]> git.baikalelectronics.ru Git - kernel.git/commitdiff
exec: Use secureexec for setting dumpability
authorKees Cook <keescook@chromium.org>
Tue, 18 Jul 2017 22:25:31 +0000 (15:25 -0700)
committerKees Cook <keescook@chromium.org>
Tue, 1 Aug 2017 19:03:10 +0000 (12:03 -0700)
The examination of "current" to decide dumpability is wrong. This was a
check of and euid/uid (or egid/gid) mismatch in the existing process,
not the newly created one. This appears to stretch back into even the
"history.git" tree. Luckily, dumpability is later set in commit_creds().
In earlier kernel versions before creds existed, similar checks also
existed late in the exec flow, covering up the mistake as far back as I
could find.

Note that because the commit_creds() check examines differences of euid,
uid, egid, gid, and capabilities between the old and new creds, it would
look like the setup_new_exec() dumpability test could be entirely removed.
However, the secureexec test may cover a different set of tests (specific
to the LSMs) than what commit_creds() checks for. So, fix this test to
use secureexec (the removed euid tests are redundant to the commoncap
secureexec checks now).

Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
fs/exec.c

index eca0cb550a06392c4689643dedf7149c1913bef4..3536437ffd762201da7a98d29f341759651c466c 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1354,7 +1354,7 @@ void setup_new_exec(struct linux_binprm * bprm)
 
        current->sas_ss_sp = current->sas_ss_size = 0;
 
-       if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid()))
+       if (!bprm->secureexec)
                set_dumpable(current->mm, SUID_DUMP_USER);
        else
                set_dumpable(current->mm, suid_dumpable);