[PATCH] x86_64: never block forced SIGSEGV
This is the x86_64 version of the signal fix I just posted for i386. This problem was first noticed on PPC and has already been fixed there. But the exact same issue applies to other platforms in the same way. The signal blocking for sa_mask and the handled signal takes place after the handler setup. When the stack is bogus, the handler setup forces a SIGSEGV. But then this will be blocked, and returning to user mode will fault again and iterate. This patch fixes the problem by checking whether signal handler setup failed, and not doing the signal-blocking if so. This copies what was done in the ppc code. I think all architectures' signal handler setup code follows this pattern and needs the change. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
parent
a3a00751ad
commit
0928d6ef7f
|
@ -428,8 +428,8 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
|
||||||
return (void __user *)((rsp - frame_size) & -8UL);
|
return (void __user *)((rsp - frame_size) & -8UL);
|
||||||
}
|
}
|
||||||
|
|
||||||
void ia32_setup_frame(int sig, struct k_sigaction *ka,
|
int ia32_setup_frame(int sig, struct k_sigaction *ka,
|
||||||
compat_sigset_t *set, struct pt_regs * regs)
|
compat_sigset_t *set, struct pt_regs * regs)
|
||||||
{
|
{
|
||||||
struct sigframe __user *frame;
|
struct sigframe __user *frame;
|
||||||
int err = 0;
|
int err = 0;
|
||||||
|
@ -514,14 +514,15 @@ void ia32_setup_frame(int sig, struct k_sigaction *ka,
|
||||||
current->comm, current->pid, frame, regs->rip, frame->pretcode);
|
current->comm, current->pid, frame, regs->rip, frame->pretcode);
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
return;
|
return 1;
|
||||||
|
|
||||||
give_sigsegv:
|
give_sigsegv:
|
||||||
force_sigsegv(sig, current);
|
force_sigsegv(sig, current);
|
||||||
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
void ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
||||||
compat_sigset_t *set, struct pt_regs * regs)
|
compat_sigset_t *set, struct pt_regs * regs)
|
||||||
{
|
{
|
||||||
struct rt_sigframe __user *frame;
|
struct rt_sigframe __user *frame;
|
||||||
int err = 0;
|
int err = 0;
|
||||||
|
@ -613,9 +614,9 @@ void ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
||||||
current->comm, current->pid, frame, regs->rip, frame->pretcode);
|
current->comm, current->pid, frame, regs->rip, frame->pretcode);
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
return;
|
return 1;
|
||||||
|
|
||||||
give_sigsegv:
|
give_sigsegv:
|
||||||
force_sigsegv(sig, current);
|
force_sigsegv(sig, current);
|
||||||
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
|
@ -34,9 +34,9 @@
|
||||||
|
|
||||||
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
|
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
|
||||||
|
|
||||||
void ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
||||||
sigset_t *set, struct pt_regs * regs);
|
sigset_t *set, struct pt_regs * regs);
|
||||||
void ia32_setup_frame(int sig, struct k_sigaction *ka,
|
int ia32_setup_frame(int sig, struct k_sigaction *ka,
|
||||||
sigset_t *set, struct pt_regs * regs);
|
sigset_t *set, struct pt_regs * regs);
|
||||||
|
|
||||||
asmlinkage long
|
asmlinkage long
|
||||||
|
@ -238,7 +238,7 @@ get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
|
||||||
return (void __user *)round_down(rsp - size, 16);
|
return (void __user *)round_down(rsp - size, 16);
|
||||||
}
|
}
|
||||||
|
|
||||||
static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
||||||
sigset_t *set, struct pt_regs * regs)
|
sigset_t *set, struct pt_regs * regs)
|
||||||
{
|
{
|
||||||
struct rt_sigframe __user *frame;
|
struct rt_sigframe __user *frame;
|
||||||
|
@ -327,20 +327,23 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
|
||||||
current->comm, current->pid, frame, regs->rip, frame->pretcode);
|
current->comm, current->pid, frame, regs->rip, frame->pretcode);
|
||||||
#endif
|
#endif
|
||||||
|
|
||||||
return;
|
return 1;
|
||||||
|
|
||||||
give_sigsegv:
|
give_sigsegv:
|
||||||
force_sigsegv(sig, current);
|
force_sigsegv(sig, current);
|
||||||
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* OK, we're invoking a handler
|
* OK, we're invoking a handler
|
||||||
*/
|
*/
|
||||||
|
|
||||||
static void
|
static int
|
||||||
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
|
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
|
||||||
sigset_t *oldset, struct pt_regs *regs)
|
sigset_t *oldset, struct pt_regs *regs)
|
||||||
{
|
{
|
||||||
|
int ret;
|
||||||
|
|
||||||
#ifdef DEBUG_SIG
|
#ifdef DEBUG_SIG
|
||||||
printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n",
|
printk("handle_signal pid:%d sig:%lu rip:%lx rsp:%lx regs=%p\n",
|
||||||
current->pid, sig,
|
current->pid, sig,
|
||||||
|
@ -384,20 +387,22 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
|
||||||
#ifdef CONFIG_IA32_EMULATION
|
#ifdef CONFIG_IA32_EMULATION
|
||||||
if (test_thread_flag(TIF_IA32)) {
|
if (test_thread_flag(TIF_IA32)) {
|
||||||
if (ka->sa.sa_flags & SA_SIGINFO)
|
if (ka->sa.sa_flags & SA_SIGINFO)
|
||||||
ia32_setup_rt_frame(sig, ka, info, oldset, regs);
|
ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
|
||||||
else
|
else
|
||||||
ia32_setup_frame(sig, ka, oldset, regs);
|
ret = ia32_setup_frame(sig, ka, oldset, regs);
|
||||||
} else
|
} else
|
||||||
#endif
|
#endif
|
||||||
setup_rt_frame(sig, ka, info, oldset, regs);
|
ret = setup_rt_frame(sig, ka, info, oldset, regs);
|
||||||
|
|
||||||
if (!(ka->sa.sa_flags & SA_NODEFER)) {
|
if (ret && !(ka->sa.sa_flags & SA_NODEFER)) {
|
||||||
spin_lock_irq(¤t->sighand->siglock);
|
spin_lock_irq(¤t->sighand->siglock);
|
||||||
sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
|
sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask);
|
||||||
sigaddset(¤t->blocked,sig);
|
sigaddset(¤t->blocked,sig);
|
||||||
recalc_sigpending();
|
recalc_sigpending();
|
||||||
spin_unlock_irq(¤t->sighand->siglock);
|
spin_unlock_irq(¤t->sighand->siglock);
|
||||||
}
|
}
|
||||||
|
|
||||||
|
return ret;
|
||||||
}
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
@ -437,8 +442,7 @@ int do_signal(struct pt_regs *regs, sigset_t *oldset)
|
||||||
asm volatile("movq %0,%%db7" : : "r" (current->thread.debugreg7));
|
asm volatile("movq %0,%%db7" : : "r" (current->thread.debugreg7));
|
||||||
|
|
||||||
/* Whee! Actually deliver the signal. */
|
/* Whee! Actually deliver the signal. */
|
||||||
handle_signal(signr, &info, &ka, oldset, regs);
|
return handle_signal(signr, &info, &ka, oldset, regs);
|
||||||
return 1;
|
|
||||||
}
|
}
|
||||||
|
|
||||||
no_signal:
|
no_signal:
|
||||||
|
|
Loading…
Reference in New Issue