[dpdk-dev] [PATCH] lib/table: fix table autotest ut crashes in ipv6

[Dumitrescu, Cristian]

From: David Marchand [mailto:david.marchand at redhat.com]
Sent: Tuesday, July 2, 2019 12:46 PM
To: Parthasarathy, JananeeX M <jananeex.m.parthasarathy at intel.com>
Cc: dev <dev at dpdk.org>; Pattan, Reshma <reshma.pattan at intel.com>; Dumitrescu, Cristian <cristian.dumitrescu at intel.com>; Singh, Jasvinder <jasvinder.singh at intel.com>; dpdk stable <stable at dpdk.org>
Subject: Re: [PATCH] lib/table: fix table autotest ut crashes in ipv6



On Tue, Jul 2, 2019 at 1:22 PM Jananee Parthasarathy <jananeex.m.parthasarathy at intel.com<mailto:jananeex.m.parthasarathy at intel.com>> wrote:
Unit test table_autotest results in segmentation fault.
Crash occurs in test_table_lpm_ipv6_combined().

Variable 'nht_pos0' used as array subscript is not initialized
in rte_table_lpm_ipv6_entry_add(). It will not be assigned,
if a rule does not exist.

In such case a junk number or invalid array index might result in
segmentation fault due to array out of bounds when
lpm->nht_users is used with such invalid array index.

Fix is to initialize the variables used for array subscript.

Bugzilla ID: 285

Fixes: d89a5bce1d ("lpm6: extend next hop field")
Cc: stable at dpdk.org<mailto:stable at dpdk.org>

Signed-off-by: Jananee Parthasarathy <jananeex.m.parthasarathy at intel.com<mailto:jananeex.m.parthasarathy at intel.com>>
---
 lib/librte_table/rte_table_lpm_ipv6.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/librte_table/rte_table_lpm_ipv6.c b/lib/librte_table/rte_table_lpm_ipv6.c
index a55f808a4..4e068d79b 100644
--- a/lib/librte_table/rte_table_lpm_ipv6.c
+++ b/lib/librte_table/rte_table_lpm_ipv6.c
@@ -182,7 +182,7 @@ rte_table_lpm_ipv6_entry_add(
        struct rte_table_lpm_ipv6 *lpm = table;
        struct rte_table_lpm_ipv6_key *ip_prefix =
                key;
-       uint32_t nht_pos, nht_pos0, nht_pos0_valid;
+       uint32_t nht_pos = 0, nht_pos0 = 0, nht_pos0_valid = 0;

nht_pos_valid is unconditionnally set, no need to initialize.
Just noticed that nht_pos is not initialised to 0 in ipv4 code.

It fixes the segfault I saw, leaving the ack to the maintainer.
Tested-by: David Marchand <david.marchand at redhat.com<mailto:david.marchand at redhat.com>>

--
David Marchand

Acked-by: Cristian Dumitrescu <cristian.dumitrescu at intel.com>