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charset=us-ascii Content-Disposition: inline X-Stat-Signature: jffnuokudecmo89i36q8uuqsbs4ne56u X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 98CD0180010 X-Rspam-User: X-HE-Tag: 1779806548-731100 X-HE-Meta: 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 ZGG0SCdE 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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(). Signed-off-by: Oleg Nesterov --- mm/migrate.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 8a64291ab5b4..e4cf664fb161 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2557,24 +2557,29 @@ 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) -- 2.52.0