From: Jeff Xu jeffxu@google.com
check seal for munmap(2).
Signed-off-by: Jeff Xu jeffxu@google.com --- include/linux/mm.h | 2 +- mm/mmap.c | 22 ++++++++++++++-------- mm/mremap.c | 5 +++-- 3 files changed, 18 insertions(+), 11 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h index aafdb68950f8..95b793eb3a80 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3294,7 +3294,7 @@ extern unsigned long do_mmap(struct file *file, unsigned long addr, unsigned long pgoff, unsigned long *populate, struct list_head *uf); extern int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, - bool unlock); + bool unlock, enum caller_origin called); extern int do_munmap(struct mm_struct *, unsigned long, size_t, struct list_head *uf); extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior); diff --git a/mm/mmap.c b/mm/mmap.c index 9b6c477e713e..f4bfcc5d2c10 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2601,6 +2601,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, * @len: The length of the range to munmap * @uf: The userfaultfd list_head * @unlock: set to true if the user wants to drop the mmap_lock on success + * @called: caller origin * * This function takes a @mas that is either pointing to the previous VMA or set * to MA_START and sets it up to remove the mapping(s). The @len will be @@ -2611,7 +2612,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, */ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, - bool unlock) + bool unlock, enum caller_origin called) { unsigned long end; struct vm_area_struct *vma; @@ -2623,6 +2624,9 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, if (end == start) return -EINVAL;
+ if (!can_modify_mm(mm, start, end, MM_ACTION_MUNMAP, called)) + return -EACCES; + /* arch_unmap() might do unmaps itself. */ arch_unmap(mm, start, end);
@@ -2650,7 +2654,8 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, { VMA_ITERATOR(vmi, mm, start);
- return do_vmi_munmap(&vmi, mm, start, len, uf, false); + return do_vmi_munmap(&vmi, mm, start, len, uf, false, + ON_BEHALF_OF_KERNEL); }
unsigned long mmap_region(struct file *file, unsigned long addr, @@ -2684,7 +2689,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, }
/* Unmap any existing mapping in the area */ - if (do_vmi_munmap(&vmi, mm, addr, len, uf, false)) + if (do_vmi_munmap(&vmi, mm, addr, len, uf, false, ON_BEHALF_OF_KERNEL)) return -ENOMEM;
/* @@ -2909,7 +2914,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, return error; }
-static int __vm_munmap(unsigned long start, size_t len, bool unlock) +static int __vm_munmap(unsigned long start, size_t len, bool unlock, + enum caller_origin called) { int ret; struct mm_struct *mm = current->mm; @@ -2919,7 +2925,7 @@ static int __vm_munmap(unsigned long start, size_t len, bool unlock) if (mmap_write_lock_killable(mm)) return -EINTR;
- ret = do_vmi_munmap(&vmi, mm, start, len, &uf, unlock); + ret = do_vmi_munmap(&vmi, mm, start, len, &uf, unlock, called); if (ret || !unlock) mmap_write_unlock(mm);
@@ -2929,14 +2935,14 @@ static int __vm_munmap(unsigned long start, size_t len, bool unlock)
int vm_munmap(unsigned long start, size_t len) { - return __vm_munmap(start, len, false); + return __vm_munmap(start, len, false, ON_BEHALF_OF_KERNEL); } EXPORT_SYMBOL(vm_munmap);
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) { addr = untagged_addr(addr); - return __vm_munmap(addr, len, true); + return __vm_munmap(addr, len, true, ON_BEHALF_OF_USERSPACE); }
@@ -3168,7 +3174,7 @@ int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) if (ret) goto limits_failed;
- ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0); + ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0, ON_BEHALF_OF_KERNEL); if (ret) goto munmap_failed;
diff --git a/mm/mremap.c b/mm/mremap.c index 056478c106ee..e43f9ceaa29d 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -715,7 +715,8 @@ static unsigned long move_vma(struct vm_area_struct *vma, }
vma_iter_init(&vmi, mm, old_addr); - if (!do_vmi_munmap(&vmi, mm, old_addr, old_len, uf_unmap, false)) { + if (!do_vmi_munmap(&vmi, mm, old_addr, old_len, uf_unmap, false, + ON_BEHALF_OF_KERNEL)) { /* OOM: unable to split vma, just get accounts right */ if (vm_flags & VM_ACCOUNT && !(flags & MREMAP_DONTUNMAP)) vm_acct_memory(old_len >> PAGE_SHIFT); @@ -1009,7 +1010,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, }
ret = do_vmi_munmap(&vmi, mm, addr + new_len, old_len - new_len, - &uf_unmap, true); + &uf_unmap, true, ON_BEHALF_OF_KERNEL); if (ret) goto out;