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authorEric W. Biederman <ebiederm@xmission.com>2018-04-16 13:55:06 -0500
committerEric W. Biederman <ebiederm@xmission.com>2018-09-27 21:57:52 +0200
commit8b9c6b28312cc51a87055e292b11c5aa28f0c935 (patch)
tree72d2fb5a392dd97c11799884f8982ba44943588d /arch/ia64/kernel
parent795a83714526754a2b8089a0533bfef24287bcb9 (diff)
signal/ia64: Use the generic force_sigsegv in setup_frame
The ia64 handling of failure to setup a signal frame has been trying to set overlapping fields in struct siginfo since 2.3.43. The si_pid and si_uid fields are stomped when the si_addr field is set. The si_code of SI_KERNEL indicates that si_pid and si_uid should be valid, and that si_addr does not exist. Being at odds with the definition of SI_KERNEL and with nothing to indicate that this was a signal frame setup failure there is no way for userspace to know that si_addr was filled out instead. In practice failure to setup a signal frame is rare, and si_pid and si_uid are always set to 0 when si_code is SI_KERNEL so I expect no one has looked closely enough before to see this weirdness. Further the only difference between force_sigsegv_info and the generic force_sigsegv other than the return code is that force_sigsegv_info stomps the si_uid and si_pid fields. Remove the bug and simplify the code by using force_sigsegv in this case just like other architectures. Fixes: 2.3.43 Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: linux-ia64@vger.kernel.org Acked-by: Tony Luck <tony.luck@intel.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch/ia64/kernel')
-rw-r--r--arch/ia64/kernel/signal.c50
1 files changed, 12 insertions, 38 deletions
diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index d1234a5ba4c5..01fc133b2e4c 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -232,37 +232,6 @@ rbs_on_sig_stack (unsigned long bsp)
}
static long
-force_sigsegv_info (int sig, void __user *addr)
-{
- unsigned long flags;
- struct siginfo si;
-
- clear_siginfo(&si);
- if (sig == SIGSEGV) {
- /*
- * Acquiring siglock around the sa_handler-update is almost
- * certainly overkill, but this isn't a
- * performance-critical path and I'd rather play it safe
- * here than having to debug a nasty race if and when
- * something changes in kernel/signal.c that would make it
- * no longer safe to modify sa_handler without holding the
- * lock.
- */
- spin_lock_irqsave(&current->sighand->siglock, flags);
- current->sighand->action[sig - 1].sa.sa_handler = SIG_DFL;
- spin_unlock_irqrestore(&current->sighand->siglock, flags);
- }
- si.si_signo = SIGSEGV;
- si.si_errno = 0;
- si.si_code = SI_KERNEL;
- si.si_pid = task_pid_vnr(current);
- si.si_uid = from_kuid_munged(current_user_ns(), current_uid());
- si.si_addr = addr;
- force_sig_info(SIGSEGV, &si, current);
- return 1;
-}
-
-static long
setup_frame(struct ksignal *ksig, sigset_t *set, struct sigscratch *scr)
{
extern char __kernel_sigtramp[];
@@ -295,15 +264,18 @@ setup_frame(struct ksignal *ksig, sigset_t *set, struct sigscratch *scr)
* instead so we will die with SIGSEGV.
*/
check_sp = (new_sp - sizeof(*frame)) & -STACK_ALIGN;
- if (!likely(on_sig_stack(check_sp)))
- return force_sigsegv_info(ksig->sig, (void __user *)
- check_sp);
+ if (!likely(on_sig_stack(check_sp))) {
+ force_sigsegv(ksig->sig, current);
+ return 1;
+ }
}
}
frame = (void __user *) ((new_sp - sizeof(*frame)) & -STACK_ALIGN);
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
- return force_sigsegv_info(ksig->sig, frame);
+ if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) {
+ force_sigsegv(ksig->sig, current);
+ return 1;
+ }
err = __put_user(ksig->sig, &frame->arg0);
err |= __put_user(&frame->info, &frame->arg1);
@@ -317,8 +289,10 @@ setup_frame(struct ksignal *ksig, sigset_t *set, struct sigscratch *scr)
err |= __save_altstack(&frame->sc.sc_stack, scr->pt.r12);
err |= setup_sigcontext(&frame->sc, set, scr);
- if (unlikely(err))
- return force_sigsegv_info(ksig->sig, frame);
+ if (unlikely(err)) {
+ force_sigsegv(ksig->sig, current);
+ return 1;
+ }
scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */