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https://github.com/Divested-Mobile/DivestOS-Build.git
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151 lines
4.4 KiB
Diff
151 lines
4.4 KiB
Diff
From 4256415b296348ff16cd17a5b8f8dce4dea37328 Mon Sep 17 00:00:00 2001
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From: Larry Bassel <lbassel@codeaurora.org>
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Date: Mon, 29 Jul 2013 13:43:17 -0700
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Subject: msm: Make CONFIG_STRICT_MEMORY_RWX even stricter
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If CONFIG_STRICT_MEMORY_RWX was set, the first section (containing
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the kernel page table and the initial code) and the section
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containing the init code were both given RWX permission, which is
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a potential security hole.
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Pad the first section after the initial code (which will never
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be executed when the MMU is on) to make the rest of the kernel
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text start in the second section and make the first section RW.
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Move some data which had ended up in the "init text"
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section into the "init data" one, as this is RW, not RX.
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Make the "init text" RX.
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We will not free the section containing the "init text",
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because if we do, the kernel will allocate memory for RW data there.
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Change-Id: I6ca5f4e07342c374246f04a3fee18042fd47c33b
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CRs-fixed: 513919
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Signed-off-by: Larry Bassel <lbassel@codeaurora.org>
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---
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arch/arm/kernel/vmlinux.lds.S | 12 +++++++-----
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arch/arm/mm/init.c | 9 +++++++++
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arch/arm/mm/mmu.c | 15 +++++++--------
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3 files changed, 23 insertions(+), 13 deletions(-)
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diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
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index ae59e5a..0bf55ae 100644
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--- a/arch/arm/kernel/vmlinux.lds.S
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+++ b/arch/arm/kernel/vmlinux.lds.S
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@@ -93,6 +93,9 @@ SECTIONS
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_text = .;
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HEAD_TEXT
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}
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+#ifdef CONFIG_STRICT_MEMORY_RWX
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+ . = ALIGN(1<<SECTION_SHIFT);
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+#endif
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.text : { /* Real text segment */
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_stext = .; /* Text and read-only data */
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@@ -115,10 +118,10 @@ SECTIONS
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*(.got) /* Global offset table */
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ARM_CPU_KEEP(PROC_INFO)
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}
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+
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#ifdef CONFIG_STRICT_MEMORY_RWX
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. = ALIGN(1<<SECTION_SHIFT);
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#endif
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-
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RO_DATA(PAGE_SIZE)
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#ifdef CONFIG_ARM_UNWIND
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@@ -156,6 +159,9 @@ SECTIONS
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.init.proc.info : {
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ARM_CPU_DISCARD(PROC_INFO)
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}
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+#ifdef CONFIG_STRICT_MEMORY_RWX
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+ . = ALIGN(1<<SECTION_SHIFT);
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+#endif
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.init.arch.info : {
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__arch_info_begin = .;
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*(.arch.info.init)
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@@ -190,10 +196,6 @@ SECTIONS
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INIT_RAM_FS
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}
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#ifndef CONFIG_XIP_KERNEL
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-#ifdef CONFIG_STRICT_MEMORY_RWX
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- . = ALIGN(1<<SECTION_SHIFT);
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-#endif
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- __init_data = .;
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.exit.data : {
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ARM_EXIT_KEEP(EXIT_DATA)
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}
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diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
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index 34cb153..e82ea2b 100644
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--- a/arch/arm/mm/init.c
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+++ b/arch/arm/mm/init.c
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@@ -909,6 +909,14 @@ void free_initmem(void)
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"TCM link");
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#endif
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+#ifdef CONFIG_STRICT_MEMORY_RWX
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+ poison_init_mem((char *)__arch_info_begin,
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+ __init_end - (char *)__arch_info_begin);
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+ reclaimed_initmem = free_area(__phys_to_pfn(__pa(__arch_info_begin)),
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+ __phys_to_pfn(__pa(__init_end)),
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+ "init");
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+ totalram_pages += reclaimed_initmem;
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+#else
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poison_init_mem(__init_begin, __init_end - __init_begin);
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if (!machine_is_integrator() && !machine_is_cintegrator()) {
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reclaimed_initmem = free_area(__phys_to_pfn(__pa(__init_begin)),
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@@ -916,6 +924,7 @@ void free_initmem(void)
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"init");
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totalram_pages += reclaimed_initmem;
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}
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+#endif
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}
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#ifdef CONFIG_BLK_DEV_INITRD
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diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
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index c2efc34..e5a60a9 100644
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--- a/arch/arm/mm/mmu.c
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+++ b/arch/arm/mm/mmu.c
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@@ -1379,8 +1379,6 @@ void mem_text_write_kernel_word(unsigned long *addr, unsigned long word)
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}
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EXPORT_SYMBOL(mem_text_write_kernel_word);
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-extern char __init_data[];
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-
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static void __init map_lowmem(void)
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{
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struct memblock_region *reg;
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@@ -1401,7 +1399,7 @@ static void __init map_lowmem(void)
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#ifdef CONFIG_STRICT_MEMORY_RWX
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if (start <= __pa(_text) && __pa(_text) < end) {
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map.length = SECTION_SIZE;
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- map.type = MT_MEMORY;
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+ map.type = MT_MEMORY_RW;
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create_mapping(&map);
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@@ -1421,14 +1419,15 @@ static void __init map_lowmem(void)
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map.pfn = __phys_to_pfn(__pa(__init_begin));
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map.virtual = (unsigned long)__init_begin;
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- map.length = __init_data - __init_begin;
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- map.type = MT_MEMORY;
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+ map.length = (char *)__arch_info_begin - __init_begin;
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+ map.type = MT_MEMORY_RX;
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create_mapping(&map);
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- map.pfn = __phys_to_pfn(__pa(__init_data));
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- map.virtual = (unsigned long)__init_data;
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- map.length = __phys_to_virt(end) - (unsigned int)__init_data;
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+ map.pfn = __phys_to_pfn(__pa(__arch_info_begin));
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+ map.virtual = (unsigned long)__arch_info_begin;
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+ map.length = __phys_to_virt(end) -
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+ (unsigned long)__arch_info_begin;
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map.type = MT_MEMORY_RW;
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} else {
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map.length = end - start;
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--
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cgit v1.1
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