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From: "Herongguang (Stephen)" <herongguang.he@huawei.com>
To: qemu-devel@nongnu.org, kraxel@redhat.com, pbonzini@redhat.com,
	herongguang.he@huawei.com, weidong.huang@huawei.com,
	"peter.huangpeng@huawei.com >> Huangpeng (Peter)"
	<peter.huangpeng@huawei.com>
Subject: [Qemu-devel]  [PATCH] vnc-enc-tight: fix off-by-one bug
Date: Tue, 12 Jul 2016 17:31:23 +0800	[thread overview]
Message-ID: <5784B8EB.7010008@huawei.com> (raw)

In tight_encode_indexed_rect32, buf(or src)’s size is count. In for loop,
the logic is supposed to be that i is an index into src, i should be
incremented when incrementing src.

This is broken when src is incremented but i is not before while loop,
resulting in off-by-one bug in while loop.

Signed-off-by: He Rongguang <herongguang.he@huawei.com>
---
  ui/vnc-enc-tight.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ui/vnc-enc-tight.c b/ui/vnc-enc-tight.c
index e5cba0e..678c5df 100644
--- a/ui/vnc-enc-tight.c
+++ b/ui/vnc-enc-tight.c
@@ -461,9 +461,10 @@ static int tight_fill_palette(VncState *vs, int x, int y,
                                                                          \
          src = (uint##bpp##_t *) buf;                                    \
                                                                          \
-        for (i = 0; i < count; i++) {                                   \
+        for (i = 0; i < count; ) {                                      \
                                                                          \
              rgb = *src++;                                               \
+            i++;                                                        \
              rep = 0;                                                    \
              while (i < count && *src == rgb) {                          \
                  rep++, src++, i++;                                      \
-- 
1.8.3.4

             reply	other threads:[~2016-07-12  9:34 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-12  9:31 Herongguang (Stephen) [this message]
2016-07-15 10:10 ` [Qemu-devel] [PATCH] vnc-enc-tight: fix off-by-one bug Gerd Hoffmann

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