From: Dave Hansen <dave@sr71.net> To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, Dave Hansen <dave@sr71.net>, dave.hansen@linux.intel.com, arnd@arndb.de, mgorman@techsingularity.net, hughd@google.com, viro@zeniv.linux.org.uk Subject: [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Date: Thu, 07 Jul 2016 05:47:23 -0700 [thread overview] Message-ID: <20160707124723.90B7635A@viggo.jf.intel.com> (raw) In-Reply-To: <20160707124719.3F04C882@viggo.jf.intel.com> 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 this clearing today 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_PKEY_FLAGS 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. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: x86@kernel.org Cc: torvalds@linux-foundation.org Cc: akpm@linux-foundation.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: mgorman@techsingularity.net Cc: hughd@google.com Cc: viro@zeniv.linux.org.uk --- b/arch/x86/include/asm/pkeys.h | 2 ++ b/include/linux/pkeys.h | 1 + b/mm/mprotect.c | 11 ++++++++++- 3 files changed, 13 insertions(+), 1 deletion(-) diff -puN arch/x86/include/asm/pkeys.h~pkeys-112-mask-off-correct-vm_flags arch/x86/include/asm/pkeys.h --- a/arch/x86/include/asm/pkeys.h~pkeys-112-mask-off-correct-vm_flags 2016-07-07 05:47:00.500788624 -0700 +++ b/arch/x86/include/asm/pkeys.h 2016-07-07 05:47:00.507788941 -0700 @@ -38,4 +38,6 @@ static inline int arch_override_mprotect extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val); +#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-112-mask-off-correct-vm_flags include/linux/pkeys.h --- a/include/linux/pkeys.h~pkeys-112-mask-off-correct-vm_flags 2016-07-07 05:47:00.501788669 -0700 +++ b/include/linux/pkeys.h 2016-07-07 05:47:00.508788987 -0700 @@ -16,6 +16,7 @@ #define execute_only_pkey(mm) (0) #define arch_override_mprotect_pkey(vma, prot, pkey) (0) #define PKEY_DEDICATED_EXECUTE_ONLY 0 +#define ARCH_VM_PKEY_FLAGS 0 #endif /* ! CONFIG_ARCH_HAS_PKEYS */ /* diff -puN mm/mprotect.c~pkeys-112-mask-off-correct-vm_flags mm/mprotect.c --- a/mm/mprotect.c~pkeys-112-mask-off-correct-vm_flags 2016-07-07 05:47:00.503788760 -0700 +++ b/mm/mprotect.c 2016-07-07 05:47:00.509789032 -0700 @@ -411,6 +411,7 @@ static int do_mprotect_pkey(unsigned lon prev = vma; for (nstart = start ; ; ) { + unsigned long mask_off_old_flags; unsigned long newflags; int new_vma_pkey; @@ -420,9 +421,17 @@ static int do_mprotect_pkey(unsigned lon if (rier && (vma->vm_flags & VM_MAYEXEC)) prot |= PROT_EXEC; + /* + * Each mprotect() call explicitly passes r/w/x permissions. + * If a permission is not passed to mprotect(), it must be + * cleared from the VMA. + */ + mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC | + ARCH_VM_PKEY_FLAGS; + new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); newflags = calc_vm_prot_bits(prot, new_vma_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)) { _
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@sr71.net> To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, Dave Hansen <dave@sr71.net>, dave.hansen@linux.intel.com, arnd@arndb.de, mgorman@techsingularity.net, hughd@google.com, viro@zeniv.linux.org.uk Subject: [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Date: Thu, 07 Jul 2016 05:47:23 -0700 [thread overview] Message-ID: <20160707124723.90B7635A@viggo.jf.intel.com> (raw) In-Reply-To: <20160707124719.3F04C882@viggo.jf.intel.com> 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 this clearing today 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_PKEY_FLAGS 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. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-mm@kvack.org Cc: x86@kernel.org Cc: torvalds@linux-foundation.org Cc: akpm@linux-foundation.org Cc: Arnd Bergmann <arnd@arndb.de> Cc: mgorman@techsingularity.net Cc: hughd@google.com Cc: viro@zeniv.linux.org.uk --- b/arch/x86/include/asm/pkeys.h | 2 ++ b/include/linux/pkeys.h | 1 + b/mm/mprotect.c | 11 ++++++++++- 3 files changed, 13 insertions(+), 1 deletion(-) diff -puN arch/x86/include/asm/pkeys.h~pkeys-112-mask-off-correct-vm_flags arch/x86/include/asm/pkeys.h --- a/arch/x86/include/asm/pkeys.h~pkeys-112-mask-off-correct-vm_flags 2016-07-07 05:47:00.500788624 -0700 +++ b/arch/x86/include/asm/pkeys.h 2016-07-07 05:47:00.507788941 -0700 @@ -38,4 +38,6 @@ static inline int arch_override_mprotect extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val); +#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-112-mask-off-correct-vm_flags include/linux/pkeys.h --- a/include/linux/pkeys.h~pkeys-112-mask-off-correct-vm_flags 2016-07-07 05:47:00.501788669 -0700 +++ b/include/linux/pkeys.h 2016-07-07 05:47:00.508788987 -0700 @@ -16,6 +16,7 @@ #define execute_only_pkey(mm) (0) #define arch_override_mprotect_pkey(vma, prot, pkey) (0) #define PKEY_DEDICATED_EXECUTE_ONLY 0 +#define ARCH_VM_PKEY_FLAGS 0 #endif /* ! CONFIG_ARCH_HAS_PKEYS */ /* diff -puN mm/mprotect.c~pkeys-112-mask-off-correct-vm_flags mm/mprotect.c --- a/mm/mprotect.c~pkeys-112-mask-off-correct-vm_flags 2016-07-07 05:47:00.503788760 -0700 +++ b/mm/mprotect.c 2016-07-07 05:47:00.509789032 -0700 @@ -411,6 +411,7 @@ static int do_mprotect_pkey(unsigned lon prev = vma; for (nstart = start ; ; ) { + unsigned long mask_off_old_flags; unsigned long newflags; int new_vma_pkey; @@ -420,9 +421,17 @@ static int do_mprotect_pkey(unsigned lon if (rier && (vma->vm_flags & VM_MAYEXEC)) prot |= PROT_EXEC; + /* + * Each mprotect() call explicitly passes r/w/x permissions. + * If a permission is not passed to mprotect(), it must be + * cleared from the VMA. + */ + mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC | + ARCH_VM_PKEY_FLAGS; + new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey); newflags = calc_vm_prot_bits(prot, new_vma_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, 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>
next prev parent reply other threads:[~2016-07-07 12:48 UTC|newest] Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-07-07 12:47 [PATCH 0/9] [REVIEW-REQUEST] [v4] System Calls for Memory Protection Keys Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 12:47 ` [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 14:40 ` Mel Gorman 2016-07-07 14:40 ` Mel Gorman 2016-07-07 15:42 ` Dave Hansen 2016-07-07 15:42 ` Dave Hansen 2016-07-07 12:47 ` [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 14:40 ` Mel Gorman 2016-07-07 14:40 ` Mel Gorman 2016-07-07 16:51 ` Dave Hansen 2016-07-07 16:51 ` Dave Hansen 2016-07-08 10:15 ` Mel Gorman 2016-07-08 10:15 ` Mel Gorman 2016-07-07 12:47 ` Dave Hansen [this message] 2016-07-07 12:47 ` [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen 