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-rw-r--r--arch/x86/include/asm/pgtable_types.h2
-rw-r--r--arch/x86/mm/fault.c7
-rw-r--r--arch/x86/mm/pat/set_memory.c68
3 files changed, 60 insertions, 17 deletions
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 9abb8cc4cd47..b78644962626 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -567,6 +567,8 @@ static inline void update_page_count(int level, unsigned long pages) { }
extern pte_t *lookup_address(unsigned long address, unsigned int *level);
extern pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
unsigned int *level);
+pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,
+ unsigned int *level, bool *nx, bool *rw);
extern pmd_t *lookup_pmd_address(unsigned long address);
extern phys_addr_t slow_virt_to_phys(void *__address);
extern int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn,
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index bba4e020dd64..f26ecabc9424 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -514,18 +514,19 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad
if (error_code & X86_PF_INSTR) {
unsigned int level;
+ bool nx, rw;
pgd_t *pgd;
pte_t *pte;
pgd = __va(read_cr3_pa());
pgd += pgd_index(address);
- pte = lookup_address_in_pgd(pgd, address, &level);
+ pte = lookup_address_in_pgd_attr(pgd, address, &level, &nx, &rw);
- if (pte && pte_present(*pte) && !pte_exec(*pte))
+ if (pte && pte_present(*pte) && (!pte_exec(*pte) || nx))
pr_crit("kernel tried to execute NX-protected page - exploit attempt? (uid: %d)\n",
from_kuid(&init_user_ns, current_uid()));
- if (pte && pte_present(*pte) && pte_exec(*pte) &&
+ if (pte && pte_present(*pte) && pte_exec(*pte) && !nx &&
(pgd_flags(*pgd) & _PAGE_USER) &&
(__read_cr4() & X86_CR4_SMEP))
pr_crit("unable to execute userspace code (SMEP?) (uid: %d)\n",
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 80c9037ffadf..19fdfbb171ed 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -619,7 +619,8 @@ static inline pgprot_t static_protections(pgprot_t prot, unsigned long start,
* Validate strict W^X semantics.
*/
static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long start,
- unsigned long pfn, unsigned long npg)
+ unsigned long pfn, unsigned long npg,
+ bool nx, bool rw)
{
unsigned long end;
@@ -641,6 +642,10 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star
if ((pgprot_val(new) & (_PAGE_RW | _PAGE_NX)) != _PAGE_RW)
return new;
+ /* Non-leaf translation entries can disable writing or execution. */
+ if (!rw || nx)
+ return new;
+
end = start + npg * PAGE_SIZE - 1;
WARN_ONCE(1, "CPA detected W^X violation: %016llx -> %016llx range: 0x%016lx - 0x%016lx PFN %lx\n",
(unsigned long long)pgprot_val(old),
@@ -657,20 +662,26 @@ static inline pgprot_t verify_rwx(pgprot_t old, pgprot_t new, unsigned long star
/*
* Lookup the page table entry for a virtual address in a specific pgd.
- * Return a pointer to the entry and the level of the mapping.
+ * Return a pointer to the entry, the level of the mapping, and the effective
+ * NX and RW bits of all page table levels.
*/
-pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
- unsigned int *level)
+pte_t *lookup_address_in_pgd_attr(pgd_t *pgd, unsigned long address,
+ unsigned int *level, bool *nx, bool *rw)
{
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
*level = PG_LEVEL_NONE;
+ *nx = false;
+ *rw = true;
if (pgd_none(*pgd))
return NULL;
+ *nx |= pgd_flags(*pgd) & _PAGE_NX;
+ *rw &= pgd_flags(*pgd) & _PAGE_RW;
+
p4d = p4d_offset(pgd, address);
if (p4d_none(*p4d))
return NULL;
@@ -679,6 +690,9 @@ pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
if (p4d_leaf(*p4d) || !p4d_present(*p4d))
return (pte_t *)p4d;
+ *nx |= p4d_flags(*p4d) & _PAGE_NX;
+ *rw &= p4d_flags(*p4d) & _PAGE_RW;
+
pud = pud_offset(p4d, address);
if (pud_none(*pud))
return NULL;
@@ -687,6 +701,9 @@ pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
if (pud_leaf(*pud) || !pud_present(*pud))
return (pte_t *)pud;
+ *nx |= pud_flags(*pud) & _PAGE_NX;
+ *rw &= pud_flags(*pud) & _PAGE_RW;
+
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
return NULL;
@@ -695,12 +712,27 @@ pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
if (pmd_leaf(*pmd) || !pmd_present(*pmd))
return (pte_t *)pmd;
+ *nx |= pmd_flags(*pmd) & _PAGE_NX;
+ *rw &= pmd_flags(*pmd) & _PAGE_RW;
+
*level = PG_LEVEL_4K;
return pte_offset_kernel(pmd, address);
}
/*
+ * Lookup the page table entry for a virtual address in a specific pgd.
