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[2/2] Smack: prevent underflow in smk_set_cipso()

Message ID 20200723152305.GB302005@mwanda (mailing list archive)
State New, archived
Headers show
Series [1/2] Smack: fix another vsscanf out of bounds | expand

Commit Message

Dan Carpenter July 23, 2020, 3:23 p.m. UTC 
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@oracle.com>
---
 security/smack/smackfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

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;