On 07/14/2014 11:14 AM, Fabiano Fidêncio wrote:
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.
Hi,
I think it's safer to change the condition (MELCSTATES-1) than
changing the pre/post increment.
melcstate and melclen (and melcorder) should be kept in sync.
Thanks,
Uri
---
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);
}
}
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