From df666f70534ef225b97899f997b4077aeb285972 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Thu, 6 Jul 2023 15:57:18 +0200
Subject: [PATCH] libsepol: check for overflow in put_entry()
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put_entry() is used during writing binary policies.  Avoid short writes
due to an overflow.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
---
 libsepol/src/services.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libsepol/src/services.c b/libsepol/src/services.c
index 72772dbd29..6bddc287e1 100644
--- a/libsepol/src/services.c
+++ b/libsepol/src/services.c
@@ -1711,7 +1711,10 @@ int next_entry(void *buf, struct policy_file *fp, size_t bytes)
 size_t put_entry(const void *ptr, size_t size, size_t n,
 			struct policy_file *fp)
 {
-	size_t bytes = size * n;
+	size_t bytes;
+
+	if (__builtin_mul_overflow(size, n, &bytes))
+		return 0;
 
 	switch (fp->type) {
 	case PF_USE_STDIO: