[Spice-devel] [PATCH] quic: Fix "OVERRUN" caught by coverity

[Fabiano Fidêncio]

Pre-incrementing the variable used as the array's index can make such
index exceed the array's bounds. Although that (...)->rgb_state.melcstate
has to be less than MELCSTATE to get inside the branch, it may be up to
MELCSTATE after the pre-incrementing, which would result in an access to
a position that is out bounds of the array sized MELCSTATE.
---
 common/quic.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/common/quic.c b/common/quic.c
index c10e3c4..ea6bd71 100644
--- a/common/quic.c
+++ b/common/quic.c
@@ -579,7 +579,7 @@ static void encode_run(Encoder *encoder, unsigned int runlen) //todo: try use en
         hits++;
         runlen -= encoder->rgb_state.melcorder;
         if (encoder->rgb_state.melcstate < MELCSTATES) {
-            encoder->rgb_state.melclen = J[++encoder->rgb_state.melcstate];
+            encoder->rgb_state.melclen = J[encoder->rgb_state.melcstate++];
             encoder->rgb_state.melcorder = (1L << encoder->rgb_state.melclen);
         }
     }
@@ -611,7 +611,7 @@ static void encode_channel_run(Encoder *encoder, Channel *channel, unsigned int
         hits++;
         runlen -= channel->state.melcorder;
         if (channel->state.melcstate < MELCSTATES) {
-            channel->state.melclen = J[++channel->state.melcstate];
+            channel->state.melclen = J[channel->state.melcstate++];
             channel->state.melcorder = (1L << channel->state.melclen);
         }
     }
@@ -648,7 +648,7 @@ static int decode_run(Encoder *encoder)
             runlen += encoder->rgb_state.melcorder;
 
             if (encoder->rgb_state.melcstate < MELCSTATES) {
-                encoder->rgb_state.melclen = J[++encoder->rgb_state.melcstate];
+                encoder->rgb_state.melclen = J[encoder->rgb_state.melcstate++];
                 encoder->rgb_state.melcorder = (1U << encoder->rgb_state.melclen);
             }
         }
@@ -689,7 +689,7 @@ static int decode_channel_run(Encoder *encoder, Channel *channel)
             runlen += channel->state.melcorder;
 
             if (channel->state.melcstate < MELCSTATES) {
-                channel->state.melclen = J[++channel->state.melcstate];
+                channel->state.melclen = J[channel->state.melcstate++];
                 channel->state.melcorder = (1U << channel->state.melclen);
             }
         }
-- 
1.9.3