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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-06 19:07:33 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-06 19:07:33 (GMT) |
commit | 4f00b901d4233a78e6ca4d44c8c6fc5d38a3ee9e (patch) | |
tree | 9b9da4230d33c47298d4fa3e93a4a5f0cb047ee8 /arch/x86/mm | |
parent | b4c6e2ea5e46b03c764a918f4999a77a3149979f (diff) | |
parent | 94462ad3b14739d158a1ab87bb30008c1e5a6bc1 (diff) | |
download | linux-4f00b901d4233a78e6ca4d44c8c6fc5d38a3ee9e.tar.xz |
Merge branch 'x86-security-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-security-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
module: Move RO/NX module protection to after ftrace module update
x86: Resume trampoline must be executable
x86: Add RO/NX protection for loadable kernel modules
x86: Add NX protection for kernel data
x86: Fix improper large page preservation
Diffstat (limited to 'arch/x86/mm')
-rw-r--r-- | arch/x86/mm/init.c | 3 | ||||
-rw-r--r-- | arch/x86/mm/init_32.c | 20 | ||||
-rw-r--r-- | arch/x86/mm/pageattr.c | 33 |
3 files changed, 43 insertions, 13 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index c0e28a1..947f42ab 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -364,8 +364,9 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) /* * We just marked the kernel text read only above, now that * we are going to free part of that, we need to make that - * writeable first. + * writeable and non-executable first. */ + set_memory_nx(begin, (end - begin) >> PAGE_SHIFT); set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10); diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 0e969f9..f89b5bb 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -226,7 +226,7 @@ page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) static inline int is_kernel_text(unsigned long addr) { - if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end) + if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) return 1; return 0; } @@ -912,6 +912,23 @@ void set_kernel_text_ro(void) set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); } +static void mark_nxdata_nx(void) +{ + /* + * When this called, init has already been executed and released, + * so everything past _etext sould be NX. + */ + unsigned long start = PFN_ALIGN(_etext); + /* + * This comes from is_kernel_text upper limit. Also HPAGE where used: + */ + unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; + + if (__supported_pte_mask & _PAGE_NX) + printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); + set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); +} + void mark_rodata_ro(void) { unsigned long start = PFN_ALIGN(_text); @@ -946,6 +963,7 @@ void mark_rodata_ro(void) printk(KERN_INFO "Testing CPA: write protecting again\n"); set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); #endif + mark_nxdata_nx(); } #endif diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 532e793..8b830ca 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -13,6 +13,7 @@ #include <linux/pfn.h> #include <linux/percpu.h> #include <linux/gfp.h> +#include <linux/pci.h> #include <asm/e820.h> #include <asm/processor.h> @@ -255,13 +256,16 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, unsigned long pfn) { pgprot_t forbidden = __pgprot(0); + pgprot_t required = __pgprot(0); /* * The BIOS area between 640k and 1Mb needs to be executable for * PCI BIOS based config access (CONFIG_PCI_GOBIOS) support. */ - if (within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT)) +#ifdef CONFIG_PCI_BIOS + if (pcibios_enabled && within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_NX; +#endif /* * The kernel text needs to be executable for obvious reasons @@ -278,6 +282,12 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT, __pa((unsigned long)__end_rodata) >> PAGE_SHIFT)) pgprot_val(forbidden) |= _PAGE_RW; + /* + * .data and .bss should always be writable. + */ + if (within(address, (unsigned long)_sdata, (unsigned long)_edata) || + within(address, (unsigned long)__bss_start, (unsigned long)__bss_stop)) + pgprot_val(required) |= _PAGE_RW; #if defined(CONFIG_X86_64) && defined(CONFIG_DEBUG_RODATA) /* @@ -317,6 +327,7 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long address, #endif prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden)); + prot = __pgprot(pgprot_val(prot) | pgprot_val(required)); return prot; } @@ -393,7 +404,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, { unsigned long nextpage_addr, numpages, pmask, psize, flags, addr, pfn; pte_t new_pte, old_pte, *tmp; - pgprot_t old_prot, new_prot; + pgprot_t old_prot, new_prot, req_prot; int i, do_split = 1; unsigned int level; @@ -438,10 +449,10 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * We are safe now. Check whether the new pgprot is the same: */ old_pte = *kpte; - old_prot = new_prot = pte_pgprot(old_pte); + old_prot = new_prot = req_prot = pte_pgprot(old_pte); - pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr); - pgprot_val(new_prot) |= pgprot_val(cpa->mask_set); + pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr); + pgprot_val(req_prot) |= pgprot_val(cpa->mask_set); /* * old_pte points to the large page base address. So we need @@ -450,17 +461,17 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, pfn = pte_pfn(old_pte) + ((address & (psize - 1)) >> PAGE_SHIFT); cpa->pfn = pfn; - new_prot = static_protections(new_prot, address, pfn); + new_prot = static_protections(req_prot, address, pfn); /* * We need to check the full range, whether * static_protection() requires a different pgprot for one of * the pages in the range we try to preserve: */ - addr = address + PAGE_SIZE; - pfn++; - for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE, pfn++) { - pgprot_t chk_prot = static_protections(new_prot, addr, pfn); + addr = address & pmask; + pfn = pte_pfn(old_pte); + for (i = 0; i < (psize >> PAGE_SHIFT); i++, addr += PAGE_SIZE, pfn++) { + pgprot_t chk_prot = static_protections(req_prot, addr, pfn); if (pgprot_val(chk_prot) != pgprot_val(new_prot)) goto out_unlock; @@ -483,7 +494,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * that we limited the number of possible pages already to * the number of pages in the large page. */ - if (address == (nextpage_addr - psize) && cpa->numpages == numpages) { + if (address == (address & pmask) && cpa->numpages == (psize >> PAGE_SHIFT)) { /* * The address is aligned and the number of pages * covers the full page. |