* [PATCHv5 1/6] x86/vdso: unmap vdso blob on vvar mapping failure
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
@ 2016-09-05 13:33 ` Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 2/6] x86/vdso: replace calculate_addr in map_vdso() with addr Dmitry Safonov
` (5 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-05 13:33 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, luto, oleg, tglx, hpa, mingo, linux-mm, x86,
gorcunov, xemul, Dmitry Safonov
If remapping of vDSO blob failed on vvar mapping,
we need to unmap previously mapped vDSO blob.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/vdso/vma.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index f840766659a8..3bab6ba3ffc5 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -238,12 +238,14 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
- goto up_fail;
+ do_munmap(mm, text_start, image->size);
}
up_fail:
- if (ret)
+ if (ret) {
current->mm->context.vdso = NULL;
+ current->mm->context.vdso_image = NULL;
+ }
up_write(&mm->mmap_sem);
return ret;
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCHv5 2/6] x86/vdso: replace calculate_addr in map_vdso() with addr
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 1/6] x86/vdso: unmap vdso blob on vvar mapping failure Dmitry Safonov
@ 2016-09-05 13:33 ` Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_* Dmitry Safonov
` (4 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-05 13:33 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, luto, oleg, tglx, hpa, mingo, linux-mm, x86,
gorcunov, xemul, Dmitry Safonov
That will allow to specify address where to map vDSO blob.
For the randomized vDSO mappings introduce map_vdso_randomized()
which will simplify calls to map_vdso.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/vdso/vma.c | 30 +++++++++++++++++-------------
1 file changed, 17 insertions(+), 13 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 3bab6ba3ffc5..5bcb25a9e573 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -176,11 +176,16 @@ static int vvar_fault(const struct vm_special_mapping *sm,
return VM_FAULT_SIGBUS;
}
-static int map_vdso(const struct vdso_image *image, bool calculate_addr)
+/*
+ * Add vdso and vvar mappings to current process.
+ * @image - blob to map
+ * @addr - request a specific address (zero to map at free addr)
+ */
+static int map_vdso(const struct vdso_image *image, unsigned long addr)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- unsigned long addr, text_start;
+ unsigned long text_start;
int ret = 0;
static const struct vm_special_mapping vdso_mapping = {
@@ -193,13 +198,6 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
.fault = vvar_fault,
};
- if (calculate_addr) {
- addr = vdso_addr(current->mm->start_stack,
- image->size - image->sym_vvar_start);
- } else {
- addr = 0;
- }
-
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
@@ -251,13 +249,20 @@ up_fail:
return ret;
}
+static int map_vdso_randomized(const struct vdso_image *image)
+{
+ unsigned long addr = vdso_addr(current->mm->start_stack,
+ image->size - image->sym_vvar_start);
+ return map_vdso(image, addr);
+}
+
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
static int load_vdso32(void)
{
if (vdso32_enabled != 1) /* Other values all mean "disabled" */
return 0;
- return map_vdso(&vdso_image_32, false);
+ return map_vdso(&vdso_image_32, 0);
}
#endif
@@ -267,7 +272,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
if (!vdso64_enabled)
return 0;
- return map_vdso(&vdso_image_64, true);
+ return map_vdso_randomized(&vdso_image_64);
}
#ifdef CONFIG_COMPAT
@@ -278,8 +283,7 @@ int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
if (test_thread_flag(TIF_X32)) {
if (!vdso64_enabled)
return 0;
-
- return map_vdso(&vdso_image_x32, true);
+ return map_vdso_randomized(&vdso_image_x32);
}
#endif
#ifdef CONFIG_IA32_EMULATION
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCHv5 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_*
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 1/6] x86/vdso: unmap vdso blob on vvar mapping failure Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 2/6] x86/vdso: replace calculate_addr in map_vdso() with addr Dmitry Safonov
@ 2016-09-05 13:33 ` Dmitry Safonov
2016-09-05 17:01 ` Andy Lutomirski
2016-09-05 13:33 ` [PATCHv5 4/6] x86/coredump: use pr_reg size, rather that TIF_IA32 flag Dmitry Safonov
` (3 subsequent siblings)
6 siblings, 1 reply; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-05 13:33 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, luto, oleg, tglx, hpa, mingo, linux-mm, x86,
gorcunov, xemul, Dmitry Safonov
Add API to change vdso blob type with arch_prctl.
