Re: [BUGFIX] NULL pointer dereference in __vm_enough_memory()
From: Cyrill Gorcunov
Date: Sun Aug 12 2007 - 12:22:12 EST
[Alan Cox - Sun, Aug 12, 2007 at 04:17:44PM +0100]
| Try this (it compiles but isnt tested). Its a weekend here, the sun is
| shining, the beach is a short walk, and I have more interesting things to
| do right now 8)
|
|
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/include/linux/mm.h linux-2.6.23rc1-mm1/include/linux/mm.h
| --- linux.vanilla-2.6.23rc1-mm1/include/linux/mm.h 2007-07-26 15:02:58.000000000 +0100
| +++ linux-2.6.23rc1-mm1/include/linux/mm.h 2007-08-12 13:54:24.614647536 +0100
| @@ -1079,7 +1079,7 @@
| }
|
| /* mmap.c */
| -extern int __vm_enough_memory(long pages, int cap_sys_admin);
| +extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
| extern void vma_adjust(struct vm_area_struct *vma, unsigned long start,
| unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert);
| extern struct vm_area_struct *vma_merge(struct mm_struct *,
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/include/linux/security.h linux-2.6.23rc1-mm1/include/linux/security.h
| --- linux.vanilla-2.6.23rc1-mm1/include/linux/security.h 2007-07-26 15:02:58.000000000 +0100
| +++ linux-2.6.23rc1-mm1/include/linux/security.h 2007-08-12 14:13:10.383504656 +0100
| @@ -58,7 +58,7 @@
| extern int cap_task_setioprio (struct task_struct *p, int ioprio);
| extern int cap_task_setnice (struct task_struct *p, int nice);
| extern int cap_syslog (int type);
| -extern int cap_vm_enough_memory (long pages);
| +extern int cap_vm_enough_memory (struct mm_struct *mm, long pages);
|
| struct msghdr;
| struct sk_buff;
| @@ -1129,6 +1129,7 @@
| * Return 0 if permission is granted.
| * @vm_enough_memory:
| * Check permissions for allocating a new virtual mapping.
| + * @mm contains the mm struct it is being added to.
| * @pages contains the number of pages.
| * Return 0 if permission is granted.
| *
| @@ -1173,7 +1174,7 @@
| int (*quota_on) (struct dentry * dentry);
| int (*syslog) (int type);
| int (*settime) (struct timespec *ts, struct timezone *tz);
| - int (*vm_enough_memory) (long pages);
| + int (*vm_enough_memory) (struct mm_struct *mm, long pages);
|
| int (*bprm_alloc_security) (struct linux_binprm * bprm);
| void (*bprm_free_security) (struct linux_binprm * bprm);
| @@ -1439,6 +1440,7 @@
| int security_syslog(int type);
| int security_settime(struct timespec *ts, struct timezone *tz);
| int security_vm_enough_memory(long pages);
| +int security_vm_enough_memory_mm(struct mm_struct *mm, long pages);
| int security_bprm_alloc(struct linux_binprm *bprm);
| void security_bprm_free(struct linux_binprm *bprm);
| void security_bprm_apply_creds(struct linux_binprm *bprm, int unsafe);
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/mm/mmap.c linux-2.6.23rc1-mm1/mm/mmap.c
| --- linux.vanilla-2.6.23rc1-mm1/mm/mmap.c 2007-07-26 15:02:58.000000000 +0100
| +++ linux-2.6.23rc1-mm1/mm/mmap.c 2007-08-12 13:53:22.000000000 +0100
| @@ -93,7 +93,7 @@
| * Note this is a helper function intended to be used by LSMs which
| * wish to use this logic.
| */
| -int __vm_enough_memory(long pages, int cap_sys_admin)
| +int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
| {
| unsigned long free, allowed;
|
| @@ -166,7 +166,7 @@
|
| /* Don't let a single process grow too big:
| leave 3% of the size of this process for other processes */
| - allowed -= current->mm->total_vm / 32;
| + allowed -= mm->total_vm / 32;
So mm->total_vm is 0 for __bprm_mm_init case. Is that ok? Or I miss
something?
