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Subject[PATCH 4.19 033/639] signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn
Date
From: Eric W. Biederman <ebiederm@xmission.com>

[ Upstream commit b92adb74adde62d9a9780ff2977d63dcb21aeaa6 ]

The ia64 handling of failure to return from a signal frame has been trying
to set overlapping fields in struct siginfo since 2.3.43. The si_code
corresponds to the fields that were stomped (not the field that is
actually written), so I can not imagine a piece of userspace code
making sense of the signal frame if it looks closely.

In practice failure to return from a signal frame is a rare event that
almost never happens. Someone using an alternate signal stack to
recover and looking in detail is even more rare. So I presume no one
has ever noticed and reported this ia64 nonsense.

Sort this out by causing ia64 to use force_sig(SIGSEGV) 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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/ia64/kernel/signal.c | 10 +---------
1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/arch/ia64/kernel/signal.c b/arch/ia64/kernel/signal.c
index 01fc133b2e4c8..9a960829a01d9 100644
--- a/arch/ia64/kernel/signal.c
+++ b/arch/ia64/kernel/signal.c
@@ -110,7 +110,6 @@ ia64_rt_sigreturn (struct sigscratch *scr)
{
extern char ia64_strace_leave_kernel, ia64_leave_kernel;
struct sigcontext __user *sc;
- struct siginfo si;
sigset_t set;
long retval;

@@ -153,14 +152,7 @@ ia64_rt_sigreturn (struct sigscratch *scr)
return retval;

give_sigsegv:
- clear_siginfo(&si);
- 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 = sc;
- force_sig_info(SIGSEGV, &si, current);
+ force_sig(SIGSEGV, current);
return retval;
}

--
2.20.1


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