As this is usefull only by needs of CRIU, expose
this interface under CONFIG_CHECKPOINT_RESTORE.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
---
arch/x86/entry/vdso/vma.c | 45 ++++++++++++++++++++++++++++++---------
arch/x86/include/asm/vdso.h | 2 ++
arch/x86/include/uapi/asm/prctl.h | 6 ++++++
arch/x86/kernel/process_64.c | 25 ++++++++++++++++++++++
include/linux/mm.h | 2 ++
mm/mmap.c | 8 +++++++
6 files changed, 78 insertions(+), 10 deletions(-)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 5bcb25a9e573..4459e73e234d 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -176,6 +176,16 @@ static int vvar_fault(const struct vm_special_mapping *sm,
return VM_FAULT_SIGBUS;
}
+static const struct vm_special_mapping vdso_mapping = {
+ .name = "[vdso]",
+ .fault = vdso_fault,
+ .mremap = vdso_mremap,
+};
+static const struct vm_special_mapping vvar_mapping = {
+ .name = "[vvar]",
+ .fault = vvar_fault,
+};
+
/*
* Add vdso and vvar mappings to current process.
* @image - blob to map
@@ -188,16 +198,6 @@ static int map_vdso(const struct vdso_image *image, unsigned long addr)
unsigned long text_start;
int ret = 0;
- static const struct vm_special_mapping vdso_mapping = {
- .name = "[vdso]",
- .fault = vdso_fault,
- .mremap = vdso_mremap,
- };
- static const struct vm_special_mapping vvar_mapping = {
- .name = "[vvar]",
- .fault = vvar_fault,
- };
-
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
@@ -256,6 +256,31 @@ static int map_vdso_randomized(const struct vdso_image *image)
return map_vdso(image, addr);
}
+int map_vdso_once(const struct vdso_image *image, unsigned long addr)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+
+ down_write(&mm->mmap_sem);
+ /*
+ * Check if we have already mapped vdso blob - fail to prevent
+ * abusing from userspace install_speciall_mapping, which may
+ * not do accounting and rlimit right.
+ * We could search vma near context.vdso, but it's a slowpath,
+ * so let's explicitely check all VMAs to be completely sure.
+ */
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ if (vma_is_special_mapping(vma, &vdso_mapping) ||
+ vma_is_special_mapping(vma, &vvar_mapping)) {
+ up_write(&mm->mmap_sem);
+ return -EEXIST;
+ }
+ }
+ up_write(&mm->mmap_sem);
+
+ return map_vdso(image, addr);
+}
+
#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
static int load_vdso32(void)
{
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index 43dc55be524e..2444189cbe28 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -41,6 +41,8 @@ extern const struct vdso_image vdso_image_32;
extern void __init init_vdso_image(const struct vdso_image *image);
+extern int map_vdso_once(const struct vdso_image *image, unsigned long addr);
+
#endif /* __ASSEMBLER__ */
#endif /* _ASM_X86_VDSO_H */
diff --git a/arch/x86/include/uapi/asm/prctl.h b/arch/x86/include/uapi/asm/prctl.h
index 3ac5032fae09..ae135de547f5 100644
--- a/arch/x86/include/uapi/asm/prctl.h
+++ b/arch/x86/include/uapi/asm/prctl.h
@@ -6,4 +6,10 @@
#define ARCH_GET_FS 0x1003
#define ARCH_GET_GS 0x1004
+#ifdef CONFIG_CHECKPOINT_RESTORE
+# define ARCH_MAP_VDSO_X32 0x2001
+# define ARCH_MAP_VDSO_32 0x2002
+# define ARCH_MAP_VDSO_64 0x2003
+#endif
+
