mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-07-16 17:57:38 -04:00
Code Issues Packages Projects Releases Wiki Activity

mm/migrate: find_mm_struct: fix race between security checks and suid exec

Browse Source 
The target task can execute a setuid binary between ptrace_may_access()
and get_task_mm().  Protect this critical section with exec_update_lock.

I don't think cpuset_mems_allowed(task) should be called under
exec_update_lock, but this patch just tries to add the minimal fix.

Perhaps we can later add a common helper which can be used by
find_mm_struct() and kernel_migrate_pages().

Link: https://lore.kernel.org/ahWxQ3JxdR5ff2qf@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Oleg Nesterov
2026-05-26 16:42:11 +02:00
committed by Andrew Morton
parent 9c87962f85
commit 13f77972b9
1 changed files with 9 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
mm/migrate.c
View File

@@ -2555,24 +2555,29 @@ static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes)
}
task = find_get_task_by_vpid(pid);
if (!task) {
if (!task)
return ERR_PTR(-ESRCH);
}
if (down_read_killable(&task->signal->exec_update_lock)) {
mm = ERR_PTR(-EINTR);
goto out;
}
/*
* Check if this process has the right to modify the specified
* process. Use the regular "ptrace_may_access()" checks.
*/
if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
mm = ERR_PTR(-EPERM);
goto out;
goto unlock;
}
mm = ERR_PTR(security_task_movememory(task));
if (IS_ERR(mm))
goto out;
goto unlock;
*mem_nodes = cpuset_mems_allowed(task);
mm = get_task_mm(task);
unlock:
up_read(&task->signal->exec_update_lock);
out:
put_task_struct(task);
if (!mm)