Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1283509
| From | Dave Hansen <dave@sr71.net> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional vm_flags |
| Date | 2015-12-04 02:20 +0100 |
| Message-ID | <qBNcu-4nR-39@gated-at.bofh.it> (permalink) |
| References | <qBNct-4nR-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Dave Hansen <dave.hansen@linux.intel.com>
Today, mprotect() takes 4 bits of data: PROT_READ/WRITE/EXEC/NONE.
Three of those bits: READ/WRITE/EXEC get translated directly in to
vma->vm_flags by calc_vm_prot_bits(). If a bit is unset in
mprotect()'s 'prot' argument then it must be cleared in vma->vm_flags
during the mprotect() call.
We do the by first calculating the VMA flags we want set, then
clearing the ones we do not want to inherit from the original VMA:
vm_flags = calc_vm_prot_bits(prot, key);
...
newflags = vm_flags;
newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
However, we *also* want to mask off the original VMA's vm_flags in
which we store the protection key.
To do that, this patch adds a new macro:
ARCH_VM_FLAGS_AFFECTED_BY_MPROTECT
which allows the architecture to specify additional bits that it would
like cleared. We use that to ensure that the VM_PKEY_BIT* bits get
cleared.
This got missed in my testing because I was always going from a pkey=0
VMA to a nonzero one. The current code works when we only set bits
but never clear them. I've fixed this up in my testing.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
---
b/arch/x86/include/asm/pkeys.h | 2 ++
b/include/linux/pkeys.h | 1 +
b/mm/mprotect.c | 9 ++++++++-
3 files changed, 11 insertions(+), 1 deletion(-)
diff -puN arch/x86/include/asm/pkeys.h~pkeys-mask-off-correct-vm_flags arch/x86/include/asm/pkeys.h
--- a/arch/x86/include/asm/pkeys.h~pkeys-mask-off-correct-vm_flags 2015-12-03 16:21:30.666899890 -0800
+++ b/arch/x86/include/asm/pkeys.h 2015-12-03 16:21:30.672900162 -0800
@@ -5,6 +5,8 @@
CONFIG_NR_PROTECTION_KEYS : 1)
#define arch_validate_pkey(pkey) (((pkey) >= 0) && ((pkey) < arch_max_pkey()))
+#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | VM_PKEY_BIT3)
+
#endif /*_ASM_X86_PKEYS_H */
diff -puN include/linux/pkeys.h~pkeys-mask-off-correct-vm_flags include/linux/pkeys.h
--- a/include/linux/pkeys.h~pkeys-mask-off-correct-vm_flags 2015-12-03 16:21:30.667899935 -0800
+++ b/include/linux/pkeys.h 2015-12-03 16:21:30.672900162 -0800
@@ -7,6 +7,7 @@
#include <asm/pkeys.h>
#include <asm/mmu_context.h>
#else /* ! CONFIG_ARCH_HAS_PKEYS */
+#define ARCH_VM_PKEY_FLAGS 0
/*
* This is called from mprotect_pkey().
diff -puN mm/mprotect.c~pkeys-mask-off-correct-vm_flags mm/mprotect.c
--- a/mm/mprotect.c~pkeys-mask-off-correct-vm_flags 2015-12-03 16:21:30.669900026 -0800
+++ b/mm/mprotect.c 2015-12-03 16:21:30.673900208 -0800
@@ -406,6 +406,13 @@ static int do_mprotect_pkey(unsigned lon
for (nstart = start ; ; ) {
unsigned long newflags;
+ /*
+ * Each mprotect() call explicitly passes r/w/x permissions.
+ * If a permission is not passed to mprotect(), it must be
+ * cleared from the VMA.
+ */
+ unsigned long mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC;
+ mask_off_old_flags |= ARCH_VM_PKEY_FLAGS;
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
@@ -417,7 +424,7 @@ static int do_mprotect_pkey(unsigned lon
newflags = calc_vm_prot_bits(prot, vma_pkey(vma));
else
newflags = calc_vm_prot_bits(prot, pkey);
- newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
+ newflags |= (vma->vm_flags & ~mask_off_old_flags);
/* newflags >> 4 shift VM_MAY% in place of VM_% */
if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
_
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 09/34] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 09/34] x86, pkeys: store protection in high VMA flags Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 15:20 +0100
[PATCH 32/34] x86, pkeys: add pkey set/get syscalls Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 29/34] x86: separate out LDT init from context init Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 31/34] x86, pkeys: allocation/free syscalls Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 12/34] signals, pkeys: notify userspace about protection key faults Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 20/34] x86, pkeys: differentiate instruction fetches Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 20/34] x86, pkeys: differentiate instruction fetches Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
[PATCH 19/34] x86, pkeys: optimize fault handling in access_error() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 19/34] x86, pkeys: optimize fault handling in access_error() Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
[PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 27/34] x86, pkeys: make mprotect_key() mask off additional vm_flags Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:50 +0100
[PATCH 23/34] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 23/34] x86, pkeys: add Kconfig prompt to existing config option Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:30 +0100
[PATCH 25/34] x86, pkeys: add arch_validate_pkey() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 25/34] x86, pkeys: add arch_validate_pkey() Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:50 +0100
[PATCH 33/34] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-05 08:00 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-07 17:50 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-09 12:10 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-09 16:50 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-09 17:50 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call Dave Hansen <dave@sr71.net> - 2015-12-09 18:10 +0100
Re: [PATCH 26/34] mm: implement new mprotect_key() system call "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-11 21:20 +0100
[PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 22/34] x86, pkeys: dump PTE pkey in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2015-12-04 02:20 +0100
[PATCH 14/34] x86, pkeys: add functions to fetch PKRU Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
Re: [PATCH 14/34] x86, pkeys: add functions to fetch PKRU Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 16:20 +0100
[PATCH 11/34] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 02/34] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
Re: [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:10 +0100
Re: [PATCH 16/34] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2015-12-08 19:40 +0100
[PATCH 10/34] x86, pkeys: arch-specific protection bits Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 16:20 +0100
Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Dave Hansen <dave@sr71.net> - 2015-12-08 17:40 +0100
Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 18:30 +0100
Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Dave Hansen <dave@sr71.net> - 2015-12-08 19:10 +0100
Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:40 +0100
Re: [PATCH 10/34] x86, pkeys: arch-specific protection bitsy Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:40 +0100
[PATCH 06/34] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 05/34] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 01/34] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 17/34] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
Re: [PATCH 17/34] x86, pkeys: check VMAs and PTEs for protection keys Thomas Gleixner <tglx@linutronix.de> - 2015-12-08 19:20 +0100
[PATCH 13/34] x86, pkeys: fill in pkey field in siginfo Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 08/34] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 07/34] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
[PATCH 04/34] x86, pkeys: cpuid bit definition Dave Hansen <dave@sr71.net> - 2015-12-04 02:30 +0100
Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen <dave@sr71.net> - 2015-12-05 00:40 +0100
Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski <luto@amacapital.net> - 2015-12-11 21:20 +0100
Re: [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski <luto@amacapital.net> - 2015-12-05 00:40 +0100
csiph-web