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net/route: enforce hoplimit max value 

Currently, when creating or updating a route, no check is performed
in both ipv4 and ipv6 code to the hoplimit value.

The caller can i.e. set hoplimit to 256, and when such route will
 be used, packets will be sent with hoplimit/ttl equal to 0.

This commit adds checks for the RTAX_HOPLIMIT value, in both ipv4
ipv6 route code, substituting any value greater than 255 with 255.

This is consistent with what is currently done for ADVMSS and MTU
in the ipv4 code.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2016-05-13 18:33:41 +02:00 committed by David S. Miller
parent 31b0b385f6
commit 626abd59e5
2 changed files with 4 additions and 0 deletions
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2
net/ipv4/fib_semantics.c
View File

@ -975,6 +975,8 @@ fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
val = 65535 - 40;
if (type == RTAX_MTU && val > 65535 - 15)
val = 65535 - 15;
if (type == RTAX_HOPLIMIT && val > 255)
val = 255;
if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
return -EINVAL;
fi->fib_metrics[type - 1] = val;

2
net/ipv6/route.c
View File

@ -1750,6 +1750,8 @@ static int ip6_convert_metrics(struct mx6_config *mxc,
} else {
val = nla_get_u32(nla);
}
if (type == RTAX_HOPLIMIT && val > 255)
val = 255;
if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
goto err;