[libdvbpsi-devel] TOT decode - bug

[Angelo Schiavone]

Hi,
NIT and BAT table already start at the right location
but the problem with them is (as pointed out in the patch)
with the calculation of p_end which needs a +2 otherwise
decoder may miss last descriptor in the loop.
attached the patch against last commit.
thanks






>From 4dbf8cf04b0e1f38743f08c0d14416fe77e7cd05 Mon Sep 17 00:00:00 2001
From: Angelo Schiavone <angelo.schiavone at screen.it>
Date: Thu, 24 Jan 2013 08:52:11 +0100
Subject: [PATCH] fixes NIT and BAT descriptors loop decoding, p_end is now
 correctly calculated

---
 src/tables/bat.c |    2 +-
 src/tables/nit.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/tables/bat.c b/src/tables/bat.c
index 9811795..efda516 100644
--- a/src/tables/bat.c
+++ b/src/tables/bat.c
@@ -489,7 +489,7 @@ void dvbpsi_bat_sections_decode(dvbpsi_bat_t* p_bat,
             p_byte += 2 + i_length;
         }

-        p_end = p_byte + (((uint16_t)(p_byte[0] & 0x0f) << 8)
+        p_end = 2 + p_byte + (((uint16_t)(p_byte[0] & 0x0f) << 8)
                           | p_byte[1]);
         if (p_end > p_section->p_payload_end)
             p_end = p_section->p_payload_end;
diff --git a/src/tables/nit.c b/src/tables/nit.c
index 1532e3d..dce830e 100644
--- a/src/tables/nit.c
+++ b/src/tables/nit.c
@@ -474,7 +474,7 @@ void dvbpsi_nit_sections_decode(dvbpsi_nit_t* p_nit,
         }

         /* Transport stream loop length */
-        p_end = p_byte + (((uint16_t)(p_byte[0] & 0x0f) << 8)
+        p_end = 2 + p_byte + (((uint16_t)(p_byte[0] & 0x0f) << 8)
                           | p_byte[1]);
         if (p_end > p_section->p_payload_end)
             p_end = p_section->p_payload_end;
-- 
1.7.9.5



2013/1/23 Jean-Paul Saman <jpsaman at videolan.org>

> Oops pressed send too soon.
>
>
> On Wed, Jan 23, 2013 at 8:22 PM, Jean-Paul Saman <jpsaman at videolan.org>wrote:
>
>> Angelo,
>>
>> On Wed, Jan 23, 2013 at 3:16 PM, Angelo Schiavone <
>> angelo.schiavone at gmail.com> wrote:
>>
>>> here is the git patch.
>>
>>
>> In the end I did not use your patches to fix the issues. I just pushed
>> changes that should fix all
>> the bugs you noticed. It does need some wider testing so please try it ;)
>>
>> If you find any issue, then please report them again.
>>
>> Some feedback on your patch:
>> - both NIT and BAT table already start at the right location since p_byte
>> is defined as:
>>
>
> p_byte = p_section->p_playload_start + 2;
>
>   - the other change in BAT table was correctly spotted
>   - you were right about the CAT table
>   - the CRC32 validation for TOT table has been solved in another way.
>
> Kind regards,
> Jean-Paul Saman
>
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