Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=34b4e4aa3c470ce8fa2bd78abb1741b4b58baad7
Commit:     34b4e4aa3c470ce8fa2bd78abb1741b4b58baad7
Parent:     afe1ab4d577892822de2c8e803fbfaed6ec44ba3
Author:     Alan Cox <[EMAIL PROTECTED]>
AuthorDate: Wed Aug 22 14:01:28 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Aug 22 19:52:45 2007 -0700

    fix NULL pointer dereference in __vm_enough_memory()
    
    The new exec code inserts an accounted vma into an mm struct which is not
    current->mm.  The existing memory check code has a hard coded assumption
    that this does not happen as does the security code.
    
    As the correct mm is known we pass the mm to the security method and the
    helper function.  A new security test is added for the case where we need
    to pass the mm and the existing one is modified to pass current->mm to
    avoid the need to change large amounts of code.
    
    (Thanks to Tobias for fixing rejects and testing)
    
    Signed-off-by: Alan Cox <[EMAIL PROTECTED]>
    Cc: WU Fengguang <[EMAIL PROTECTED]>
    Cc: James Morris <[EMAIL PROTECTED]>
    Cc: Tobias Diedrich <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 include/linux/mm.h       |    2 +-
 include/linux/security.h |   20 +++++++++++++++-----
 mm/mmap.c                |    6 +++---
 mm/nommu.c               |    2 +-
 security/commoncap.c     |    4 ++--
 security/dummy.c         |    4 ++--
 security/selinux/hooks.c |    4 ++--
 7 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 655094d..1692dd6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1042,7 +1042,7 @@ static inline void vma_nonlinear_insert(struct 
vm_area_struct *vma,
 }
 
 /* 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 --git a/include/linux/security.h b/include/linux/security.h
index c11dc8a..1a15526 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -54,7 +54,7 @@ extern int cap_inode_removexattr(struct dentry *dentry, char 
*name);
 extern int cap_task_post_setuid (uid_t old_ruid, uid_t old_euid, uid_t 
old_suid, int flags);
 extern void cap_task_reparent_to_init (struct task_struct *p);
 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;
@@ -1125,6 +1125,7 @@ struct request_sock;
  *     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.
  *
@@ -1169,7 +1170,7 @@ struct security_operations {
        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);
@@ -1469,10 +1470,14 @@ static inline int security_settime(struct timespec *ts, 
struct timezone *tz)
        return security_ops->settime(ts, tz);
 }
 
-
 static inline int security_vm_enough_memory(long pages)
 {
-       return security_ops->vm_enough_memory(pages);
+       return security_ops->vm_enough_memory(current->mm, pages);
+}
+
+static inline int security_vm_enough_memory_mm(struct mm_struct *mm, long 
pages)
+{
+       return security_ops->vm_enough_memory(mm, pages);
 }
 
 static inline int security_bprm_alloc (struct linux_binprm *bprm)
@@ -2219,7 +2224,12 @@ static inline int security_settime(struct timespec *ts, 
struct timezone *tz)
 
 static inline int security_vm_enough_memory(long pages)
 {
-       return cap_vm_enough_memory(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);
 }
 
 static inline int security_bprm_alloc (struct linux_binprm *bprm)
diff --git a/mm/mmap.c b/mm/mmap.c
index b653721..0d40e66 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -93,7 +93,7 @@ atomic_t vm_committed_space = ATOMIC_INIT(0);
  * 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 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
 
        /* 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;
 
        /*
         * cast `allowed' as a signed long because vm_committed_space
@@ -2077,7 +2077,7 @@ int insert_vm_struct(struct mm_struct * mm, struct 
vm_area_struct * vma)
        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 --git a/mm/nommu.c b/mm/nommu.c
index 9eef6a3..8ed0cb4 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1270,7 +1270,7 @@ EXPORT_SYMBOL(get_unmapped_area);
  * 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 --git a/security/commoncap.c b/security/commoncap.c
index 338606e..7520361 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -315,13 +315,13 @@ int cap_syslog (int type)
        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 --git a/security/dummy.c b/security/dummy.c
index 19d813d..853ec22 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -108,13 +108,13 @@ static int dummy_settime(struct timespec *ts, struct 
timezone *tz)
        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 --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 6237933..d8bc417 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1584,7 +1584,7 @@ static int selinux_syslog(int type)
  * 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 @@ static int selinux_vm_enough_memory(long pages)
        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 */
-
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