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Introduce a psql "\connect -reuse-previous=on|off" option.

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The decision to reuse values of parameters from a previous connection
has been based on whether the new target is a conninfo string.  Add this
means of overriding that default.  This feature arose as one component
of a fix for security vulnerabilities in pg_dump, pg_dumpall, and
pg_upgrade, so back-patch to 9.1 (all supported versions).  In 9.3 and
later, comment paragraphs that required update had already-incorrect
claims about behavior when no connection is open; fix those problems.

Security: CVE-2016-5424
This commit is contained in:
Noah Misch
2016-08-08 10:07:46 -04:00
parent 984e5beb38
commit 9d924e9a64
3 changed files with 90 additions and 46 deletions
Download Patch File Download Diff File Expand all files Collapse all files

113
src/bin/psql/command.c
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@ -65,7 +65,8 @@ static backslashResult exec_command(const char *cmd,
PQExpBuffer query_buf);
static bool do_edit(const char *filename_arg, PQExpBuffer query_buf,
int lineno, bool *edited);
static bool do_connect(char *dbname, char *user, char *host, char *port);
static bool do_connect(enum trivalue reuse_previous_specification,
char *dbname, char *user, char *host, char *port);
static bool do_shell(const char *command);
static bool do_watch(PQExpBuffer query_buf, double sleep);
static bool lookup_object_oid(EditableObjectType obj_type, const char *desc,
@ -231,12 +232,9 @@ exec_command(const char *cmd,
/*
* \c or \connect -- connect to database using the specified parameters.
*
* \c dbname user host port
* \c [-reuse-previous=BOOL] dbname user host port
*
* If any of these parameters are omitted or specified as '-', the current
* value of the parameter will be used instead. If the parameter has no
* current value, the default value for that parameter will be used. Some
* examples:
* Specifying a parameter as '-' is equivalent to omitting it. Examples:
*
* \c - - hst Connect to current database on current port of host
* "hst" as current user. \c - usr - prt Connect to current database on
@ -245,17 +243,31 @@ exec_command(const char *cmd,
*/
else if (strcmp(cmd, "c") == 0 || strcmp(cmd, "connect") == 0)
{
static const char prefix[] = "-reuse-previous=";
char *opt1,
*opt2,
*opt3,
*opt4;
enum trivalue reuse_previous;
opt1 = read_connect_arg(scan_state);
if (opt1 != NULL && strncmp(opt1, prefix, sizeof(prefix) - 1) == 0)
{
reuse_previous =
ParseVariableBool(opt1 + sizeof(prefix) - 1, prefix) ?
TRI_YES : TRI_NO;
free(opt1);
opt1 = read_connect_arg(scan_state);
}
else
reuse_previous = TRI_DEFAULT;
opt2 = read_connect_arg(scan_state);
opt3 = read_connect_arg(scan_state);
opt4 = read_connect_arg(scan_state);
success = do_connect(opt1, opt2, opt3, opt4);
success = do_connect(reuse_previous, opt1, opt2, opt3, opt4);
free(opt1);
free(opt2);
@ -1754,22 +1766,25 @@ param_is_newly_set(const char *old_val, const char *new_val)
/*
* do_connect -- handler for \connect
*
* Connects to a database with given parameters. If there exists an
* established connection, NULL values will be replaced with the ones
* in the current connection. Otherwise NULL will be passed for that
* parameter to PQconnectdbParams(), so the libpq defaults will be used.
* