lib/table: fix table autotest ut crashes in ipv6

  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.

Fixes: d89a5bce1d ("lpm6: extend next hop field")
Cc: stable@dpdk.org

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

On Tue, Jul 2, 2019 at 1:22 PM Jananee Parthasarathy <
jananeex.m.parthasarathy@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@dpdk.org
>
> Signed-off-by: Jananee Parthasarathy <jananeex.m.parthasarathy@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@redhat.com>
  

From: David Marchand [mailto:david.marchand@redhat.com]
Sent: Tuesday, July 2, 2019 12:46 PM
To: Parthasarathy, JananeeX M <jananeex.m.parthasarathy@intel.com>
Cc: dev <dev@dpdk.org>; Pattan, Reshma <reshma.pattan@intel.com>; Dumitrescu, Cristian <cristian.dumitrescu@intel.com>; Singh, Jasvinder <jasvinder.singh@intel.com>; dpdk stable <stable@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@intel.com<mailto:jananeex.m.parthasarathy@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@dpdk.org<mailto:stable@dpdk.org>

Signed-off-by: Jananee Parthasarathy <jananeex.m.parthasarathy@intel.com<mailto:jananeex.m.parthasarathy@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@redhat.com<mailto:david.marchand@redhat.com>>

--
David Marchand

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

02/07/2019 13:50, Dumitrescu, Cristian:
> From: David Marchand [mailto:david.marchand@redhat.com]
> On Tue, Jul 2, 2019 at 1:22 PM Jananee Parthasarathy <jananeex.m.parthasarathy@intel.com<mailto:jananeex.m.parthasarathy@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@dpdk.org<mailto:stable@dpdk.org>
> 
> Signed-off-by: Jananee Parthasarathy <jananeex.m.parthasarathy@intel.com<mailto:jananeex.m.parthasarathy@intel.com>>
[...]
> It fixes the segfault I saw, leaving the ack to the maintainer.
> Tested-by: David Marchand <david.marchand@redhat.com<mailto:david.marchand@redhat.com>>
> 
> Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

Applied, thanks