From: Ram Pai <linuxram@us.ibm.com>
To: mpe@ellerman.id.au
Cc: fweimer@redhat.com, Ulrich.Weigand@de.ibm.com,
dave.hansen@linux.intel.com, linuxram@us.ibm.com,
mhocko@kernel.org, bauerman@linux.vnet.ibm.com,
msuchanek@suse.de, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] powerpc/pkeys: copy pkey-tracking-information at fork()
Date: Mon, 3 Dec 2018 12:43:22 -0800 [thread overview]
Message-ID: <1543869802-15372-1-git-send-email-linuxram@us.ibm.com> (raw)
At fork(), the pkey tracking information is not copied over
to the mm_struct of the child. This can cause the child to erroneously
allocate keys that were already allocated. Any allocated execute-only
key is lost aswell.
Add code; called by dup_mmap(), to copy the pkey state from
parent to child explicitly.
This problem was originally found by Dave Hansen on x86, which turns
out to be a problem on powerpc aswell.
Testing:
Passes the new selftest added by Dave Hansen. I have temporarily
captured that selftest at
https://github.com/rampai/memorykeys/ -b memkey.v15-rc6
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
arch/powerpc/include/asm/mmu_context.h | 15 +++++++++------
arch/powerpc/mm/pkeys.c | 7 +++++++
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 0381394..cb16146 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -217,12 +217,6 @@ static inline void enter_lazy_tlb(struct mm_struct *mm,
#endif
}
-static inline int arch_dup_mmap(struct mm_struct *oldmm,
- struct mm_struct *mm)
-{
- return 0;
-}
-
#ifndef CONFIG_PPC_BOOK3S_64
static inline void arch_exit_mmap(struct mm_struct *mm)
{
@@ -247,6 +241,7 @@ static inline void arch_bprm_mm_init(struct mm_struct *mm,
#ifdef CONFIG_PPC_MEM_KEYS
bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
bool execute, bool foreign);
+void arch_dup_pkeys(struct mm_struct *oldmm, struct mm_struct *mm);
#else /* CONFIG_PPC_MEM_KEYS */
static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
bool write, bool execute, bool foreign)
@@ -259,6 +254,7 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
#define thread_pkey_regs_save(thread)
#define thread_pkey_regs_restore(new_thread, old_thread)
#define thread_pkey_regs_init(thread)
+#define arch_dup_pkeys(oldmm, mm)
static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
{
@@ -267,5 +263,12 @@ static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
#endif /* CONFIG_PPC_MEM_KEYS */
+static inline int arch_dup_mmap(struct mm_struct *oldmm,
+ struct mm_struct *mm)
+{
+ arch_dup_pkeys(oldmm, mm);
+ return 0;
+}
+
#endif /* __KERNEL__ */
#endif /* __ASM_POWERPC_MMU_CONTEXT_H */
diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c
index b271b28..5d65c47 100644
--- a/arch/powerpc/mm/pkeys.c
+++ b/arch/powerpc/mm/pkeys.c
@@ -414,3 +414,10 @@ bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
return pkey_access_permitted(vma_pkey(vma), write, execute);
}
+
+void arch_dup_pkeys(struct mm_struct *oldmm, struct mm_struct *mm)
+{
+ /* Duplicate the oldmm pkey state in mm: */
+ mm_pkey_allocation_map(mm) = mm_pkey_allocation_map(oldmm);
+ mm->context.execute_only_pkey = oldmm->context.execute_only_pkey;
+}
--
1.7.1
next reply other threads:[~2018-12-03 20:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 20:43 Ram Pai [this message]
2018-12-04 0:37 ` [PATCH] powerpc/pkeys: copy pkey-tracking-information at fork() Thiago Jung Bauermann
2018-12-04 13:00 ` Florian Weimer
2018-12-20 13:19 ` Michael Ellerman
2018-12-20 19:01 ` Ram Pai
2018-12-20 20:03 ` [PATCH v2] " Ram Pai
2018-12-21 0:55 ` Michael Ellerman
2018-12-23 13:28 ` [v2] " Michael Ellerman
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