do_coredump(): make sure that descriptor table isn't shared

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 3fc74681cc6c..beb05a95e4a3 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -2066,6 +2066,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
         int retval = 0;
         int flag = 0;
         int ispipe;
+        struct files_struct *displaced;
         bool need_nonrelative = false;
         static atomic_t core_dump_count = ATOMIC_INIT(0);
         struct coredump_params cprm = {
@@ -2219,6 +2220,12 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs)
                         goto close_fail;
         }
 
+        /* get us an unshared descriptor table; almost always a no-op */
+        retval = unshare_files(&displaced);
+        if (retval)
+                goto close_fail;
+        if (displaced)
+                put_files_struct(displaced);
         retval = binfmt->core_dump(&cprm);
         if (retval)
                 current->signal->group_exit_code |= 0x80;