From 731572d39fcd3498702eda4600db4c43d51e0b26 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 29 Oct 2008 14:01:20 -0700 Subject: nfsd: fix vm overcommit crash 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 Acked-by: James Morris Signed-off-by: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/security.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/security.h b/include/linux/security.h index f5c4a51eb42e..c13f1cec9abb 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -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); -- cgit v1.2.3