof(sigset_t);
// TODO, how to handle sigsetsize>4?!
if(signum==32 || signum==33) {
// cannot use libc sigaction, need to use syscall!
struct kernel_sigaction newact = {0};
struct kernel_sigaction old = {0};
size_t kernel_sigsetsize = emulated_sigsetsize > 16 ? 16 : emulated_sigsetsize;
size_t kernel_sigsetsize = sigsetsize > 16 ? 16 : sigsetsize;
if(act) {
printf_log(LOG_DEBUG, " New (kernel) action flags=0x%x mask=0x%lx\n", act->sa_flags, *(uint64_t*)&act->sa_mask);
my_context->sigflags[signum] = act->sa_flags;
memset(&my_context->sigmask[signum], 0, sizeof(sigset_t));
memcpy(&my_context->sigmask[signum], &act->sa_mask, emulated_sigsetsize);
memcpy(&my_context->sigmask[signum], &act->sa_mask, sigsetsize);
memcpy(&newact.sa_mask, &act->sa_mask, kernel_sigsetsize);
newact.sa_flags = act->sa_flags&~0x04000000; // No sa_restorer...
if(act->sa_flags&0x04) {
Expand Down Expand Up @@ -1595,13 +1591,13 @@ int EXPORT my_syscall_rt_sigaction(x64emu_t* emu, int signum, const x64_sigactio
int box64_signal = is_box64_signal(signum);
uintptr_t old_handler = my_context->signals[signum];
if (oldact && box64_signal)
fill_emulated_sigaction_restorer(oldact, signum, old_handler, emulated_sigsetsize);
fill_emulated_sigaction_restorer(oldact, signum, old_handler, sigsetsize);
if(act) {
printf_log(LOG_DEBUG, " New action for signal #%d flags=0x%x mask=0x%lx\n", signum, act->sa_flags, *(uint64_t*)&act->sa_mask);
my_context->sigflags[signum] = act->sa_flags;
memset(&my_context->sigmask[signum], 0, sizeof(sigset_t));
memcpy(&my_context->sigmask[signum], &act->sa_mask, emulated_sigsetsize);
memcpy(&newact.sa_mask, &act->sa_mask, emulated_sigsetsize);
memcpy(&my_context->sigmask[signum], &act->sa_mask, sigsetsize);
memcpy(&newact.sa_mask, &act->sa_mask, sigsetsize);
newact.sa_flags = act->sa_flags&~0x04000000; // No sa_restorer...
if (act->sa_flags & 0x04) {
my_context->signals[signum] = (uintptr_t)act->_u._sa_sigaction;
Expand Down Expand Up @@ -1631,7 +1627,7 @@ int EXPORT my_syscall_rt_sigaction(x64emu_t* emu, int signum, const x64_sigactio
ret = sigaction(signal_from_x64(signum), act?&newact:NULL, oldact?&old:NULL);
if (oldact && ret == 0 && !box64_signal) {
oldact->sa_flags = old.sa_flags;
memcpy(&oldact->sa_mask, &old.sa_mask, emulated_sigsetsize > 8 ? 8 : emulated_sigsetsize);
memcpy(&oldact->sa_mask, &old.sa_mask, sigsetsize > 8 ? 8 : sigsetsize);
if(old.sa_flags & 0x04)
oldact->_u._sa_sigaction = old.sa_sigaction; //TODO should wrap...
else
Expand Down
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