From patchwork Fri Jul 14 06:51:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Ellerman X-Patchwork-Id: 788150 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3x83Ns67b5z9ryk for ; Fri, 14 Jul 2017 16:55:41 +1000 (AEST) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3x83Ns5FcJzDqpK for ; Fri, 14 Jul 2017 16:55:41 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from ozlabs.org (bilbo.ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x83J13Qx5zDqlq for ; Fri, 14 Jul 2017 16:51:29 +1000 (AEST) Received: by ozlabs.org (Postfix) id 3x83J11sr4z9t1y; Fri, 14 Jul 2017 16:51:29 +1000 (AEST) Delivered-To: linuxppc-dev@ozlabs.org Received: by ozlabs.org (Postfix, from userid 1034) id 3x83J10CSdz9t2H; Fri, 14 Jul 2017 16:51:28 +1000 (AEST) From: Michael Ellerman To: linuxppc-dev@ozlabs.org Subject: [PATCH 3/3] powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y Date: Fri, 14 Jul 2017 16:51:23 +1000 Message-Id: <1500015083-23511-3-git-send-email-mpe@ellerman.id.au> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1500015083-23511-1-git-send-email-mpe@ellerman.id.au> References: <1500015083-23511-1-git-send-email-mpe@ellerman.id.au> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Currently even with STRICT_KERNEL_RWX we leave the __init text marked executable after init, which is bad. Add a hook to mark it NX (no-execute) before we free it, and implement it for radix and hash. Note that we use __init_end as the end address, not _einittext, because overlaps_kernel_text() uses __init_end, because there are additional executable sections other than .init.text between __init_begin and __init_end. Tested on radix and hash with: 0:mon> p $__init_begin *** 400 exception occurred Fixes: 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs") Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/book3s/64/hash.h | 1 + arch/powerpc/include/asm/book3s/64/pgtable.h | 7 +++++++ arch/powerpc/include/asm/book3s/64/radix.h | 1 + arch/powerpc/mm/mem.c | 1 + arch/powerpc/mm/pgtable-hash64.c | 12 ++++++++++++ arch/powerpc/mm/pgtable-radix.c | 8 ++++++++ arch/powerpc/mm/pgtable_64.c | 8 ++++++++ 7 files changed, 38 insertions(+) diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index 0ce513f2926f..36fc7bfe9e11 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -91,6 +91,7 @@ static inline int hash__pgd_bad(pgd_t pgd) } #ifdef CONFIG_STRICT_KERNEL_RWX extern void hash__mark_rodata_ro(void); +extern void hash__mark_initmem_nx(void); #endif extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr, diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index c0737c86a362..3d562b210c65 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1192,5 +1192,12 @@ static inline const int pud_pfn(pud_t pud) BUILD_BUG(); return 0; } + +#ifdef CONFIG_STRICT_KERNEL_RWX +void mark_initmem_nx(void); +#else +static inline void mark_initmem_nx(void) { } +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */ diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h index 487709ff6875..544440b5aff3 100644 --- a/arch/powerpc/include/asm/book3s/64/radix.h +++ b/arch/powerpc/include/asm/book3s/64/radix.h @@ -118,6 +118,7 @@ #ifdef CONFIG_STRICT_KERNEL_RWX extern void radix__mark_rodata_ro(void); +extern void radix__mark_initmem_nx(void); #endif static inline unsigned long __radix_pte_update(pte_t *ptep, unsigned long clr, diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 8541f18694a4..46b4e67d2372 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -402,6 +402,7 @@ void __init mem_init(void) void free_initmem(void) { ppc_md.progress = ppc_printk_progress; + mark_initmem_nx(); free_initmem_default(POISON_FREE_INITMEM); } diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c index 73019c52141f..443a2c66a304 100644 --- a/arch/powerpc/mm/pgtable-hash64.c +++ b/arch/powerpc/mm/pgtable-hash64.c @@ -460,4 +460,16 @@ void hash__mark_rodata_ro(void) WARN_ON(!hash__change_memory_range(start, end, PP_RXXX)); } + +void hash__mark_initmem_nx(void) +{ + unsigned long start, end, pp; + + start = (unsigned long)__init_begin; + end = (unsigned long)__init_end; + + pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL)); + + WARN_ON(!hash__change_memory_range(start, end, pp)); +} #endif diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c index 336e52ec652c..5cc50d47ce3f 100644 --- a/arch/powerpc/mm/pgtable-radix.c +++ b/arch/powerpc/mm/pgtable-radix.c @@ -162,6 +162,14 @@ void radix__mark_rodata_ro(void) radix__change_memory_range(start, end, _PAGE_WRITE); } + +void radix__mark_initmem_nx(void) +{ + unsigned long start = (unsigned long)__init_begin; + unsigned long end = (unsigned long)__init_end; + + radix__change_memory_range(start, end, _PAGE_EXEC); +} #endif /* CONFIG_STRICT_KERNEL_RWX */ static inline void __meminit print_mapping(unsigned long start, diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 5c0b795d656c..0736e94c7615 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -505,4 +505,12 @@ void mark_rodata_ro(void) else hash__mark_rodata_ro(); } + +void mark_initmem_nx(void) +{ + if (radix_enabled()) + radix__mark_initmem_nx(); + else + hash__mark_initmem_nx(); +} #endif