From a35547da680829ce9036a476678a5fd4bfa59a6b Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Fri, 28 Aug 2009 14:08:17 +0200 Subject: [PATCH] core: allow setrlimit to non-current tasks References: FATE#305733 Patch-mainline: no (later) Add locking to allow setrlimit accept task parameter other than current. Namely, lock tasklist_lock for read and check whether the task structure has sighand non-null. Do all the signal processing under that lock still held. Signed-off-by: Jiri Slaby Cc: Oleg Nesterov --- kernel/sys.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1302,6 +1302,7 @@ SYSCALL_DEFINE2(old_getrlimit, unsigned #endif +/* make sure you are allowed to change @tsk limits before calling this */ int do_setrlimit(struct task_struct *tsk, unsigned int resource, struct rlimit *new_rlim) { @@ -1315,9 +1316,16 @@ int do_setrlimit(struct task_struct *tsk if (resource == RLIMIT_NOFILE && new_rlim->rlim_max > sysctl_nr_open) return -EPERM; + /* protect tsk->signal and tsk->sighand from disappearing */ + read_lock(&tasklist_lock); + if (!tsk->sighand) { + retval = -ESRCH; + goto out; + } + retval = security_task_setrlimit(tsk, resource, new_rlim); if (retval) - return retval; + goto out; if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { /* @@ -1352,6 +1360,7 @@ int do_setrlimit(struct task_struct *tsk update_rlimit_cpu(tsk, new_rlim->rlim_cur); out: + read_unlock(&tasklist_lock); return retval; }