#endif /* _ASM_X86_PRCTL_H */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 63236d8f84bf..f240a465920b 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -49,6 +49,7 @@
#include <asm/debugreg.h>
#include <asm/switch_to.h>
#include <asm/xen/hypervisor.h>
+#include <asm/vdso.h>
asmlinkage extern void ret_from_fork(void);
@@ -524,6 +525,17 @@ void set_personality_ia32(bool x32)
}
EXPORT_SYMBOL_GPL(set_personality_ia32);
+static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr)
+{
+ int ret;
+
+ ret = map_vdso_once(image, addr);
+ if (ret)
+ return ret;
+
+ return (long)image->size;
+}
+
long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
{
int ret = 0;
@@ -577,6 +589,19 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
break;
}
+#ifdef CONFIG_CHECKPOINT_RESTORE
+#ifdef CONFIG_X86_X32
+ case ARCH_MAP_VDSO_X32:
+ return prctl_map_vdso(&vdso_image_x32, addr);
+#endif
+#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
+ case ARCH_MAP_VDSO_32:
+ return prctl_map_vdso(&vdso_image_32, addr);
+#endif
+ case ARCH_MAP_VDSO_64:
+ return prctl_map_vdso(&vdso_image_64, addr);
+#endif
+
default:
ret = -EINVAL;
break;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ef815b9cd426..5f14534f0c90 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2019,6 +2019,8 @@ extern struct file *get_task_exe_file(struct task_struct *task);
extern bool may_expand_vm(struct mm_struct *, vm_flags_t, unsigned long npages);
extern void vm_stat_account(struct mm_struct *, vm_flags_t, long npages);
+extern bool vma_is_special_mapping(const struct vm_area_struct *vma,
+ const struct vm_special_mapping *sm);
extern struct vm_area_struct *_install_special_mapping(struct mm_struct *mm,
unsigned long addr, unsigned long len,
unsigned long flags,
diff --git a/mm/mmap.c b/mm/mmap.c
index ca9d91bca0d6..6373ebd358c0 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3063,6 +3063,14 @@ out:
return ERR_PTR(ret);
}
+bool vma_is_special_mapping(const struct vm_area_struct *vma,
+ const struct vm_special_mapping *sm)
+{
+ return vma->vm_private_data == sm &&
+ (vma->vm_ops == &special_mapping_vmops ||
+ vma->vm_ops == &legacy_special_mapping_vmops);
+}
+
/*
* Called with mm->mmap_sem held for writing.
* Insert a new vma covering the given region, with the given flags.
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCHv5 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_*
2016-09-05 13:33 ` [PATCHv5 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_* Dmitry Safonov
@ 2016-09-05 17:01 ` Andy Lutomirski
0 siblings, 0 replies; 9+ messages in thread
From: Andy Lutomirski @ 2016-09-05 17:01 UTC (permalink / raw)
To: Dmitry Safonov
Cc: linux-kernel, Dmitry Safonov, Andrew Lutomirski, Oleg Nesterov,
Thomas Gleixner, H. Peter Anvin, Ingo Molnar, linux-mm, X86 ML,
Cyrill Gorcunov, Pavel Emelyanov
On Mon, Sep 5, 2016 at 6:33 AM, Dmitry Safonov <dsafonov@virtuozzo.com> wrote:
> Add API to change vdso blob type with arch_prctl.
> As this is usefull only by needs of CRIU, expose
> this interface under CONFIG_CHECKPOINT_RESTORE.
Acked-by: Andy Lutomirski <luto@kernel.org>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCHv5 4/6] x86/coredump: use pr_reg size, rather that TIF_IA32 flag
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
` (2 preceding siblings ...)
