MDEV-19669 - fix matching CIDR address for proxy protocol.

vaintroub · vaintroub · commit 584ffa02f1be · 2019-11-27T20:50:06.000+01:00
Prior to this fix, when matching addresses using mask,
extra bits could be used for  comparison, e.g to
match with "a.b.c.d/24" , 27 bits were compared rather than 24.

The patch fixes the calculation.
diff --git a/sql/proxy_protocol.cc b/sql/proxy_protocol.cc
@@ -470,7 +470,7 @@ static int compare_bits(const void *s1, const void *s2, int bit_count)
   int byte_count= bit_count / 8;
   if (byte_count && (result= memcmp(s1, s2, byte_count)))
     return result;
-  int rem= byte_count % 8;
+  int rem= bit_count % 8;
   if (rem)
   {
     // compare remaining bits i.e partial bytes.

Original file line number	Diff line number	Diff line change
`@@ -470,7 +470,7 @@ static int compare_bits(const void s1, const void s2, int bit_count)`
`470`	`470`	`int byte_count= bit_count / 8;`
`471`	`471`	`if (byte_count && (result= memcmp(s1, s2, byte_count)))`
`472`	`472`	`return result;`
`473`		`- int rem= byte_count % 8;`
	`473`	`+ int rem= bit_count % 8;`
`474`	`474`	`if (rem)`
`475`	`475`	`{`
`476`	`476`	`// compare remaining bits i.e partial bytes.`