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fix NULL pointer dereference in __vm_enough_memory()

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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 <alan@redhat.com>
Cc: WU Fengguang <wfg@mail.ustc.edu.cn>
Cc: James Morris <jmorris@redhat.com>
Cc: Tobias Diedrich <ranma+kernel@tdiedrich.de>
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
2007-08-22 14:01:28 -07:00
committed by Linus Torvalds
parent afe1ab4d57
commit 34b4e4aa3c
7 changed files with 26 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
security/commoncap.c
View File

@ -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);

4
security/dummy.c
View File

@ -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)

4
security/selinux/hooks.c
View File

@ -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 */