2016-09-05 13:33 ` [PATCHv5 3/6] x86/arch_prctl/vdso: add ARCH_MAP_VDSO_* Dmitry Safonov
@ 2016-09-05 13:33 ` Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32) Dmitry Safonov
` (2 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-05 13:33 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, luto, oleg, tglx, hpa, mingo, linux-mm, x86,
gorcunov, xemul, Dmitry Safonov
Killed PR_REG_SIZE and PR_REG_PTR macro as we can get regset size
from regset view.
I wish I could also kill PRSTATUS_SIZE nicely.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
---
arch/x86/include/asm/compat.h | 8 ++++----
fs/binfmt_elf.c | 23 ++++++++---------------
2 files changed, 12 insertions(+), 19 deletions(-)
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index a18806165fe4..03d269bed941 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -275,10 +275,10 @@ struct compat_shmid64_ds {
#ifdef CONFIG_X86_X32_ABI
typedef struct user_regs_struct compat_elf_gregset_t;
-#define PR_REG_SIZE(S) (test_thread_flag(TIF_IA32) ? 68 : 216)
-#define PRSTATUS_SIZE(S) (test_thread_flag(TIF_IA32) ? 144 : 296)
-#define SET_PR_FPVALID(S,V) \
- do { *(int *) (((void *) &((S)->pr_reg)) + PR_REG_SIZE(0)) = (V); } \
+/* Full regset -- prstatus on x32, otherwise on ia32 */
+#define PRSTATUS_SIZE(S, R) (R != sizeof(S.pr_reg) ? 144 : 296)
+#define SET_PR_FPVALID(S, V, R) \
+ do { *(int *) (((void *) &((S)->pr_reg)) + R) = (V); } \
while (0)
#define COMPAT_USE_64BIT_TIME \
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index e5495f37c6ed..2472af2798c7 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1624,20 +1624,12 @@ static void do_thread_regset_writeback(struct task_struct *task,
regset->writeback(task, regset, 1);
}
-#ifndef PR_REG_SIZE
-#define PR_REG_SIZE(S) sizeof(S)
-#endif
-
#ifndef PRSTATUS_SIZE
-#define PRSTATUS_SIZE(S) sizeof(S)
-#endif
-
-#ifndef PR_REG_PTR
-#define PR_REG_PTR(S) (&((S)->pr_reg))
+#define PRSTATUS_SIZE(S, R) sizeof(S)
#endif
#ifndef SET_PR_FPVALID
-#define SET_PR_FPVALID(S, V) ((S)->pr_fpvalid = (V))
+#define SET_PR_FPVALID(S, V, R) ((S)->pr_fpvalid = (V))
#endif
static int fill_thread_core_info(struct elf_thread_core_info *t,
@@ -1645,6 +1637,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
long signr, size_t *total)
{
unsigned int i;
+ unsigned int regset_size = view->regsets[0].n * view->regsets[0].size;
/*
* NT_PRSTATUS is the one special case, because the regset data
@@ -1653,12 +1646,11 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
* We assume that regset 0 is NT_PRSTATUS.
*/
fill_prstatus(&t->prstatus, t->task, signr);
- (void) view->regsets[0].get(t->task, &view->regsets[0],
- 0, PR_REG_SIZE(t->prstatus.pr_reg),
- PR_REG_PTR(&t->prstatus), NULL);
+ (void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset_size,
+ &t->prstatus.pr_reg, NULL);
fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
- PRSTATUS_SIZE(t->prstatus), &t->prstatus);
+ PRSTATUS_SIZE(t->prstatus, regset_size), &t->prstatus);
*total += notesize(&t->notes[0]);
do_thread_regset_writeback(t->task, &view->regsets[0]);
@@ -1688,7 +1680,8 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
regset->core_note_type,
size, data);
else {
- SET_PR_FPVALID(&t->prstatus, 1);
+ SET_PR_FPVALID(&t->prstatus,
+ 1, regset_size);
fill_note(&t->notes[i], "CORE",
NT_PRFPREG, size, data);
}
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCHv5 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32)
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
` (3 preceding siblings ...)
2016-09-05 13:33 ` [PATCHv5 4/6] x86/coredump: use pr_reg size, rather that TIF_IA32 flag Dmitry Safonov
@ 2016-09-05 13:33 ` Dmitry Safonov
2016-09-05 13:33 ` [PATCHv5 6/6] x86/signal: add SA_{X32,IA32}_ABI sa_flags Dmitry Safonov
2016-09-14 15:56 ` [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
6 siblings, 0 replies; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-05 13:33 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, luto, oleg, tglx, hpa, mingo, linux-mm, x86,
gorcunov, xemul, Dmitry Safonov, Pedro Alves
As the task isn't executing at the moment of {GET,SET}REGS,
return regset that corresponds to code selector, rather than
value of TIF_IA32 flag.
I.e. if we ptrace i386 elf binary that has just changed it's
code selector to __USER_CS, than GET_REGS will return
full x86_64 register set.
Note, that this will work only if application has changed it's CS.
If the application does 32-bit syscall with __USER_CS, ptrace
will still return 64-bit register set. Which might be still confusing
for tools that expect TS_COMPACT to be exposed [1, 2].
So this this change should make PTRACE_GETREGSET more reliable and
this will be another step to drop TIF_{IA32,X32} flags.
[1]: https://sourceforge.net/p/strace/mailman/message/30471411/
[2]: https://lkml.org/lkml/2012/1/18/320
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
---
arch/x86/kernel/ptrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index f79576a541ff..ad0bab8fc594 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -1358,7 +1358,7 @@ void update_regset_xstate_info(unsigned int size, u64 xstate_mask)
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_IA32_EMULATION
- if (test_tsk_thread_flag(task, TIF_IA32))
+ if (!user_64bit_mode(task_pt_regs(task)))
#endif
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
return &user_x86_32_view;
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCHv5 6/6] x86/signal: add SA_{X32,IA32}_ABI sa_flags
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
` (4 preceding siblings ...)
2016-09-05 13:33 ` [PATCHv5 5/6] x86/ptrace: down with test_thread_flag(TIF_IA32) Dmitry Safonov
@ 2016-09-05 13:33 ` Dmitry Safonov
2016-09-14 15:56 ` [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
6 siblings, 0 replies; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-05 13:33 UTC (permalink / raw)
To: linux-kernel
Cc: 0x7f454c46, luto, oleg, tglx, hpa, mingo, linux-mm, x86,
gorcunov, xemul, Dmitry Safonov
Introduce new flags that defines which ABI to use on creating sigframe.
Those flags kernel will set according to sigaction syscall ABI,
which set handler for the signal being delivered.
So that will drop the dependency on TIF_IA32/TIF_X32 flags on signal deliver.
Those flags will be used only under CONFIG_COMPAT.
Similar way ARM uses sa_flags to differ in which mode deliver signal
for 26-bit applications (look at SA_THIRYTWO).
