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

From	Kees Cook <keescook@chromium.org>
Newsgroups	linux.kernel
Subject	[PATCH v5 13/15] exec: Consolidate dumpability logic
Date	2017-08-01 21:20 +0200
Message-ID	<u9KRY-82o-15@gated-at.bofh.it> (permalink)
References	<u9KRX-82o-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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@chromium.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
---
 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

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[PATCH v5 13/15] exec: Consolidate dumpability logic Kees Cook <keescook@chromium.org> - 2017-08-01 21:20 +0200

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