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Blame SOURCES/0072-Ticket-49296-Fix-race-condition-in-connection-code-w.patch

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From dd12327d1523f3ff9d6ae8b44b640fb9d0d2d53b Mon Sep 17 00:00:00 2001
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From: Mark Reynolds <mreynolds@redhat.com>
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Date: Mon, 19 Feb 2018 10:44:36 -0500
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Subject: [PATCH] Ticket 49296 - Fix race condition in connection code with 
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 anonymous limits
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Bug Description:  When a connection first comes in we set the anonymous
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                  resource limits (if set) before we do anything else.  The
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                  way we check if the connection is "new" was flawed.  It
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                  assumed the connection was new if no operations were
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                  completed yet, but there was a small window between sending
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                  the result and setting that the operation completed in the
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                  connection struct.
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                  So on a connection that binds and then does a search, when
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                  the server sends the bind result the client sends the search,
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                  but the search op/activity can be picked up before we set
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                  c_opscompleted.  This opens a window where the code thinks
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                  the search op is the first op(new connection), and it incorrectly
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                  sets the anonymous limits for the bind dn.
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Fix description:  Do not use c_opscompleted to determine if a connection is new,
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                  instead use a new flag to set the connection "initialized",
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                  which prevents the race condition.
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https://pagure.io/389-ds-base/issue/49296
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Reviewed by: firstyear(Thanks!)
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(cherry picked from commit 0d5214d08e6b5b39fb9d5ef5cf3d8834574954f1)
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---
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 ldap/servers/slapd/connection.c | 12 +++++++++++-
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 ldap/servers/slapd/slap.h       |  7 +++----
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 2 files changed, 14 insertions(+), 5 deletions(-)
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diff --git a/ldap/servers/slapd/connection.c b/ldap/servers/slapd/connection.c
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index 5d2b64ed2..5ca32a333 100644
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--- a/ldap/servers/slapd/connection.c
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+++ b/ldap/servers/slapd/connection.c
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@@ -217,6 +217,7 @@ connection_cleanup(Connection *conn)
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     conn->c_connid = 0;
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     conn->c_opsinitiated = 0;
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     conn->c_opscompleted = 0;
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+    conn->c_anonlimits_set = 0;
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     conn->c_threadnumber = 0;
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     conn->c_refcnt = 0;
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     conn->c_idlesince = 0;
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@@ -1549,7 +1550,9 @@ connection_threadmain()
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                     g_decr_active_threadcnt();
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                     return;
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                 }
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-                if (pb_conn->c_opscompleted == 0) {
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+
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+                PR_EnterMonitor(pb_conn->c_mutex);
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+                if (pb_conn->c_anonlimits_set == 0) {
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                     /*
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                      * We have a new connection, set the anonymous reslimit idletimeout
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                      * if applicable.
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@@ -1568,7 +1571,14 @@ connection_threadmain()
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                         }
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                     }
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                     slapi_ch_free_string(&anon_dn);
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+                    /*
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+                     * Set connection as initialized to avoid setting anonymous limits
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+                     * multiple times on the same connection
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+                     */
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+                    pb_conn->c_anonlimits_set = 1;
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                 }
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+                PR_ExitMonitor(pb_conn->c_mutex);
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+
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                 if (connection_call_io_layer_callbacks(pb_conn)) {
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                     slapi_log_err(SLAPI_LOG_ERR, "connection_threadmain",
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                                   "Could not add/remove IO layers from connection\n");
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diff --git a/ldap/servers/slapd/slap.h b/ldap/servers/slapd/slap.h
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index 9b10aa19e..03355f5fe 100644
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--- a/ldap/servers/slapd/slap.h
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+++ b/ldap/servers/slapd/slap.h
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@@ -1616,6 +1616,7 @@ typedef struct conn
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     PRUint64 c_maxthreadsblocked;    /* # of operations blocked by maxthreads */
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     int c_opsinitiated;              /* # ops initiated/next op id      */
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     PRInt32 c_opscompleted;          /* # ops completed          */
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+    uint64_t c_anonlimits_set;       /* default anon limits are set */
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     PRInt32 c_threadnumber;          /* # threads used in this conn    */
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     int c_refcnt;                    /* # ops refering to this conn    */
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     PRMonitor *c_mutex;              /* protect each conn structure; need to be re-entrant */
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@@ -1623,10 +1624,8 @@ typedef struct conn
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     time_t c_idlesince;              /* last time of activity on conn  */
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     int c_idletimeout;               /* local copy of idletimeout */
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     int c_idletimeout_handle;        /* the resource limits handle */
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-    Conn_private *c_private;         /* data which is not shared outside*/
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-                                     /* connection.c           */
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-    int c_flags;                     /* Misc flags used only for SSL   */
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-                                     /* status currently               */
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+    Conn_private *c_private;         /* data which is not shared outside connection.c */
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+    int c_flags;                     /* Misc flags used only for SSL status currently */
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     int c_needpw;                    /* need new password           */
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     CERTCertificate *c_client_cert;  /* Client's Cert          */
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     PRFileDesc *c_prfd;              /* NSPR 2.1 FileDesc          */
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-- 
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2.13.6
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