diff options
| -rw-r--r-- | drivers/lguest/page_tables.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index 7584662..f074f34 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -259,26 +259,35 @@ static void release_pte(pte_t pte) } /*:*/ -static void check_gpte(struct lg_cpu *cpu, pte_t gpte) +static bool check_gpte(struct lg_cpu *cpu, pte_t gpte) { if ((pte_flags(gpte) & _PAGE_PSE) || - pte_pfn(gpte) >= cpu->lg->pfn_limit) + pte_pfn(gpte) >= cpu->lg->pfn_limit) { kill_guest(cpu, "bad page table entry"); + return false; + } + return true; } -static void check_gpgd(struct lg_cpu *cpu, pgd_t gpgd) +static bool check_gpgd(struct lg_cpu *cpu, pgd_t gpgd) { if ((pgd_flags(gpgd) & ~CHECK_GPGD_MASK) || - (pgd_pfn(gpgd) >= cpu->lg->pfn_limit)) + (pgd_pfn(gpgd) >= cpu->lg->pfn_limit)) { kill_guest(cpu, "bad page directory entry"); + return false; + } + return true; } #ifdef CONFIG_X86_PAE -static void check_gpmd(struct lg_cpu *cpu, pmd_t gpmd) +static bool check_gpmd(struct lg_cpu *cpu, pmd_t gpmd) { if ((pmd_flags(gpmd) & ~_PAGE_TABLE) || - (pmd_pfn(gpmd) >= cpu->lg->pfn_limit)) + (pmd_pfn(gpmd) >= cpu->lg->pfn_limit)) { kill_guest(cpu, "bad page middle directory entry"); + return false; + } + return true; } #endif @@ -336,7 +345,8 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) return false; } /* We check that the Guest pgd is OK. */ - check_gpgd(cpu, gpgd); + if (!check_gpgd(cpu, gpgd)) + return false; /* * And we copy the flags to the shadow PGD entry. The page * number in the shadow PGD is the page we just allocated. @@ -372,7 +382,8 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) } /* We check that the Guest pmd is OK. */ - check_gpmd(cpu, gpmd); + if (!check_gpmd(cpu, gpmd)) + return false; /* * And we copy the flags to the shadow PMD entry. The page @@ -421,7 +432,8 @@ bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) * Check that the Guest PTE flags are OK, and the page number is below * the pfn_limit (ie. not mapping the Launcher binary). */ - check_gpte(cpu, gpte); + if (!check_gpte(cpu, gpte)) + return false; /* Add the _PAGE_ACCESSED and (for a write) _PAGE_DIRTY flag */ gpte = pte_mkyoung(gpte); @@ -857,7 +869,8 @@ static void do_set_pte(struct lg_cpu *cpu, int idx, * micro-benchmark. */ if (pte_flags(gpte) & (_PAGE_DIRTY | _PAGE_ACCESSED)) { - check_gpte(cpu, gpte); + if (!check_gpte(cpu, gpte)) + return; set_pte(spte, gpte_to_spte(cpu, gpte, pte_flags(gpte) & _PAGE_DIRTY)); |
