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| author | akpm@osdl.org <akpm@osdl.org> | 2005-05-01 08:58:35 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-05-01 08:58:35 -0700 |
| commit | 119f657c72fc07d6fd28c61de59cfba1566970a9 (patch) | |
| tree | 33c8070aa904c4919cf244cdcd7c01e54589bb9e | |
| parent | f021e9210185b46e41ec3a0e78ec1621e168eacb (diff) | |
| download | linux-119f657c72fc07d6fd28c61de59cfba1566970a9.tar.gz linux-119f657c72fc07d6fd28c61de59cfba1566970a9.tar.bz2 linux-119f657c72fc07d6fd28c61de59cfba1566970a9.zip | |
[PATCH] RLIMIT_AS checking fix
Address bug #4508: there's potential for wraparound in the various places
where we perform RLIMIT_AS checking.
(I'm a bit worried about acct_stack_growth(). Are we sure that vma->vm_mm is
always equal to current->mm? If not, then we're comparing some other
process's total_vm with the calling process's rlimits).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | mm/mmap.c | 24 | ||||
| -rw-r--r-- | mm/mremap.c | 6 |
3 files changed, 23 insertions, 8 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index c74a74ca401d..8b007ad2d450 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -726,6 +726,7 @@ extern void __vma_link_rb(struct mm_struct *, struct vm_area_struct *, extern struct vm_area_struct *copy_vma(struct vm_area_struct **, unsigned long addr, unsigned long len, pgoff_t pgoff); extern void exit_mmap(struct mm_struct *); +extern int may_expand_vm(struct mm_struct *mm, unsigned long npages); extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); diff --git a/mm/mmap.c b/mm/mmap.c index 6ea204cc751e..1ec0f6e9c0d8 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1009,8 +1009,7 @@ munmap_back: } /* Check against address space limit. */ - if ((mm->total_vm << PAGE_SHIFT) + len - > current->signal->rlim[RLIMIT_AS].rlim_cur) + if (!may_expand_vm(mm, len >> PAGE_SHIFT)) return -ENOMEM; if (accountable && (!(flags & MAP_NORESERVE) || @@ -1421,7 +1420,7 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un struct rlimit *rlim = current->signal->rlim; /* address space limit tests */ - if (mm->total_vm + grow > rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT) + if (!may_expand_vm(mm, grow)) return -ENOMEM; /* Stack limit test */ @@ -1848,8 +1847,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len) } /* Check against address space limits *after* clearing old maps... */ - if ((mm->total_vm << PAGE_SHIFT) + len - > current->signal->rlim[RLIMIT_AS].rlim_cur) + if (!may_expand_vm(mm, len >> PAGE_SHIFT)) return -ENOMEM; if (mm->map_count > sysctl_max_map_count) @@ -2019,3 +2017,19 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, } return new_vma; } + +/* + * Return true if the calling process may expand its vm space by the passed + * number of pages + */ +int may_expand_vm(struct mm_struct *mm, unsigned long npages) +{ + unsigned long cur = mm->total_vm; /* pages */ + unsigned long lim; + + lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; + + if (cur + npages > lim) + return 0; + return 1; +} diff --git a/mm/mremap.c b/mm/mremap.c index 0d1c1b9c7a0a..0dd7ace94e51 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -347,10 +347,10 @@ unsigned long do_mremap(unsigned long addr, if (locked > lock_limit && !capable(CAP_IPC_LOCK)) goto out; } - ret = -ENOMEM; - if ((current->mm->total_vm << PAGE_SHIFT) + (new_len - old_len) - > current->signal->rlim[RLIMIT_AS].rlim_cur) + if (!may_expand_vm(current->mm, (new_len - old_len) >> PAGE_SHIFT)) { + ret = -ENOMEM; goto out; + } if (vma->vm_flags & VM_ACCOUNT) { charged = (new_len - old_len) >> PAGE_SHIFT; |