From: Kees Cook Date: Tue, 18 Jul 2017 22:25:31 +0000 (-0700) Subject: exec: Use secureexec for setting dumpability X-Git-Tag: v4.14-rc1~98^2~5 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e37fdb785a5f95ecadf43b773c97f676500ac7b8;p=platform%2Fkernel%2Flinux-exynos.git exec: Use secureexec for setting dumpability 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 Signed-off-by: Kees Cook Acked-by: Serge Hallyn Reviewed-by: James Morris --- diff --git a/fs/exec.c b/fs/exec.c index eca0cb5..3536437 100644 --- 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);