+ * Return a pointer to the entry and the level of the mapping.
+ */
+pte_t *lookup_address_in_pgd(pgd_t *pgd, unsigned long address,
+ unsigned int *level)
+{
+ bool nx, rw;
+
+ return lookup_address_in_pgd_attr(pgd, address, level, &nx, &rw);
+}
+
+/*
* Lookup the page table entry for a virtual address. Return a pointer
* to the entry and the level of the mapping.
*
@@ -715,13 +747,16 @@ pte_t *lookup_address(unsigned long address, unsigned int *level)
EXPORT_SYMBOL_GPL(lookup_address);
static pte_t *_lookup_address_cpa(struct cpa_data *cpa, unsigned long address,
- unsigned int *level)
+ unsigned int *level, bool *nx, bool *rw)
{
- if (cpa->pgd)
- return lookup_address_in_pgd(cpa->pgd + pgd_index(address),
- address, level);
+ pgd_t *pgd;
+
+ if (!cpa->pgd)
+ pgd = pgd_offset_k(address);
+ else
+ pgd = cpa->pgd + pgd_index(address);
- return lookup_address(address, level);
+ return lookup_address_in_pgd_attr(pgd, address, level, nx, rw);
}
/*
@@ -849,12 +884,13 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
pgprot_t old_prot, new_prot, req_prot, chk_prot;
pte_t new_pte, *tmp;
enum pg_level level;
+ bool nx, rw;
/*
* Check for races, another CPU might have split this page
* up already:
*/
- tmp = _lookup_address_cpa(cpa, address, &level);
+ tmp = _lookup_address_cpa(cpa, address, &level, &nx, &rw);
if (tmp != kpte)
return 1;
@@ -965,7 +1001,8 @@ static int __should_split_large_page(pte_t *kpte, unsigned long address,
new_prot = static_protections(req_prot, lpaddr, old_pfn, numpages,
psize, CPA_DETECT);
- new_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages);
+ new_prot = verify_rwx(old_prot, new_prot, lpaddr, old_pfn, numpages,
+ nx, rw);
/*
* If there is a conflict, split the large page.
@@ -1046,6 +1083,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
pte_t *pbase = (pte_t *)page_address(base);
unsigned int i, level;
pgprot_t ref_prot;
+ bool nx, rw;
pte_t *tmp;
spin_lock(&pgd_lock);
@@ -1053,7 +1091,7 @@ __split_large_page(struct cpa_data *cpa, pte_t *kpte, unsigned long address,
* Check for races, another CPU might have split this page
* up for us already:
*/
- tmp = _lookup_address_cpa(cpa, address, &level);
+ tmp = _lookup_address_cpa(cpa, address, &level, &nx, &rw);
if (tmp != kpte) {
spin_unlock(&pgd_lock);
return 1;
@@ -1594,10 +1632,11 @@ static int __change_page_attr(struct cpa_data *cpa, int primary)
int do_split, err;
unsigned int level;
pte_t *kpte, old_pte;
+ bool nx, rw;
address = __cpa_addr(cpa, cpa->curpage);
repeat:
- kpte = _lookup_address_cpa(cpa, address, &level);
+ kpte = _lookup_address_cpa(cpa, address, &level, &nx, &rw);
if (!kpte)
return __cpa_process_fault(cpa, address, primary);
@@ -1619,7 +1658,8 @@ repeat:
new_prot = static_protections(new_prot, address, pfn, 1, 0,
CPA_PROTECT);
- new_prot = verify_rwx(old_prot, new_prot, address, pfn, 1);
+ new_prot = verify_rwx(old_prot, new_prot, address, pfn, 1,
+ nx, rw);
new_prot = pgprot_clear_protnone_bits(new_prot);
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-11 23:29:04 +0000