From: Kees Cook <keescook@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
David Howells <dhowells@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
John Johansen <john.johansen@canonical.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
Paul Moore <paul@paul-moore.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
Casey Schaufler <casey@schaufler-ca.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
James Morris <james.l.morris@oracle.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v4 10/15] exec: Use secureexec for setting dumpability
Date: Mon, 31 Jul 2017 16:51:28 -0700 [thread overview]
Message-ID: <1501545093-56634-11-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1501545093-56634-1-git-send-email-keescook@chromium.org>
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>
---
fs/exec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/exec.c b/fs/exec.c
index f0e8d25eba9f..f9997ea6414e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1333,7 +1333,7 @@ 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);
--
2.7.4
next prev parent reply other threads:[~2017-07-31 23:51 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 23:51 [PATCH v4 00/15] exec: Use sane stack rlimit under secureexec Kees Cook
2017-07-31 23:51 ` [PATCH v4 01/15] exec: Rename bprm->cred_prepared to called_set_creds Kees Cook
2017-07-31 23:51 ` [PATCH v4 02/15] exec: Correct comments about "point of no return" Kees Cook
2017-07-31 23:51 ` [PATCH v4 03/15] binfmt: Introduce secureexec flag Kees Cook
2017-08-01 0:23 ` Kees Cook
2017-08-01 0:44 ` James Morris
2017-07-31 23:51 ` [PATCH v4 04/15] apparmor: Refactor to remove bprm_secureexec hook Kees Cook
2017-07-31 23:51 ` [PATCH v4 05/15] selinux: " Kees Cook
2017-08-01 0:45 ` James Morris
2017-08-01 13:24 ` Andy Lutomirski
2017-07-31 23:51 ` [PATCH v4 06/15] smack: " Kees Cook
2017-08-01 0:46 ` James Morris
2017-08-01 15:24 ` Casey Schaufler
2017-07-31 23:51 ` [PATCH v4 07/15] commoncap: " Kees Cook
2017-07-31 23:51 ` [PATCH v4 08/15] commoncap: Move cap_elevated calculation into bprm_set_creds Kees Cook
2017-08-01 13:46 ` Andy Lutomirski
2017-07-31 23:51 ` [PATCH v4 09/15] LSM: drop bprm_secureexec hook Kees Cook
2017-07-31 23:51 ` Kees Cook [this message]
2017-08-01 0:48 ` [PATCH v4 10/15] exec: Use secureexec for setting dumpability James Morris
2017-07-31 23:51 ` [PATCH v4 11/15] exec: Use secureexec for clearing pdeath_signal Kees Cook
2017-08-01 0:50 ` James Morris
2017-07-31 23:51 ` [PATCH v4 12/15] smack: Remove redundant pdeath_signal clearing Kees Cook
2017-08-01 0:50 ` James Morris
2017-08-01 15:24 ` Casey Schaufler
2017-07-31 23:51 ` [PATCH v4 13/15] exec: Consolidate dumpability logic Kees Cook
2017-07-31 23:51 ` [PATCH v4 14/15] exec: Use sane stack rlimit under secureexec Kees Cook
2017-07-31 23:51 ` [PATCH v4 15/15] exec: Consolidate pdeath_signal clearing Kees Cook
2017-08-01 0:52 ` James Morris
2017-08-01 0:34 ` [PATCH v4 00/15] exec: Use sane stack rlimit under secureexec Kees Cook
2017-08-01 0:54 ` James Morris
2017-08-01 3:03 ` Kees Cook
2017-08-01 5:11 ` Linus Torvalds
2017-08-01 5:14 ` Linus Torvalds
2017-08-01 15:04 ` Kees Cook
2017-08-01 20:19 ` Linus Torvalds
2017-08-01 21:04 ` Kees Cook
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