GitHub-Mirror/linux-bl808
2
0
Fork 0
mirror of https://github.com/Fishwaldo/linux-bl808.git synced 2025-06-17 20:25:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

nfsd: fix vm overcommit crash

Browse source 
Junjiro R.  Okajima reported a problem where knfsd crashes if you are
using it to export shmemfs objects and run strict overcommit.  In this
situation the current->mm based modifier to the overcommit goes through a
NULL pointer.

We could simply check for NULL and skip the modifier but we've caught
other real bugs in the past from mm being NULL here - cases where we did
need a valid mm set up (eg the exec bug about a year ago).

To preserve the checks and get the logic we want shuffle the checking
around and add a new helper to the vm_ security wrappers

Also fix a current->mm reference in nommu that should use the passed mm

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix build]
Reported-by: Junjiro R. Okajima <hooanon05@yahoo.co.jp>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox 2008-10-29 14:01:20 -07:00 • committed by Linus Torvalds
parent 6c89161b10
commit 731572d39f
5 changed files with 23 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

6
include/linux/security.h
View file

@ -1585,6 +1585,7 @@ 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_vm_enough_memory_kern(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);
@ -1820,6 +1821,11 @@ static inline int security_vm_enough_memory(long pages)
return cap_vm_enough_memory(current->mm, pages);
}
static inline int security_vm_enough_memory_kern(long pages)
{
return cap_vm_enough_memory(current->mm, pages);
}
static inline int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
{
return cap_vm_enough_memory(mm, pages);