UBUNTU: Ubuntu-4.13.0-45.50

[mirror_ubuntu-artful-kernel.git] / fs / exec.c

diff --git a/fs/exec.c b/fs/exec.c
index f52e74b3c429f18d1771e50fd65efe5d0d7bf7b4..0f47bb84860c3a79e7c4fe0f4425459b665cff13 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -62,6 +62,7 @@
 #include <linux/oom.h>
 #include <linux/compat.h>
 #include <linux/vmalloc.h>
+#include <linux/delay.h>
 
 #include <trace/events/fs.h>
 
@@ -111,6 +112,7 @@ bool path_noexec(const struct path *path)
        return (path->mnt->mnt_flags & MNT_NOEXEC) ||
               (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
 }
+EXPORT_SYMBOL_GPL(path_noexec);
 
 bool path_nosuid(const struct path *path)
 {
@@ -1463,6 +1465,8 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 {
        struct task_struct *p = current, *t;
        unsigned n_fs;
+       bool fs_recheck;
+       int count = 0;
 
        if (p->ptrace)
                bprm->unsafe |= LSM_UNSAFE_PTRACE;
@@ -1474,6 +1478,8 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
        if (task_no_new_privs(current))
                bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
 
+recheck:
+       fs_recheck = false;
        t = p;
        n_fs = 1;
        spin_lock(&p->fs->lock);
@@ -1481,12 +1487,21 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
        while_each_thread(p, t) {
                if (t->fs == p->fs)
                        n_fs++;
+               if (t->flags & (PF_EXITING | PF_FORKNOEXEC))
+                       fs_recheck  = true;
        }
        rcu_read_unlock();
 
-       if (p->fs->users > n_fs)
+       if (p->fs->users > n_fs) {
+               if (fs_recheck) {
+                       if (count++ < 20) {
+                               spin_unlock(&p->fs->lock);
+                               msleep_interruptible(1);
+                               goto recheck;
+                       }
+               }
                bprm->unsafe |= LSM_UNSAFE_SHARE;
-       else
+       } else
                p->fs->in_exec = 1;
        spin_unlock(&p->fs->lock);
 }