linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org, mingo@kernel.org,
	sean.j.christopherson@intel.com, tglx@linutronix.de,
	vincenzo.frascino@arm.com, pebolle@tiscali.nl,
	linux-kernel@vger.kernel.org, hpa@zytor.com
Subject: [tip:timers/urgent] x86/vdso/32: Use 32bit syscall fallback
Date: Tue, 30 Jul 2019 15:21:24 -0700	[thread overview]
Message-ID: <tip-d2f5d3fa26196183adb44a413c44caa9872275b4@git.kernel.org> (raw)
In-Reply-To: <20190728131648.879156507@linutronix.de>

Commit-ID:  d2f5d3fa26196183adb44a413c44caa9872275b4
Gitweb:     https://git.kernel.org/tip/d2f5d3fa26196183adb44a413c44caa9872275b4
Author:     Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Sun, 28 Jul 2019 15:12:55 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 31 Jul 2019 00:09:10 +0200

x86/vdso/32: Use 32bit syscall fallback

The generic VDSO implementation uses the Y2038 safe clock_gettime64() and
clock_getres_time64() syscalls as fallback for 32bit VDSO. This breaks
seccomp setups because these syscalls might be not (yet) allowed.

Implement the 32bit variants which use the legacy syscalls and select the
variant in the core library.

The 64bit time variants are not removed because they are required for the
time64 based vdso accessors.

Fixes: 7ac870747988 ("x86/vdso: Switch to generic vDSO implementation")
Reported-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20190728131648.879156507@linutronix.de

---
 arch/x86/include/asm/vdso/gettimeofday.h | 36 ++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h
index ae91429129a6..ba71a63cdac4 100644
--- a/arch/x86/include/asm/vdso/gettimeofday.h
+++ b/arch/x86/include/asm/vdso/gettimeofday.h
@@ -96,6 +96,8 @@ long clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
 
 #else
 
+#define VDSO_HAS_32BIT_FALLBACK	1
+
 static __always_inline
 long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
 {
@@ -113,6 +115,23 @@ long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
 	return ret;
 }
 
+static __always_inline
+long clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
+{
+	long ret;
+
+	asm (
+		"mov %%ebx, %%edx \n"
+		"mov %[clock], %%ebx \n"
+		"call __kernel_vsyscall \n"
+		"mov %%edx, %%ebx \n"
+		: "=a" (ret), "=m" (*_ts)
+		: "0" (__NR_clock_gettime), [clock] "g" (_clkid), "c" (_ts)
+		: "edx");
+
+	return ret;
+}
+
 static __always_inline
 long gettimeofday_fallback(struct __kernel_old_timeval *_tv,
 			   struct timezone *_tz)
@@ -148,6 +167,23 @@ clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
 	return ret;
 }
 
+static __always_inline
+long clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
+{
+	long ret;
+
+	asm (
+		"mov %%ebx, %%edx \n"
+		"mov %[clock], %%ebx \n"
+		"call __kernel_vsyscall \n"
+		"mov %%edx, %%ebx \n"
+		: "=a" (ret), "=m" (*_ts)
+		: "0" (__NR_clock_getres), [clock] "g" (_clkid), "c" (_ts)
+		: "edx");
+
+	return ret;
+}
+
 #endif
 
 #ifdef CONFIG_PARAVIRT_CLOCK

  parent reply	other threads:[~2019-07-30 22:21 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-28 13:12 [patch 0/5] lib/vdso, x86/vdso: Fix fallout from generic VDSO conversion Thomas Gleixner
2019-07-28 13:12 ` [patch 1/5] lib/vdso/32: Remove inconsistent NULL pointer checks Thomas Gleixner
2019-07-28 14:33   ` Andy Lutomirski
2019-07-28 14:42     ` Thomas Gleixner
2019-07-28 15:30   ` Vincenzo Frascino
2019-07-29 14:52   ` Sean Christopherson
2019-07-30 22:19   ` [tip:timers/urgent] " tip-bot for Thomas Gleixner
2019-07-28 13:12 ` [patch 2/5] lib/vdso: Move fallback invocation to the callers Thomas Gleixner
2019-07-28 14:37   ` Andy Lutomirski
2019-07-28 15:31   ` Vincenzo Frascino
2019-07-30 22:19   ` [tip:timers/urgent] " tip-bot for Thomas Gleixner
2019-07-28 13:12 ` [patch 3/5] lib/vdso/32: Provide legacy syscall fallbacks Thomas Gleixner
2019-07-28 14:39   ` Andy Lutomirski
2019-07-28 15:33   ` Vincenzo Frascino
2019-07-29 14:48   ` Sean Christopherson
2019-07-30  9:38     ` [patch V2 " Thomas Gleixner
2019-07-30 14:28       ` Sean Christopherson
2019-07-30 20:09       ` Andy Lutomirski
2019-07-30 20:14         ` Thomas Gleixner
2019-07-30 22:20       ` [tip:timers/urgent] " tip-bot for Thomas Gleixner
2019-07-28 13:12 ` [patch 4/5] x86/vdso/32: Use 32bit syscall fallback Thomas Gleixner
2019-07-28 14:50   ` Andy Lutomirski
2019-07-29 11:23   ` Vincenzo Frascino
2019-07-29 14:51   ` Sean Christopherson
2019-07-30 22:21   ` tip-bot for Thomas Gleixner [this message]
2019-07-28 13:12 ` [patch 5/5] arm64: compat: vdso: Use legacy syscalls as fallback Thomas Gleixner
2019-07-28 15:35   ` Vincenzo Frascino
2019-07-30 22:22   ` [tip:timers/urgent] " tip-bot for Thomas Gleixner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=tip-d2f5d3fa26196183adb44a413c44caa9872275b4@git.kernel.org \
    --to=tipbot@zytor.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tip-commits@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=mingo@kernel.org \
    --cc=pebolle@tiscali.nl \
    --cc=sean.j.christopherson@intel.com \
    --cc=tglx@linutronix.de \
    --cc=vincenzo.frascino@arm.com \
    --subject='Re: [tip:timers/urgent] x86/vdso/32: Use 32bit syscall fallback' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox