This is a note to let you know that I've just added the patch titled

exec: Weaken dumpability for secureexec

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: exec-weaken-dumpability-for-secureexec.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From e816c201aed5232171f8eb80b5d46ae6516683b9 Mon Sep 17 00:00:00 2001

From: Kees Cook keescook@chromium.org Date: Tue, 2 Jan 2018 15:21:33 -0800 Subject: exec: Weaken dumpability for secureexec

From: Kees Cook keescook@chromium.org

commit e816c201aed5232171f8eb80b5d46ae6516683b9 upstream.

This is a logical revert of commit e37fdb785a5f ("exec: Use secureexec for setting dumpability")

This weakens dumpability back to checking only for uid/gid changes in current (which is useless), but userspace depends on dumpability not being tied to secureexec.

https://bugzilla.redhat.com/show_bug.cgi?id=1528633

Reported-by: Tom Horsley horsley1953@gmail.com Fixes: e37fdb785a5f ("exec: Use secureexec for setting dumpability") Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- fs/exec.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/fs/exec.c +++ b/fs/exec.c @@ -1350,9 +1350,14 @@ void setup_new_exec(struct linux_binprm

current->sas_ss_sp = current->sas_ss_size = 0;

- /* Figure out dumpability. */ + /* + * Figure out dumpability. Note that this checking only of current + * is wrong, but userspace depends on it. This should be testing + * bprm->secureexec instead. + */ if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP || - bprm->secureexec) + !(uid_eq(current_euid(), current_uid()) && + gid_eq(current_egid(), current_gid()))) set_dumpable(current->mm, suid_dumpable); else set_dumpable(current->mm, SUID_DUMP_USER);

Patches currently in stable-queue which might be from keescook@chromium.org are

queue-4.14/exec-weaken-dumpability-for-secureexec.patch