[dpdk-stable] [PATCH v2] lpm: fix buffer overflow

[Vladimir Medvedkin <vladimir.medvedkin@intel.com>]

This patch fixes buffer overflow reported by ASAN,
please reference https://bugs.dpdk.org/show_bug.cgi?id=819

The rte_lpm6 keeps routing information for control plane purpose
inside the rte_hash table which uses rte_jhash() as a hash function.
From the rte_jhash() documentation: If input key is not aligned to
four byte boundaries or a multiple of four bytes in length,
the memory region just after may be read (but not used in the
computation).
rte_lpm6 uses 17 bytes keys consisting of IPv6 address (16 bytes) +
depth (1 byte).

This patch increases the size of the depth field up to uint32_t
and sets the alignment to 4 bytes.

Bugzilla ID: 819
Fixes: 86b3b21952a8 ("lpm6: store rules in hash table")
Cc: alex@therouter.net
Cc: stable@dpdk.org

Signed-off-by: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
---
 lib/lpm/rte_lpm6.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/lpm/rte_lpm6.c b/lib/lpm/rte_lpm6.c
index 37baabb..73768fc 100644
--- a/lib/lpm/rte_lpm6.c
+++ b/lib/lpm/rte_lpm6.c
@@ -80,7 +80,7 @@ struct rte_lpm6_rule {
 /** Rules tbl entry key. */
 struct rte_lpm6_rule_key {
 	uint8_t ip[RTE_LPM6_IPV6_ADDR_SIZE]; /**< Rule IP address. */
-	uint8_t depth; /**< Rule depth. */
+	uint32_t depth; /**< Rule depth. */
 };
 
 /* Header of tbl8 */
@@ -259,6 +259,8 @@ rte_lpm6_create(const char *name, int socket_id,
 	lpm_list = RTE_TAILQ_CAST(rte_lpm6_tailq.head, rte_lpm6_list);
 
 	RTE_BUILD_BUG_ON(sizeof(struct rte_lpm6_tbl_entry) != sizeof(uint32_t));
+	RTE_BUILD_BUG_ON(sizeof(struct rte_lpm6_rule_key) %
+		sizeof(uint32_t) != 0);
 
 	/* Check user arguments. */
 	if ((name == NULL) || (socket_id < -1) || (config == NULL) ||
-- 
2.7.4