[PATCH v5 13/15] exec: Consolidate dumpability logic

From: Kees Cook
Date: Tue Aug 01 2017 - 15:17:18 EST


Since it's already valid to set dumpability in the early part of
setup_new_exec(), we can consolidate the logic into a single place.
The BINPRM_FLAGS_ENFORCE_NONDUMP is set during would_dump() calls
before setup_new_exec(), so its test is safe to move as well.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Serge Hallyn <serge@xxxxxxxxxx>
Reviewed-by: James Morris <james.l.morris@xxxxxxxxxx>
---
fs/exec.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 7a9288551d62..3006c1c24304 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1354,10 +1354,12 @@ void setup_new_exec(struct linux_binprm * bprm)

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

- if (!bprm->secureexec)
- set_dumpable(current->mm, SUID_DUMP_USER);
- else
+ /* Figure out dumpability. */
+ if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP ||
+ bprm->secureexec)
set_dumpable(current->mm, suid_dumpable);
+ else
+ set_dumpable(current->mm, SUID_DUMP_USER);

arch_setup_new_exec();
perf_event_exec();
@@ -1371,9 +1373,6 @@ void setup_new_exec(struct linux_binprm * bprm)

if (bprm->secureexec) {
current->pdeath_signal = 0;
- } else {
- if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
- set_dumpable(current->mm, suid_dumpable);
}

/* An exec changes our domain. We are no longer part of the thread
--
2.7.4