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: x86@kernel.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/ia32/ia32_signal.c | 2 +-
arch/x86/include/asm/fpu/signal.h | 6 ++++++
arch/x86/include/asm/signal.h | 4 ++++
arch/x86/kernel/signal.c | 20 +++++++++++---------
arch/x86/kernel/signal_compat.c | 34 +++++++++++++++++++++++++++++++---
kernel/signal.c | 7 +++++++
6 files changed, 60 insertions(+), 13 deletions(-)
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 2f29f4e407c3..cb13c0564ea7 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -378,7 +378,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
put_user_ex(*((u64 *)&code), (u64 __user *)frame->retcode);
} put_user_catch(err);
- err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
+ err |= __copy_siginfo_to_user32(&frame->info, &ksig->info, false);
err |= ia32_setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
diff --git a/arch/x86/include/asm/fpu/signal.h b/arch/x86/include/asm/fpu/signal.h
index 0e970d00dfcd..20a1fbf7fe4e 100644
--- a/arch/x86/include/asm/fpu/signal.h
+++ b/arch/x86/include/asm/fpu/signal.h
@@ -19,6 +19,12 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
# define ia32_setup_rt_frame __setup_rt_frame
#endif
+#ifdef CONFIG_COMPAT
+int __copy_siginfo_to_user32(compat_siginfo_t __user *to,
+ const siginfo_t *from, bool x32_ABI);
+#endif
+
+
extern void convert_from_fxsr(struct user_i387_ia32_struct *env,
struct task_struct *tsk);
extern void convert_to_fxsr(struct task_struct *tsk,
diff --git a/arch/x86/include/asm/signal.h b/arch/x86/include/asm/signal.h
index dd1e7d6387ab..8af22be0fe61 100644
--- a/arch/x86/include/asm/signal.h
+++ b/arch/x86/include/asm/signal.h
@@ -23,6 +23,10 @@ typedef struct {
unsigned long sig[_NSIG_WORDS];
} sigset_t;
+/* non-uapi in-kernel SA_FLAGS for those indicates ABI for a signal frame */
+#define SA_IA32_ABI 0x02000000u
+#define SA_X32_ABI 0x01000000u
+
#ifndef CONFIG_COMPAT
typedef sigset_t compat_sigset_t;
#endif
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 04cb3212db2d..b1a5d252d482 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -42,6 +42,7 @@
#include <asm/syscalls.h>
#include <asm/sigframe.h>
+#include <asm/signal.h>
#define COPY(x) do { \
get_user_ex(regs->x, &sc->x); \
@@ -547,7 +548,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
return -EFAULT;
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
- if (copy_siginfo_to_user32(&frame->info, &ksig->info))
+ if (__copy_siginfo_to_user32(&frame->info, &ksig->info, true))
return -EFAULT;
}
@@ -660,20 +661,21 @@ badframe:
return 0;
}
-static inline int is_ia32_compat_frame(void)
+static inline int is_ia32_compat_frame(struct ksignal *ksig)
{
return IS_ENABLED(CONFIG_IA32_EMULATION) &&
- test_thread_flag(TIF_IA32);
+ ksig->ka.sa.sa_flags & SA_IA32_ABI;
}
-static inline int is_ia32_frame(void)
+static inline int is_ia32_frame(struct ksignal *ksig)
{
- return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame();
+ return IS_ENABLED(CONFIG_X86_32) || is_ia32_compat_frame(ksig);
}
-static inline int is_x32_frame(void)
+static inline int is_x32_frame(struct ksignal *ksig)
{
- return IS_ENABLED(CONFIG_X86_X32_ABI) && test_thread_flag(TIF_X32);
+ return IS_ENABLED(CONFIG_X86_X32_ABI) &&
+ ksig->ka.sa.sa_flags & SA_X32_ABI;
}
static int
@@ -684,12 +686,12 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
compat_sigset_t *cset = (compat_sigset_t *) set;
/* Set up the stack frame */
- if (is_ia32_frame()) {
+ if (is_ia32_frame(ksig)) {
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
return ia32_setup_rt_frame(usig, ksig, cset, regs);
else
return ia32_setup_frame(usig, ksig, cset, regs);
- } else if (is_x32_frame()) {
+ } else if (is_x32_frame(ksig)) {
