diff options
| -rw-r--r-- | fs/proc/task_mmu.c | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 98ba9ea96b19..bc651644b1b2 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -939,6 +939,7 @@ typedef struct { struct pagemapread { int pos, len; /* units: PM_ENTRY_BYTES, not bytes */ pagemap_entry_t *buffer; + bool show_pfn; }; #define PAGEMAP_WALK_SIZE (PMD_SIZE) @@ -1015,7 +1016,8 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm, struct page *page = NULL; if (pte_present(pte)) { - frame = pte_pfn(pte); + if (pm->show_pfn) + frame = pte_pfn(pte); flags |= PM_PRESENT; page = vm_normal_page(vma, addr, pte); if (pte_soft_dirty(pte)) @@ -1065,8 +1067,9 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, */ if (pmd_present(pmd)) { flags |= PM_PRESENT; - frame = pmd_pfn(pmd) + - ((addr & ~PMD_MASK) >> PAGE_SHIFT); + if (pm->show_pfn) + frame = pmd_pfn(pmd) + + ((addr & ~PMD_MASK) >> PAGE_SHIFT); } for (; addr != end; addr += PAGE_SIZE) { @@ -1075,7 +1078,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, err = add_to_pagemap(addr, &pme, pm); if (err) break; - if (flags & PM_PRESENT) + if (pm->show_pfn && (flags & PM_PRESENT)) frame++; } spin_unlock(ptl); @@ -1129,8 +1132,9 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask, flags |= PM_FILE; flags |= PM_PRESENT; - frame = pte_pfn(pte) + - ((addr & ~hmask) >> PAGE_SHIFT); + if (pm->show_pfn) + frame = pte_pfn(pte) + + ((addr & ~hmask) >> PAGE_SHIFT); } for (; addr != end; addr += PAGE_SIZE) { @@ -1139,7 +1143,7 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask, err = add_to_pagemap(addr, &pme, pm); if (err) return err; - if (flags & PM_PRESENT) + if (pm->show_pfn && (flags & PM_PRESENT)) frame++; } @@ -1198,6 +1202,9 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, if (!count) goto out_mm; + /* do not disclose physical addresses: attack vector */ + pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN); + pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT); pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY); ret = -ENOMEM; @@ -1267,10 +1274,6 @@ static int pagemap_open(struct inode *inode, struct file *file) { struct mm_struct *mm; - /* do not disclose physical addresses: attack vector */ - if (!capable(CAP_SYS_ADMIN)) - return -EPERM; - mm = proc_mem_open(inode, PTRACE_MODE_READ); if (IS_ERR(mm)) return PTR_ERR(mm); |