Re: [Qemu-devel] [PATCH] eepro100: prevent an infinite loop over same command block

[P J P <ppandit@redhat.com>]

+-- On Fri, 16 Oct 2015, Paolo Bonzini wrote --+
| > +        if (s->tx.link == s->cu_offset)
| > +            break;
| 
| Please update the patch to conform to QEMU's coding standards; braces
| are required even around single-statement blocks.

  Done. Please see an updated patch below.

===
>From bbf7b8914a984b09242e1cafc258bd71cecc47c8 Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Fri, 16 Oct 2015 22:43:29 +0530
Subject: eepro100: prevent an infinite loop over same command block

action_command() routine executes a chain of commands located
in the Command Block List(CBL). Each Command Block(CB) has a
link to the next CB in the list, given by 's->tx.link'.
This is used in conjunction with the base address 's->cu_base'.

An infinite loop unfolds if the 'link' to the next CB is
same as the previous one, the loop ends up executing the same
command over and over again.

Reported-by: Qinghao Tang <luodalongde@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/net/eepro100.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/net/eepro100.c b/hw/net/eepro100.c
index 60333b7..0e4ad4e 100644
--- a/hw/net/eepro100.c
+++ b/hw/net/eepro100.c
@@ -863,6 +863,9 @@ static void action_command(EEPRO100State *s)
         uint16_t ok_status = STATUS_OK;
         s->cb_address = s->cu_base + s->cu_offset;
         read_cb(s);
+        if (s->tx.link == s->cu_offset) {
+            break;
+        }
         bit_el = ((s->tx.command & COMMAND_EL) != 0);
         bit_s = ((s->tx.command & COMMAND_S) != 0);
         bit_i = ((s->tx.command & COMMAND_I) != 0);
-- 
2.4.3
===


Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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