From: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Andrei Vagin <avagin-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>,
Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
Greg KH <greg-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>,
Andrey Vagin <avagin-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>,
Serge Hallyn <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>,
Pavel Emelyanov <xemul-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>,
Cyrill Gorcunov
<gorcunov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>,
Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
Willy Tarreau <w@1wt.eu>,
linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Linux Containers
<containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>,
Michael Kerrisk
<mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"Eric W. Biederman"
<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
Thiemo Seufer <ths-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>,
Ralf Baechle <ralf-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
Subject: [PATCH 4/8] signal/mips: Document a conflict with SI_USER with SIGFPE
Date: Fri, 30 Jun 2017 07:39:02 -0500 [thread overview]
Message-ID: <20170630123906.8865-4-ebiederm@xmission.com> (raw)
In-Reply-To: <87efu22set.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
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: Thiemo Seufer <ths-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
Cc: Ralf Baechle <ralf-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
Ref: 948a34cf3988 ("[MIPS] Maintain si_code field properly for FP exceptions")
Signed-off-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
---
arch/mips/include/uapi/asm/siginfo.h | 5 +++++
arch/mips/kernel/traps.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index 8069cf766603..0d80df888325 100644
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -123,4 +123,9 @@ 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
+ */
+#define FPE_FIXME (__SI_FAULT|0) /* Broken dup of SI_USER */
+
#endif /* _UAPI_ASM_SIGINFO_H */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 9681b5877140..477dfca99147 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -732,7 +732,7 @@ 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:[~2017-06-30 12:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <87efu22set.fsf@xmission.com>
2017-06-30 12:38 ` [PATCH 1/8] signal/alpha: Document a conflict with SI_USER for SIGTRAP Eric W. Biederman
2017-07-02 14:13 ` Helge Deller
[not found] ` <20170702141320.GA32254-PwtjyNU/e7vkVFMGpb/cPg@public.gmane.org>
2017-07-14 10:59 ` Eric W. Biederman
2017-07-17 8:14 ` Michael Cree
2017-07-18 13:37 ` Eric W. Biederman
2017-06-30 12:39 ` [PATCH 2/8] signal/ia64: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2017-06-30 12:39 ` [PATCH 3/8] signal/sparc: " Eric W. Biederman
2017-06-30 16:45 ` David Miller
[not found] ` <20170630.124505.736865959393416284.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2017-06-30 18:13 ` Eric W. Biederman
[not found] ` <8737ahwdgr.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-18 13:43 ` Eric W. Biederman
[not found] ` <87efu22set.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-06-30 12:39 ` Eric W. Biederman [this message]
2017-06-30 12:39 ` [PATCH 5/8] signal/testing: Don't look for __SI_FAULT in userspace Eric W. Biederman
2017-06-30 12:39 ` [PATCH 6/8] signal/x86: Fix SIGSYS handling in copy_siginfo_to_user32 Eric W. Biederman
2017-06-30 12:39 ` [PATCH 7/8] fcntl: Don't use ambiguous SIG_POLL si_codes Eric W. Biederman
2017-06-30 12:39 ` [PATCH 8/8] signal: Remove kernel interal si_code magic Eric W. Biederman
[not found] ` <20170630123906.8865-8-ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-07-12 22:36 ` Andrei Vagin
2017-07-12 23:08 ` Eric W. Biederman
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