[PATCH 2/2] Smack: prevent underflow in smk_set_cipso()
From: Dan Carpenter
Date: Thu Jul 23 2020 - 11:25:56 EST
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 <dan.carpenter@xxxxxxxxxx>
---
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 81c6ceeaa4f9..7675305511ef 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -884,7 +884,7 @@ 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;
--
2.27.0