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[PATCH] error path in setup_arg_pages() misses vm_unacct_memory()

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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>
This commit is contained in:
Hugh Dickins 2005-09-14 06:13:02 +01:00 committed by Linus Torvalds
parent fb085cf1d4
commit 2fd4ef85e0
7 changed files with 15 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/ia64/ia32/binfmt_elf32.c
View File

@ -216,12 +216,6 @@ ia32_setup_arg_pages (struct linux_binprm *bprm, int executable_stack)
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(&current->mm->mmap_sem);

9
arch/mips/kernel/sysirix.c
View File

@ -581,18 +581,13 @@ asmlinkage int irix_brk(unsigned long brk)
}
/*
* 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:

15
arch/ppc64/kernel/vdso.c
View File

@ -224,10 +224,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int executable_stack)
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 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int executable_stack)
*/
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 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int executable_stack)
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);

5
arch/x86_64/ia32/ia32_binfmt.c
View File

@ -354,11 +354,6 @@ int setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top, int exec
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(&mm->mmap_sem);

6
arch/x86_64/ia32/syscall32.c
View File

@ -52,17 +52,13 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
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;

5
fs/exec.c
View File

@ -421,11 +421,6 @@ int setup_arg_pages(struct linux_binprm *bprm,
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);

3
mm/mmap.c
View File

@ -1993,6 +1993,9 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
__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;
}