Commit-ID: d17af5056cf9e9fc05e68832f7c15687fcc12281 Gitweb: http://git.kernel.org/tip/d17af5056cf9e9fc05e68832f7c15687fcc12281 Author: Andy Lutomirski <[email protected]> AuthorDate: Fri, 30 Sep 2016 10:58:58 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Thu, 20 Oct 2016 09:21:41 +0200
mm: Change vm_is_stack_for_task() to vm_is_stack_for_current() Asking for a non-current task's stack can't be done without races unless the task is frozen in kernel mode. As far as I know, vm_is_stack_for_task() never had a safe non-current use case. The __unused annotation is because some KSTK_ESP implementations ignore their parameter, which IMO is further justification for this patch. Signed-off-by: Andy Lutomirski <[email protected]> Acked-by: Thomas Gleixner <[email protected]> Cc: Al Viro <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Jann Horn <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Linux API <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Tycho Andersen <[email protected]> Link: http://lkml.kernel.org/r/4c3f68f426e6c061ca98b4fc7ef85ffbb0a25b0c.1475257877.git.l...@kernel.org Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/mm.h | 2 +- mm/util.c | 4 +++- security/selinux/hooks.c | 2 +- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index e9caec6..a658a51 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1391,7 +1391,7 @@ static inline int stack_guard_page_end(struct vm_area_struct *vma, !vma_growsup(vma->vm_next, addr); } -int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t); +int vma_is_stack_for_current(struct vm_area_struct *vma); extern unsigned long move_page_tables(struct vm_area_struct *vma, unsigned long old_addr, struct vm_area_struct *new_vma, diff --git a/mm/util.c b/mm/util.c index 662cddf..c174e89 100644 --- a/mm/util.c +++ b/mm/util.c @@ -230,8 +230,10 @@ void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, } /* Check if the vma is being used as a stack by this task */ -int vma_is_stack_for_task(struct vm_area_struct *vma, struct task_struct *t) +int vma_is_stack_for_current(struct vm_area_struct *vma) { + struct task_struct * __maybe_unused t = current; + return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); } diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 0850579..09fd610 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3557,7 +3557,7 @@ static int selinux_file_mprotect(struct vm_area_struct *vma, } else if (!vma->vm_file && ((vma->vm_start <= vma->vm_mm->start_stack && vma->vm_end >= vma->vm_mm->start_stack) || - vma_is_stack_for_task(vma, current))) { + vma_is_stack_for_current(vma))) { rc = current_has_perm(current, PROCESS__EXECSTACK); } else if (vma->vm_file && vma->anon_vma) { /*
