[PATCH] error path in setup_arg_pages() misses vm_unacct_memory()
Pavel Emelianov and Kirill Korotaev observe that fs and arch users of
security_vm_enough_memory tend to forget to vm_unacct_memory when a
failure occurs further down (typically in setup_arg_pages variants).
These are all users of insert_vm_struct, and that reservation will only
be unaccounted on exit if the vma is marked VM_ACCOUNT: which in some
cases it is (hidden inside VM_STACK_FLAGS) and in some cases it isn't.
So x86_64 32-bit and ppc64 vDSO ELFs have been leaking memory into
Committed_AS each time they're run. But don't add VM_ACCOUNT to them,
it's inappropriate to reserve against the very unlikely case that gdb
be used to COW a vDSO page - we ought to do something about that in
do_wp_page, but there are yet other inconsistencies to be resolved.
The safe and economical way to fix this is to let insert_vm_struct do
the security_vm_enough_memory check when it finds VM_ACCOUNT is set.
And the MIPS irix_brk has been calling security_vm_enough_memory before
calling do_brk which repeats it, doubly accounting and so also leaking.
Remove that, and all the fs and arch calls to security_vm_enough_memory:
give it a less misleading name later on.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-Off-By: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/ia64/ia32/binfmt_elf32.c b/arch/ia64/ia32/binfmt_elf32.c
index 31de70b..a7280d9 100644
--- a/arch/ia64/ia32/binfmt_elf32.c
+++ b/arch/ia64/ia32/binfmt_elf32.c
@@ -216,12 +216,6 @@
if (!mpnt)
return -ENOMEM;
- if (security_vm_enough_memory((IA32_STACK_TOP - (PAGE_MASK & (unsigned long) bprm->p))
- >> PAGE_SHIFT)) {
- kmem_cache_free(vm_area_cachep, mpnt);
- return -ENOMEM;
- }
-
memset(mpnt, 0, sizeof(*mpnt));
down_write(¤t->mm->mmap_sem);
diff --git a/arch/mips/kernel/sysirix.c b/arch/mips/kernel/sysirix.c
index 4de1556..7ae4af4 100644
--- a/arch/mips/kernel/sysirix.c
+++ b/arch/mips/kernel/sysirix.c
@@ -581,18 +581,13 @@
}
/*
- * Check if we have enough memory..
+ * Ok, looks good - let it rip.
*/
- if (security_vm_enough_memory((newbrk-oldbrk) >> PAGE_SHIFT)) {
+ if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) {
ret = -ENOMEM;
goto out;
}
-
- /*
- * Ok, looks good - let it rip.
- */
mm->brk = brk;
- do_brk(oldbrk, newbrk-oldbrk);
ret = 0;
out:
diff --git a/arch/ppc64/kernel/vdso.c b/arch/ppc64/kernel/vdso.c
index 4777676..efa985f 100644
--- a/arch/ppc64/kernel/vdso.c
+++ b/arch/ppc64/kernel/vdso.c
@@ -224,10 +224,7 @@
vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
if (vma == NULL)
return -ENOMEM;
- if (security_vm_enough_memory(vdso_pages)) {
- kmem_cache_free(vm_area_cachep, vma);
- return -ENOMEM;
- }
+
memset(vma, 0, sizeof(*vma));
/*
@@ -237,8 +234,10 @@
*/
vdso_base = get_unmapped_area(NULL, vdso_base,
vdso_pages << PAGE_SHIFT, 0, 0);
- if (vdso_base & ~PAGE_MASK)
+ if (vdso_base & ~PAGE_MASK) {
+ kmem_cache_free(vm_area_cachep, vma);
return (int)vdso_base;
+ }
current->thread.vdso_base = vdso_base;
@@ -266,7 +265,11 @@
vma->vm_ops = &vdso_vmops;
down_write(&mm->mmap_sem);
- insert_vm_struct(mm, vma);
+ if (insert_vm_struct(mm, vma)) {
+ up_write(&mm->mmap_sem);
+ kmem_cache_free(vm_area_cachep, vma);
+ return -ENOMEM;
+ }
mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
up_write(&mm->mmap_sem);
diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c
index c8131f3..d9161e3 100644
--- a/arch/x86_64/ia32/ia32_binfmt.c
+++ b/arch/x86_64/ia32/ia32_binfmt.c
@@ -353,11 +353,6 @@
mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
if (!mpnt)
return -ENOMEM;
-
- if (security_vm_enough_memory((IA32_STACK_TOP - (PAGE_MASK & (unsigned long) bprm->p))>>PAGE_SHIFT)) {
- kmem_cache_free(vm_area_cachep, mpnt);
- return -ENOMEM;
- }
memset(mpnt, 0, sizeof(*mpnt));
diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c
index adbc5f8..3a01329 100644
--- a/arch/x86_64/ia32/syscall32.c
+++ b/arch/x86_64/ia32/syscall32.c
@@ -52,17 +52,13 @@
vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
if (!vma)
return -ENOMEM;
- if (security_vm_enough_memory(npages)) {
- kmem_cache_free(vm_area_cachep, vma);
- return -ENOMEM;
- }
memset(vma, 0, sizeof(struct vm_area_struct));
/* Could randomize here */
vma->vm_start = VSYSCALL32_BASE;
vma->vm_end = VSYSCALL32_END;
/* MAYWRITE to allow gdb to COW and set breakpoints */
- vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYEXEC|VM_MAYWRITE;
+ vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
vma->vm_flags |= mm->def_flags;
vma->vm_page_prot = protection_map[vma->vm_flags & 7];
vma->vm_ops = &syscall32_vm_ops;
diff --git a/fs/exec.c b/fs/exec.c
index 6fae59a..a04a575 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -421,11 +421,6 @@
if (!mpnt)
return -ENOMEM;
- if (security_vm_enough_memory(arg_size >> PAGE_SHIFT)) {
- kmem_cache_free(vm_area_cachep, mpnt);
- return -ENOMEM;
- }
-
memset(mpnt, 0, sizeof(*mpnt));
down_write(&mm->mmap_sem);
diff --git a/mm/mmap.c b/mm/mmap.c
index 12334ae..8b8e05f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1993,6 +1993,9 @@
__vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
if (__vma && __vma->vm_start < vma->vm_end)
return -ENOMEM;
+ if ((vma->vm_flags & VM_ACCOUNT) &&
+ security_vm_enough_memory(vma_pages(vma)))
+ return -ENOMEM;
vma_link(mm, vma, prev, rb_link, rb_parent);
return 0;
}