Feature bits that are invalid should not be accepted by the kernel,
only the lower 4 bits may be configured, but not the remaining ones.
Even from these 4, 2 of them are unused.
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
---
include/uapi/linux/rtnetlink.h | 11 +++++++----
net/ipv4/fib_semantics.c | 2 ++
net/ipv6/route.c | 2 ++
3 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index 0d3d3cc..7020247 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -418,10 +418,13 @@ enum {
#define RTAX_MAX (__RTAX_MAX - 1)
-#define RTAX_FEATURE_ECN 0x00000001
-#define RTAX_FEATURE_SACK 0x00000002
-#define RTAX_FEATURE_TIMESTAMP 0x00000004
-#define RTAX_FEATURE_ALLFRAG 0x00000008
+#define RTAX_FEATURE_ECN (1 << 0)
+#define RTAX_FEATURE_SACK (1 << 1)
+#define RTAX_FEATURE_TIMESTAMP (1 << 2)
+#define RTAX_FEATURE_ALLFRAG (1 << 3)
+
+#define RTAX_FEATURE_MASK (RTAX_FEATURE_ECN | RTAX_FEATURE_SACK | \
+ RTAX_FEATURE_TIMESTAMP | RTAX_FEATURE_ALLFRAG)
struct rta_session {
__u8 proto;
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 88afbae..115a08e 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -908,6 +908,8 @@ 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_FEATURES && (val & ~RTAX_FEATURE_MASK))
+ return -EINVAL;
fi->fib_metrics[type - 1] = val;
}
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 0261b72..8771530 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1728,6 +1728,8 @@ static int ip6_convert_metrics(struct mx6_config *mxc,
} else {
val = nla_get_u32(nla);
}
+ if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
+ goto err;
mp[type - 1] = val;
__set_bit(type - 1, mxc->mx_valid);
--
1.9.3
--
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