4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Kees Cook <[email protected]> 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 <[email protected]> Fixes: e37fdb785a5f ("exec: Use secureexec for setting dumpability") Signed-off-by: Kees Cook <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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);