return x32_setup_rt_frame(ksig, cset, regs);
} else {
return __setup_rt_frame(ksig->sig, ksig, set, regs);
diff --git a/arch/x86/kernel/signal_compat.c b/arch/x86/kernel/signal_compat.c
index b44564bf86a8..40df33753bae 100644
--- a/arch/x86/kernel/signal_compat.c
+++ b/arch/x86/kernel/signal_compat.c
@@ -1,5 +1,6 @@
#include <linux/compat.h>
#include <linux/uaccess.h>
+#include <linux/ptrace.h>
/*
* The compat_siginfo_t structure and handing code is very easy
@@ -92,10 +93,31 @@ static inline void signal_compat_build_tests(void)
/* any new si_fields should be added here */
}
-int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
+void sigaction_compat_abi(struct k_sigaction *act, struct k_sigaction *oact)
+{
+ /* Don't leak in-kernel non-uapi flags to user-space */
+ if (oact)
+ oact->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
+
+ if (!act)
+ return;
+
+ /* Don't let flags to be set from userspace */
+ act->sa.sa_flags &= ~(SA_IA32_ABI | SA_X32_ABI);
+
+ if (user_64bit_mode(current_pt_regs()))
+ return;
+
+ if (in_ia32_syscall())
+ act->sa.sa_flags |= SA_IA32_ABI;
+ if (in_x32_syscall())
+ act->sa.sa_flags |= SA_X32_ABI;
+}
+
+int __copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from,
+ bool x32_ABI)
{
int err = 0;
- bool ia32 = test_thread_flag(TIF_IA32);
signal_compat_build_tests();
@@ -146,7 +168,7 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
put_user_ex(from->si_arch, &to->si_arch);
break;
case __SI_CHLD >> 16:
- if (ia32) {
+ if (!x32_ABI) {
put_user_ex(from->si_utime, &to->si_utime);
put_user_ex(from->si_stime, &to->si_stime);
} else {
@@ -180,6 +202,12 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
return err;
}
+/* from syscall's path, where we know the ABI */
+int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
+{
+ return __copy_siginfo_to_user32(to, from, in_x32_syscall());
+}
+
int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
{
int err = 0;
diff --git a/kernel/signal.c b/kernel/signal.c
index af21afc00d08..75761acc77cf 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3044,6 +3044,11 @@ void kernel_sigaction(int sig, __sighandler_t action)
}
EXPORT_SYMBOL(kernel_sigaction);
+void __weak sigaction_compat_abi(struct k_sigaction *act,
+ struct k_sigaction *oact)
+{
+}
+
int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
struct task_struct *p = current, *t;
@@ -3059,6 +3064,8 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
if (oact)
*oact = *k;
+ sigaction_compat_abi(act, oact);
+
if (act) {
sigdelsetmask(&act->sa.sa_mask,
sigmask(SIGKILL) | sigmask(SIGSTOP));
--
2.9.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64
2016-09-05 13:33 [PATCHv5 0/6] x86: 32-bit compatible C/R on x86_64 Dmitry Safonov
` (5 preceding siblings ...)
2016-09-05 13:33 ` [PATCHv5 6/6] x86/signal: add SA_{X32,IA32}_ABI sa_flags Dmitry Safonov
@ 2016-09-14 15:56 ` Dmitry Safonov
6 siblings, 0 replies; 9+ messages in thread
From: Dmitry Safonov @ 2016-09-14 15:56 UTC (permalink / raw)
To: linux-kernel, mingo; +Cc: 0x7f454c46, linux-mm, x86
On 09/05/2016 04:33 PM, Dmitry Safonov wrote:
> Changes from v4:
> - check both vm_ops and vm_private_data to avoid (unlikely) confusion
> with some other vma in map_vdso_once (as Andy noticed) - which would
> lead to unable to use this API in that unlikely-case
> (vm_private_data may be uninitialized and be the same as vvar_mapping
> or vdso_mapping pointer) - so I introduced one-liner helper
> vma_is_special_mapping().
>
> Changes from v3:
> - proper ifdefs around vdso_image_32
> - missed Reviewed-by tag
Ping?
It looks like, all acks are there and there are no objections.
--
Dmitry
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 9+ messages in thread