From: "tip-bot2 for Dmitry Safonov" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Andrei Vagin <avagin@gmail.com>, Dmitry Safonov <dima@arista.com>,
Thomas Gleixner <tglx@linutronix.de>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: timers/core] x86/vdso: Handle faults on timens page
Date: Tue, 14 Jan 2020 13:02:15 -0000 [thread overview]
Message-ID: <157900693539.396.15559667078131565148.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20191112012724.250792-25-dima@arista.com>
The following commit has been merged into the timers/core branch of tip:
Commit-ID: af34ebeb866fafc0a9a09dda51c52ccec007ace0
Gitweb: https://git.kernel.org/tip/af34ebeb866fafc0a9a09dda51c52ccec007ace0
Author: Dmitry Safonov <dima@arista.com>
AuthorDate: Tue, 12 Nov 2019 01:27:13
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Tue, 14 Jan 2020 12:20:58 +01:00
x86/vdso: Handle faults on timens page
If a task belongs to a time namespace then the VVAR page which contains
the system wide VDSO data is replaced with a namespace specific page
which has the same layout as the VVAR page.
Co-developed-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20191112012724.250792-25-dima@arista.com
---
arch/x86/entry/vdso/vma.c | 54 ++++++++++++++++++++++++++++++++++++--
mm/mmap.c | 2 +-
2 files changed, 54 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 04e3498..e5f3361 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -14,11 +14,14 @@
#include <linux/elf.h>
#include <linux/cpu.h>
#include <linux/ptrace.h>
+#include <linux/time_namespace.h>
+
#include <asm/pvclock.h>
#include <asm/vgtod.h>
#include <asm/proto.h>
#include <asm/vdso.h>
#include <asm/vvar.h>
+#include <asm/tlb.h>
#include <asm/page.h>
#include <asm/desc.h>
#include <asm/cpufeature.h>
@@ -107,10 +110,36 @@ static int vvar_mremap(const struct vm_special_mapping *sm,
return 0;
}
+#ifdef CONFIG_TIME_NS
+static struct page *find_timens_vvar_page(struct vm_area_struct *vma)
+{
+ if (likely(vma->vm_mm == current->mm))
+ return current->nsproxy->time_ns->vvar_page;
+
+ /*
+ * VM_PFNMAP | VM_IO protect .fault() handler from being called
+ * through interfaces like /proc/$pid/mem or
+ * process_vm_{readv,writev}() as long as there's no .access()
+ * in special_mapping_vmops().
+ * For more details check_vma_flags() and __access_remote_vm()
+ */
+
+ WARN(1, "vvar_page accessed remotely");
+
+ return NULL;
+}
+#else
+static inline struct page *find_timens_vvar_page(struct vm_area_struct *vma)
+{
+ return NULL;
+}
+#endif
+
static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
struct vm_area_struct *vma, struct vm_fault *vmf)
{
const struct vdso_image *image = vma->vm_mm->context.vdso_image;
+ unsigned long pfn;
long sym_offset;
if (!image)
@@ -130,8 +159,21 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
return VM_FAULT_SIGBUS;
if (sym_offset == image->sym_vvar_page) {
- return vmf_insert_pfn(vma, vmf->address,
- __pa_symbol(&__vvar_page) >> PAGE_SHIFT);
+ struct page *timens_page = find_timens_vvar_page(vma);
+
+ pfn = __pa_symbol(&__vvar_page) >> PAGE_SHIFT;
+
+ /*
+ * If a task belongs to a time namespace then a namespace
+ * specific VVAR is mapped with the sym_vvar_page offset and
+ * the real VVAR page is mapped with the sym_timens_page
+ * offset.
+ * See also the comment near timens_setup_vdso_data().
