net: pktgen: fix mpls maximum labels list parsing

[ Upstream commit 2b15a0693f70d1e8119743ee89edbfb1271b3ea8 ]

Fix mpls maximum labels list parsing up to MAX_MPLS_LABELS entries (instead
of up to MAX_MPLS_LABELS - 1).

Addresses the following:

	$ echo "mpls 00000f00,00000f01,00000f02,00000f03,00000f04,00000f05,00000f06,00000f07,00000f08,00000f09,00000f0a,00000f0b,00000f0c,00000f0d,00000f0e,00000f0f" > /proc/net/pktgen/lo\@0
	-bash: echo: write error: Argument list too long

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 82b6a2c3c141f29790c40c34d0f4361faf2b1f2e..6ea34c95179f40d001f138ca225201ee75ba0ec6 100644 (file)
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -898,6 +898,10 @@ static ssize_t get_labels(const char __user *buffer, struct pktgen_dev *pkt_dev)
        pkt_dev->nr_labels = 0;
        do {
                __u32 tmp;
+
+               if (n >= MAX_MPLS_LABELS)
+                       return -E2BIG;
+
                len = hex32_arg(&buffer[i], 8, &tmp);
                if (len <= 0)
                        return len;
@@ -909,8 +913,6 @@ static ssize_t get_labels(const char __user *buffer, struct pktgen_dev *pkt_dev)
                        return -EFAULT;
                i++;
                n++;
-               if (n >= MAX_MPLS_LABELS)
-                       return -E2BIG;
        } while (c == ',');
 
        pkt_dev->nr_labels = n;