2016-07-07 12:47 ` [PATCH 4/9] x86: wire up mprotect_key() system call Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 12:47 ` [PATCH 5/9] x86, pkeys: allocation/free syscalls Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 14:40 ` Mel Gorman 2016-07-07 14:40 ` Mel Gorman 2016-07-07 15:38 ` Dave Hansen 2016-07-07 15:38 ` Dave Hansen 2016-07-07 12:47 ` [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 14:45 ` Mel Gorman 2016-07-07 14:45 ` Mel Gorman 2016-07-07 17:33 ` Dave Hansen 2016-07-07 17:33 ` Dave Hansen 2016-07-08 7:18 ` Ingo Molnar 2016-07-08 7:18 ` Ingo Molnar 2016-07-08 16:32 ` Dave Hansen 2016-07-08 16:32 ` Dave Hansen 2016-07-08 16:32 ` Dave Hansen 2016-07-09 8:37 ` Ingo Molnar 2016-07-09 8:37 ` Ingo Molnar 2016-07-09 8:37 ` Ingo Molnar 2016-07-11 4:25 ` Andy Lutomirski 2016-07-11 4:25 ` Andy Lutomirski 2016-07-11 7:35 ` Ingo Molnar 2016-07-11 7:35 ` Ingo Molnar 2016-07-11 7:35 ` Ingo Molnar 2016-07-11 14:28 ` Dave Hansen 2016-07-11 14:28 ` Dave Hansen 2016-07-12 7:13 ` Ingo Molnar 2016-07-12 7:13 ` Ingo Molnar 2016-07-12 15:39 ` Dave Hansen 2016-07-12 15:39 ` Dave Hansen 2016-07-11 14:50 ` Andy Lutomirski 2016-07-11 14:50 ` Andy Lutomirski 2016-07-11 14:34 ` Dave Hansen 2016-07-11 14:34 ` Dave Hansen 2016-07-11 14:34 ` Dave Hansen 2016-07-11 14:45 ` Andy Lutomirski 2016-07-11 14:45 ` Andy Lutomirski 2016-07-11 15:48 ` Dave Hansen 2016-07-11 15:48 ` Dave Hansen 2016-07-12 16:32 ` Andy Lutomirski 2016-07-12 16:32 ` Andy Lutomirski 2016-07-12 17:12 ` Dave Hansen 2016-07-12 17:12 ` Dave Hansen 2016-07-12 22:55 ` Andy Lutomirski 2016-07-12 22:55 ` Andy Lutomirski 2016-07-13 7:56 ` Ingo Molnar 2016-07-13 7:56 ` Ingo Molnar 2016-07-13 18:43 ` Andy Lutomirski 2016-07-13 18:43 ` Andy Lutomirski 2016-07-14 8:07 ` Ingo Molnar 2016-07-14 8:07 ` Ingo Molnar 2016-07-18 4:43 ` Andy Lutomirski 2016-07-18 4:43 ` Andy Lutomirski 2016-07-18 9:56 ` Ingo Molnar 2016-07-18 9:56 ` Ingo Molnar 2016-07-18 18:02 ` Dave Hansen 2016-07-18 18:02 ` Dave Hansen 2016-07-18 18:02 ` Dave Hansen 2016-07-18 20:12 ` Dave Hansen 2016-07-18 20:12 ` Dave Hansen 2016-07-18 20:12 ` Dave Hansen 2016-07-08 19:26 ` Dave Hansen 2016-07-08 19:26 ` Dave Hansen 2016-07-08 10:22 ` Mel Gorman 2016-07-08 10:22 ` Mel Gorman 2016-07-08 10:22 ` Mel Gorman 2016-07-07 12:47 ` [PATCH 7/9] generic syscalls: wire up memory protection keys syscalls Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 12:47 ` [PATCH 8/9] pkeys: add details of system call use to Documentation/ Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 12:47 ` [PATCH 9/9] x86, pkeys: add self-tests Dave Hansen 2016-07-07 12:47 ` Dave Hansen 2016-07-07 14:47 ` [PATCH 0/9] [REVIEW-REQUEST] [v4] System Calls for Memory Protection Keys Mel Gorman 2016-07-07 14:47 ` Mel Gorman 2016-07-07 14:47 ` Mel Gorman 2016-07-08 18:38 ` Hugh Dickins 2016-07-08 18:38 ` Hugh Dickins 2016-07-08 18:38 ` Hugh Dickins -- strict thread matches above, loose matches on Subject: below -- 2016-06-09 0:01 [PATCH 0/9] [v3] " Dave Hansen 2016-06-09 0:01 ` [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen 2016-06-09 0:01 ` Dave Hansen 2016-06-07 20:47 [PATCH 0/9] [v2] System Calls for Memory Protection Keys Dave Hansen 2016-06-07 20:47 ` [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen 2016-06-07 20:47 ` Dave Hansen
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