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-fsdevel@vger.kernel.org>, linux-security-module <linux-security-module@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH v3 10/15] exec: Use secureexec for setting dumpability Date: Tue, 25 Jul 2017 20:59:15 -0700 [thread overview] Message-ID: <CAGXu5jJe5PB8Cof4GomKa6HO28ioCDtGjhcSH6Ruy0RvAZ+R8A@mail.gmail.com> (raw) In-Reply-To: <1500416736-49829-11-git-send-email-keescook@chromium.org> On Tue, Jul 18, 2017 at 3:25 PM, Kees Cook <keescook@chromium.org> wrote: > 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> David (or anyone else), how does this (and the following undiscussed patches) look? I only have a few unreviewed patches in this series, and I'd like to get some more eyes on it. Thanks! -Kees > --- > fs/exec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/exec.c b/fs/exec.c > index f9480d3e0b82..5241c8f25f5d 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -1353,7 +1353,7 @@ 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 > -- Kees Cook Pixel Security
WARNING: multiple messages have this Message-ID (diff)
From: keescook@chromium.org (Kees Cook) To: linux-security-module@vger.kernel.org Subject: [PATCH v3 10/15] exec: Use secureexec for setting dumpability Date: Tue, 25 Jul 2017 20:59:15 -0700 [thread overview] Message-ID: <CAGXu5jJe5PB8Cof4GomKa6HO28ioCDtGjhcSH6Ruy0RvAZ+R8A@mail.gmail.com> (raw) In-Reply-To: <1500416736-49829-11-git-send-email-keescook@chromium.org> On Tue, Jul 18, 2017 at 3:25 PM, Kees Cook <keescook@chromium.org> wrote: > 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> David (or anyone else), how does this (and the following undiscussed patches) look? I only have a few unreviewed patches in this series, and I'd like to get some more eyes on it. Thanks! -Kees > --- > fs/exec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/exec.c b/fs/exec.c > index f9480d3e0b82..5241c8f25f5d 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -1353,7 +1353,7 @@ 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 > -- Kees Cook Pixel Security -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2017-07-26 3:59 UTC|newest] Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-07-18 22:25 [PATCH v3 00/15] exec: Use sane stack rlimit under secureexec Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-18 22:25 ` [PATCH v3 01/15] binfmt: Introduce secureexec flag Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 0:05 ` John Johansen 2017-07-19 0:05 ` John Johansen 2017-07-19 1:01 ` Andy Lutomirski 2017-07-19 1:01 ` Andy Lutomirski 2017-07-18 22:25 ` [PATCH v3 02/15] exec: Rename bprm->cred_prepared to called_set_creds Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 0:08 ` John Johansen 2017-07-19 0:08 ` John Johansen 2017-07-19 1:06 ` Andy Lutomirski 2017-07-19 1:06 ` Andy Lutomirski 2017-07-19 4:40 ` Kees Cook 2017-07-19 4:40 ` Kees Cook 2017-07-19 9:19 ` James Morris 2017-07-19 9:19 ` James Morris 2017-07-19 23:56 ` Paul Moore 2017-07-19 23:56 ` Paul Moore 2017-07-18 22:25 ` [PATCH v3 03/15] apparmor: Refactor to remove bprm_secureexec hook Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 0:00 ` John Johansen 2017-07-19 0:00 ` John Johansen 2017-07-19 9:21 ` James Morris 2017-07-19 9:21 ` James Morris 2017-07-18 22:25 ` [PATCH v3 04/15] selinux: " Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-20 0:03 ` Paul Moore 2017-07-20 0:03 ` Paul Moore 2017-07-20 0:19 ` Paul Moore 2017-07-20 0:19 ` Paul Moore 2017-07-20 1:37 ` Kees Cook 2017-07-20 1:37 ` Kees Cook 2017-07-20 13:42 ` Paul Moore 2017-07-20 13:42 ` Paul Moore 2017-07-20 17:06 ` Kees Cook 2017-07-20 17:06 ` Kees Cook 2017-07-20 20:42 ` Paul Moore 2017-07-20 20:42 ` Paul Moore 2017-07-21 15:40 ` Paul Moore 2017-07-21 15:40 ` Paul Moore 2017-07-21 17:37 ` Kees Cook 2017-07-21 17:37 ` Kees Cook 2017-07-21 19:16 ` Paul Moore 2017-07-21 19:16 ` Paul Moore 2017-07-18 22:25 ` [PATCH v3 05/15] smack: " Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-26 3:58 ` Kees Cook 2017-07-26 3:58 ` Kees Cook 2017-07-26 15:24 ` Casey Schaufler 2017-07-26 15:24 ` Casey Schaufler 2017-07-18 22:25 ` [PATCH v3 06/15] commoncap: " Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 1:10 ` Andy Lutomirski 2017-07-19 1:10 ` Andy Lutomirski 2017-07-19 4:41 ` Kees Cook 2017-07-19 4:41 ` Kees Cook 2017-07-20 4:53 ` Andy Lutomirski 2017-07-20 4:53 ` Andy Lutomirski 2017-07-31 22:43 ` Kees Cook 2017-07-31 22:43 ` Kees Cook 2017-08-01 13:12 ` Andy Lutomirski 2017-08-01 13:12 ` Andy Lutomirski 2017-07-19 9:26 ` James Morris 2017-07-19 9:26 ` James Morris 2017-07-18 22:25 ` [PATCH v3 07/15] commoncap: Move cap_elevated calculation into bprm_set_creds Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 1:52 ` Andy Lutomirski 2017-07-19 1:52 ` Andy Lutomirski 2017-07-19 9:28 ` James Morris 2017-07-19 9:28 ` James Morris 2017-07-18 22:25 ` [PATCH v3 08/15] LSM: drop bprm_secureexec hook Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 0:02 ` John Johansen 2017-07-19 0:02 ` John Johansen 2017-07-19 9:29 ` James Morris 2017-07-19 9:29 ` James Morris 2017-07-18 22:25 ` [PATCH v3 09/15] exec: Correct comments about "point of no return" Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 0:45 ` Eric W. Biederman 2017-07-19 0:45 ` Eric W. Biederman 2017-07-18 22:25 ` [PATCH v3 10/15] exec: Use secureexec for setting dumpability Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-26 3:59 ` Kees Cook [this message] 2017-07-26 3:59 ` Kees Cook 2017-07-18 22:25 ` [PATCH v3 11/15] exec: Use secureexec for clearing pdeath_signal Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-18 22:25 ` [PATCH v3 12/15] smack: Remove redundant pdeath_signal clearing Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-18 22:25 ` [PATCH v3 13/15] exec: Consolidate dumpability logic Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-18 22:25 ` [PATCH v3 14/15] exec: Use sane stack rlimit under secureexec Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-19 9:42 ` James Morris 2017-07-19 9:42 ` James Morris 2017-07-18 22:25 ` [PATCH v3 15/15] exec: Consolidate pdeath_signal clearing Kees Cook 2017-07-18 22:25 ` Kees Cook 2017-07-18 23:03 ` [PATCH v3 00/15] exec: Use sane stack rlimit under secureexec Linus Torvalds 2017-07-18 23:03 ` Linus Torvalds 2017-07-19 3:22 ` Serge E. Hallyn 2017-07-19 3:22 ` Serge E. Hallyn 2017-07-19 5:23 ` Kees Cook 2017-07-19 5:23 ` Kees Cook
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