CRED: Use RCU to access another task's creds and to release a task's own creds

[mirror_ubuntu-bionic-kernel.git] / fs / binfmt_elf.c

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 0e6655613169493b28c299c688396545b62319e4..9142ff5dc8e644d15de7f6897d195df6d58f6c6a 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1361,6 +1361,7 @@ static void fill_prstatus(struct elf_prstatus *prstatus,
 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
                       struct mm_struct *mm)
 {
+       const struct cred *cred;
        unsigned int i, len;
        
        /* first copy the parameters from user space */
@@ -1388,8 +1389,11 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
        psinfo->pr_zomb = psinfo->pr_sname == 'Z';
        psinfo->pr_nice = task_nice(p);
        psinfo->pr_flag = p->flags;
-       SET_UID(psinfo->pr_uid, p->cred->uid);
-       SET_GID(psinfo->pr_gid, p->cred->gid);
+       rcu_read_lock();
+       cred = __task_cred(p);
+       SET_UID(psinfo->pr_uid, cred->uid);
+       SET_GID(psinfo->pr_gid, cred->gid);
+       rcu_read_unlock();
        strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
        
        return 0;