From: "Eric W. Biederman" <ebiederm@xmission.com>
To: linux-kernel@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Oleg Nesterov <oleg@redhat.com>,
Andrei Vagin <avagin@virtuozzo.com>,
Thomas Gleixner <tglx@linutronix.de>, Greg KH <greg@kroah.com>,
Andrey Vagin <avagin@openvz.org>, Serge Hallyn <serge@hallyn.com>,
Pavel Emelyanov <xemul@virtuozzo.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Peter Zijlstra <peterz@infradead.org>, Willy Tarreau <w@1wt.eu>,
linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
Linux Containers <containers@lists.linux-foundation.org>,
Michael Kerrisk <mtk.manpages@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH 4/7] signal/mips: Document a conflict with SI_USER with SIGFPE
Date: Tue, 18 Jul 2017 09:06:48 -0500 [thread overview]
Message-ID: <20170718140651.15973-4-ebiederm@xmission.com> (raw)
In-Reply-To: <87o9shg7t7.fsf_-_@xmission.com>
Setting si_code to __SI_FAULT results in a userspace seeing
an si_code of 0. This is the same si_code as SI_USER. Posix
and common sense requires that SI_USER not be a signal specific
si_code. As such this use of 0 for the si_code is a pretty
horribly broken ABI.
This use of of __SI_FAULT is only a decade old. Which compared
to the other pieces of kernel code that has made this mistake
is almost yesterday.
This is probably worth fixing but I don't know mips well enough
to know what si_code to would be the proper one to use.
Cc: Ralf Baechle <ralf@linux-mips.org>
Ref: 948a34cf3988 ("[MIPS] Maintain si_code field properly for FP exceptions")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/mips/include/uapi/asm/siginfo.h | 7 +++++++
arch/mips/kernel/traps.c | 2 +-
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index 8069cf766603..9becfd102132 100644
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -123,4 +123,11 @@ typedef struct siginfo {
#define SI_TIMER __SI_CODE(__SI_TIMER, -3) /* sent by timer expiration */
#define SI_MESGQ __SI_CODE(__SI_MESGQ, -4) /* sent by real time mesq state change */
+/*
+ * SIGFPE si_codes
+ */
+#ifdef __KERNEL__
+#define FPE_FIXME (__SI_FAULT|0) /* Broken dup of SI_USER */
+#endif /* __KERNEL__ */
+
#endif /* _UAPI_ASM_SIGINFO_H */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index b68b4d0726d3..6c9cca9c5341 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -735,7 +735,7 @@ void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr,
else if (fcr31 & FPU_CSR_INE_X)
si.si_code = FPE_FLTRES;
else
- si.si_code = __SI_FAULT;
+ si.si_code = FPE_FIXME;
force_sig_info(SIGFPE, &si, tsk);
}
--
2.10.1
next prev parent reply other threads:[~2017-07-18 14:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87lgot2loq.fsf@xmission.com>
[not found] ` <87zid90vye.fsf_-_@xmission.com>
[not found] ` <20170615225426.GP31671@ZenIV.linux.org.uk>
[not found] ` <87poe4zrs1.fsf@xmission.com>
[not found] ` <CA+55aFxpv+gchzs7AYgSC8feAOV=B6mjFgBVm4Kx+83J2CNE-w@mail.gmail.com>
[not found] ` <87poe3vsa9.fsf@xmission.com>
[not found] ` <CALCETrX=SquyR8JZqHDNx=_FQKQo-0u9AxfdUwJs_hujVO2A-g@mail.gmail.com>
[not found] ` <87h8zfua59.fsf@xmission.com>
[not found] ` <CALCETrWPBn31Dye=81r2ZMainNOnDy5c_QxbU2uRjnJs0ie=Zg@mail.gmail.com>
[not found] ` <87r2yjsuwl.fsf@xmission.com>
[not found] ` <20170616191602.GA10675@1wt.eu>
2017-06-30 12:36 ` [PATCH 0/8] signal: Fix sending signals with siginfo Eric W. Biederman
2017-07-18 14:04 ` [PATCH v2 0/7] " Eric W. Biederman
2017-07-18 14:06 ` [PATCH 1/7] signal/alpha: Document a conflict with SI_USER for SIGTRAP Eric W. Biederman
2017-07-18 18:22 ` Richard Henderson
2017-07-18 14:06 ` [PATCH 2/7] signal/ia64: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2017-07-18 14:06 ` [PATCH 3/7] signal/sparc: " Eric W. Biederman
2017-07-18 14:06 ` Eric W. Biederman [this message]
2017-08-07 16:18 ` [PATCH 4/7] signal/mips: " Maciej W. Rozycki
2017-08-07 17:41 ` Linus Torvalds
2017-08-07 19:55 ` Ralf Baechle
2017-08-08 15:29 ` Eric W. Biederman
2017-08-08 23:19 ` Maciej W. Rozycki
2017-07-18 14:06 ` [PATCH 5/7] signal/testing: Don't look for __SI_FAULT in userspace Eric W. Biederman
2017-07-18 14:06 ` [PATCH 6/7] fcntl: Don't use ambiguous SIG_POLL si_codes Eric W. Biederman
2017-07-20 16:16 ` Oleg Nesterov
2017-07-21 2:33 ` Eric W. Biederman
2017-07-18 14:06 ` [PATCH 7/7] signal: Remove kernel interal si_code magic Eric W. Biederman
2017-07-18 16:57 ` Linus Torvalds
2017-07-18 17:27 ` Eric W. Biederman
2017-07-22 20:25 ` Simplfying copy_siginfo_to_user Eric W. Biederman
2017-07-24 17:43 ` Linus Torvalds
2017-07-24 19:01 ` Eric W. Biederman
2017-07-25 1:37 ` Al Viro
2017-07-31 16:37 ` Eric W. Biederman
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