From 3ad49d37cf5759c3b8b68d02e3563f633d9c1aee Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@linaro.org>
Date: Thu, 6 Jul 2023 08:52:39 +0300
Subject: [PATCH] smackfs: Prevent underflow in smk_set_cipso()
There is a upper bound to "catlen" but no lower bound to prevent
negatives. I don't see that this necessarily causes a problem but we
may as well be safe.
Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
security/smack/smackfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 2b79c30d4bb6b..e22aad7604e8a 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -896,7 +896,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
}
ret = sscanf(rule, "%d", &catlen);
- if (ret != 1 || catlen > SMACK_CIPSO_MAXCATNUM)
+ if (ret != 1 || catlen < 0 || catlen > SMACK_CIPSO_MAXCATNUM)
goto out;
if (format == SMK_FIXED24_FMT &&
--
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