jenkins-bot has submitted this change and it was merged.
Change subject: Docs for gerrit 47419
......................................................................
Docs for gerrit 47419
Change-Id: I021b7250418e60397127e1778107ee3da77ffb18
---
M includes/objectcache/MemcachedClient.php
1 file changed, 25 insertions(+), 1 deletion(-)
Approvals:
Aaron Schulz: Looks good to me, approved
jenkins-bot: Verified
diff --git a/includes/objectcache/MemcachedClient.php
b/includes/objectcache/MemcachedClient.php
index 441c02b..f8ce0d0 100644
--- a/includes/objectcache/MemcachedClient.php
+++ b/includes/objectcache/MemcachedClient.php
@@ -911,10 +911,21 @@
while ( 1 ) {
$decl = $this->_fgets( $sock );
+
if( $decl === false ) {
+ /*
+ * If nothing can be read, something is wrong
because we know exactly when
+ * to stop reading (right after "END") and we
return right after that.
+ */
return false;
} elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)
(\d+)$/', $decl, $match ) ) {
-
+ /*
+ * Read all data returned. This can be either
one or multiple values.
+ * Save all that data (in an array) to be
processed later: we'll first
+ * want to continue reading until "END" before
doing anything else,
+ * to make sure that we don't leave our client
in a state where it's
+ * output is not yet fully read.
+ */
$results[] = array(
$match[1], // rkey
$match[2], // flags
@@ -927,6 +938,10 @@
return false;
}
+ /**
+ * All data has been read, time to process the
data and build
+ * meaningful return values.
+ */
foreach ( $results as $vars ) {
list( $rkey, $flags, $len, $casToken,
$data ) = $vars;
@@ -942,6 +957,15 @@
$ret[$rkey] = gzuncompress(
$ret[$rkey] );
}
+ /*
+ * This unserialize is the exact reason
that we only want to
+ * process data after having read until
"END" (instead of doing
+ * this right away): "unserialize" can
trigger outside code:
+ * in the event that $ret[$rkey] is a
serialized object,
+ * unserializing it will trigger
__wakeup() if present. If that
+ * function attempted to read from
memcached (while we did not
+ * yet read "END"), these 2 calls would
collide.
+ */
if ( $flags & self::SERIALIZED ) {
$ret[$rkey] = unserialize(
$ret[$rkey] );
}
--
To view, visit https://gerrit.wikimedia.org/r/52632
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: merged
Gerrit-Change-Id: I021b7250418e60397127e1778107ee3da77ffb18
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: master
Gerrit-Owner: Matthias Mullie <[email protected]>
Gerrit-Reviewer: Aaron Schulz <[email protected]>
Gerrit-Reviewer: jenkins-bot
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