|
| /*
| * cast `allowed' as a signed long because vm_committed_space
| @@ -2058,7 +2058,7 @@
| if (__vma && __vma->vm_start < vma->vm_end)
| return -ENOMEM;
| if ((vma->vm_flags & VM_ACCOUNT) &&
| - security_vm_enough_memory(vma_pages(vma)))
| + security_vm_enough_memory_mm(mm, vma_pages(vma)))
| return -ENOMEM;
| vma_link(mm, vma, prev, rb_link, rb_parent);
| return 0;
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/mm/nommu.c linux-2.6.23rc1-mm1/mm/nommu.c
| --- linux.vanilla-2.6.23rc1-mm1/mm/nommu.c 2007-07-26 15:02:08.000000000 +0100
| +++ linux-2.6.23rc1-mm1/mm/nommu.c 2007-08-12 13:53:57.000000000 +0100
| @@ -1270,7 +1270,7 @@
| * Note this is a helper function intended to be used by LSMs which
| * wish to use this logic.
| */
| -int __vm_enough_memory(long pages, int cap_sys_admin)
| +int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
| {
| unsigned long free, allowed;
|
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/security/commoncap.c linux-2.6.23rc1-mm1/security/commoncap.c
| --- linux.vanilla-2.6.23rc1-mm1/security/commoncap.c 2007-07-26 15:02:59.000000000 +0100
| +++ linux-2.6.23rc1-mm1/security/commoncap.c 2007-08-12 14:13:29.000000000 +0100
| @@ -489,13 +489,13 @@
| return 0;
| }
|
| -int cap_vm_enough_memory(long pages)
| +int cap_vm_enough_memory(struct mm_struct *mm, long pages)
| {
| int cap_sys_admin = 0;
|
| if (cap_capable(current, CAP_SYS_ADMIN) == 0)
| cap_sys_admin = 1;
| - return __vm_enough_memory(pages, cap_sys_admin);
| + return __vm_enough_memory(mm, pages, cap_sys_admin);
| }
|
| EXPORT_SYMBOL(cap_capable);
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/security/dummy.c linux-2.6.23rc1-mm1/security/dummy.c
| --- linux.vanilla-2.6.23rc1-mm1/security/dummy.c 2007-07-26 15:02:59.000000000 +0100
| +++ linux-2.6.23rc1-mm1/security/dummy.c 2007-08-12 14:10:49.000000000 +0100
| @@ -107,13 +107,13 @@
| return 0;
| }
|
| -static int dummy_vm_enough_memory(long pages)
| +static int dummy_vm_enough_memory(struct mm_struct *mm, long pages)
| {
| int cap_sys_admin = 0;
|
| if (dummy_capable(current, CAP_SYS_ADMIN) == 0)
| cap_sys_admin = 1;
| - return __vm_enough_memory(pages, cap_sys_admin);
| + return __vm_enough_memory(mm, pages, cap_sys_admin);
| }
|
| static int dummy_bprm_alloc_security (struct linux_binprm *bprm)
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/security/security.c linux-2.6.23rc1-mm1/security/security.c
| --- linux.vanilla-2.6.23rc1-mm1/security/security.c 2007-07-26 15:02:59.000000000 +0100
| +++ linux-2.6.23rc1-mm1/security/security.c 2007-08-12 13:47:53.000000000 +0100
| @@ -237,10 +237,14 @@
| return security_ops->settime(ts, tz);
| }
|
| -
| int security_vm_enough_memory(long pages)
| {
| - return security_ops->vm_enough_memory(pages);
| + return security_ops->vm_enough_memory(current->mm, pages);
| +}
| +
| +int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
| +{
| + return security_ops->vm_enough_memory(mm, pages);
| }
|
| int security_bprm_alloc(struct linux_binprm *bprm)
| diff -u --new-file --recursive --exclude-from /usr/src/exclude linux.vanilla-2.6.23rc1-mm1/security/selinux/hooks.c linux-2.6.23rc1-mm1/security/selinux/hooks.c
| --- linux.vanilla-2.6.23rc1-mm1/security/selinux/hooks.c 2007-07-26 15:02:59.000000000 +0100
| +++ linux-2.6.23rc1-mm1/security/selinux/hooks.c 2007-08-12 14:11:21.000000000 +0100
| @@ -1584,7 +1584,7 @@
| * Do not audit the selinux permission check, as this is applied to all
| * processes that allocate mappings.
| */
| -static int selinux_vm_enough_memory(long pages)
| +static int selinux_vm_enough_memory(struct mm_struct *mm, long pages)
| {
| int rc, cap_sys_admin = 0;
| struct task_security_struct *tsec = current->security;
| @@ -1600,7 +1600,7 @@
| if (rc == 0)
| cap_sys_admin = 1;
|
| - return __vm_enough_memory(pages, cap_sys_admin);
| + return __vm_enough_memory(mm, pages, cap_sys_admin);
| }
|
| /* binprm security operations */
Cyrill
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