+ */
+ if (timens_page)
+ pfn = page_to_pfn(timens_page);
+
+ return vmf_insert_pfn(vma, vmf->address, pfn);
} else if (sym_offset == image->sym_pvclock_page) {
struct pvclock_vsyscall_time_info *pvti =
pvclock_get_pvti_cpu0_va();
@@ -146,6 +188,14 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
if (tsc_pg && vclock_was_used(VCLOCK_HVCLOCK))
return vmf_insert_pfn(vma, vmf->address,
virt_to_phys(tsc_pg) >> PAGE_SHIFT);
+ } else if (sym_offset == image->sym_timens_page) {
+ struct page *timens_page = find_timens_vvar_page(vma);
+
+ if (!timens_page)
+ return VM_FAULT_SIGBUS;
+
+ pfn = __pa_symbol(&__vvar_page) >> PAGE_SHIFT;
+ return vmf_insert_pfn(vma, vmf->address, pfn);
}
return VM_FAULT_SIGBUS;
diff --git a/mm/mmap.c b/mm/mmap.c
index 9c64852..60c17d3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3342,6 +3342,8 @@ static const struct vm_operations_struct special_mapping_vmops = {
.fault = special_mapping_fault,
.mremap = special_mapping_mremap,
.name = special_mapping_name,
+ /* vDSO code relies that VVAR can't be accessed remotely */
+ .access = NULL,
};
static const struct vm_operations_struct legacy_special_mapping_vmops = {
next prev parent reply other threads:[~2020-01-14 13:02 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 1:26 [PATCHv8 00/34] kernel: Introduce Time Namespace Dmitry Safonov
2019-11-12 1:26 ` [PATCHv8 01/34] lib/vdso: Add unlikely() hint into vdso_read_begin() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 02/34] lib/vdso: make do_hres and do_coarse as __always_inline Dmitry Safonov
2020-01-10 9:45 ` Vincenzo Frascino
2020-01-10 11:42 ` Thomas Gleixner
2020-01-10 11:47 ` Vincenzo Frascino
2020-01-10 12:02 ` Thomas Gleixner
2020-01-10 12:18 ` Vincenzo Frascino
2020-01-13 5:27 ` Andrei Vagin
2020-01-13 19:09 ` [tip: timers/core] lib/vdso: Mark do_hres() and do_coarse() " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 03/34] ns: Introduce Time Namespace Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2020-01-27 14:12 ` [PATCHv8 03/34] " Dmitry Vyukov
2020-01-27 14:19 ` Dmitry Safonov
2020-02-17 14:20 ` Time Namespaces: CLONE_NEWTIME and clone3()? Michael Kerrisk
2020-02-17 14:59 ` Christian Brauner
2020-02-17 21:47 ` Michael Kerrisk (man-pages)
2020-02-17 23:03 ` Christian Brauner
2020-02-17 23:29 ` Thomas Gleixner
2020-02-18 2:37 ` Eric W. Biederman
2020-02-18 17:11 ` Adrian Reber
2020-02-18 17:26 ` Christian Brauner
2019-11-12 1:26 ` [PATCHv8 04/34] time: Add timens_offsets to be used for tasks in timens Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] time: Add timens_offsets to be used for tasks in time namespace tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 05/34] posix-clocks: Rename the clock_get() callback to clock_get_timespec() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 06/34] posix-clocks: Rename .clock_get_timespec() callbacks accordingly Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 07/34] alarmtimer: Rename gettime() callback to get_ktime() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 08/34] alarmtimer: Provide get_timespec() callback Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 09/34] posix-clocks: Introduce clock_get_ktime() callback Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:26 ` [PATCHv8 10/34] posix-timers: Use clock_get_ktime() in common_timer_get() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 11/34] posix-clocks: Wire up clock_gettime() with timens offsets Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 12/34] kernel: Add do_timens_ktime_to_host() helper Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] time: " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 13/34] timerfd: Make timerfd_settime() time namespace aware Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 14/34] posix-timers: Make timer_settime() " Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 15/34] alarmtimer: Make nanosleep " Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] alarmtimer: Make nanosleep() " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 16/34] hrtimers: Prepare hrtimer_nanosleep() for time namespaces Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 17/34] posix-timers: Make clock_nanosleep() time namespace aware Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 18/34] fs/proc: Respect boottime inside time namespace for /proc/uptime Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 19/34] x86/vdso: Restrict splitting VVAR VMA Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 20/34] lib/vdso: Prepare for time namespace support Dmitry Safonov
2020-01-12 10:32 ` Thomas Gleixner
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-01-14 13:02 ` tip-bot2 for Thomas Gleixner
2019-11-12 1:27 ` [PATCHv8 21/34] x86/vdso: Provide vdso_data offset on vvar_page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 22/34] x86/vdso: Add timens page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] x86/vdso: Add time napespace page tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 23/34] time: Allocate per-timens vvar page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 24/34] x86/vdso: Handle faults on timens page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov [this message]
2019-11-12 1:27 ` [PATCHv8 25/34] x86/vdso: On timens page fault prefault also VVAR page Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 26/34] x86/vdso: Zap vvar pages on switch a time namspace Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] x86/vdso: Zap vvar pages when switching to a time namespace tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 27/34] fs/proc: Introduce /proc/pid/timens_offsets Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 28/34] selftests/timens: Add Time Namespace test for supported clocks Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 29/34] selftests/timens: Add a test for timerfd Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 30/34] selftests/timens: Add a test for clock_nanosleep() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 31/34] selftests/timens: Add procfs selftest Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Dmitry Safonov
2020-01-14 13:02 ` tip-bot2 for Dmitry Safonov
2019-11-12 1:27 ` [PATCHv8 32/34] selftests/timens: Add timer offsets test Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 33/34] selftests/timens: Add a simple perf test for clock_gettime() Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-12 1:27 ` [PATCHv8 34/34] selftests/timens: Check for right timens offsets after fork and exec Dmitry Safonov
2020-01-13 19:09 ` [tip: timers/core] " tip-bot2 for Andrei Vagin
2020-01-14 13:02 ` tip-bot2 for Andrei Vagin
2019-11-21 18:05 ` [PATCHv8 00/34] kernel: Introduce Time Namespace Andrei Vagin
2019-12-11 20:38 ` Dmitry Safonov
2020-01-09 21:09 ` Thomas Gleixner
2020-01-10 9:52 ` Vincenzo Frascino
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