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authorAlan Cox <alan@redhat.com>2008-10-29 17:01:20 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-30 14:38:47 -0400
commit731572d39fcd3498702eda4600db4c43d51e0b26 (patch)
treef892907ae20539845f353d72d2a2bf202b67e007 /security/security.c
parent6c89161b10f5771ee0b51ada0fce0e8835e72ade (diff)
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 <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>
Diffstat (limited to 'security/security.c')
-rw-r--r--security/security.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c
index 255b08559b2b..c0acfa7177e5 100644
--- a/security/security.c
+++ b/security/security.c
@@ -198,14 +198,23 @@ int security_settime(struct timespec *ts, struct timezone *tz)
198 198
199int security_vm_enough_memory(long pages) 199int security_vm_enough_memory(long pages)
200{ 200{
201 WARN_ON(current->mm == NULL);
201 return security_ops->vm_enough_memory(current->mm, pages); 202 return security_ops->vm_enough_memory(current->mm, pages);
202} 203}
203 204
204int security_vm_enough_memory_mm(struct mm_struct *mm, long pages) 205int security_vm_enough_memory_mm(struct mm_struct *mm, long pages)
205{ 206{
207 WARN_ON(mm == NULL);
206 return security_ops->vm_enough_memory(mm, pages); 208 return security_ops->vm_enough_memory(mm, pages);
207} 209}
208 210
211int security_vm_enough_memory_kern(long pages)
212{
213 /* If current->mm is a kernel thread then we will pass NULL,
214 for this specific case that is fine */
215 return security_ops->vm_enough_memory(current->mm, pages);
216}
217
209int security_bprm_alloc(struct linux_binprm *bprm) 218int security_bprm_alloc(struct linux_binprm *bprm)
210{ 219{
211 return security_ops->bprm_alloc_security(bprm); 220 return security_ops->bprm_alloc_security(bprm);