From adef6d2d512d140ac2b02776a3f266f60b8827d2 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 23 Jul 2020 18:23:05 +0300 Subject: [PATCH] Smack: prevent underflow in smk_set_cipso() [ Upstream commit 42a2df3e829f3c5562090391b33714b2e2e5ad4a ] We have an upper bound on "maplevel" but forgot to check for negative values. Fixes: e114e473771c ("Smack: Simplified Mandatory Access Control Kernel") Signed-off-by: Dan Carpenter Signed-off-by: Casey Schaufler Signed-off-by: Sasha Levin --- 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 981f582539ac..accd3846f1e3 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -912,7 +912,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf, } ret = sscanf(rule, "%d", &maplevel); - if (ret != 1 || maplevel > SMACK_CIPSO_MAXLEVEL) + if (ret != 1 || maplevel < 0 || maplevel > SMACK_CIPSO_MAXLEVEL) goto out; rule += SMK_DIGITLEN;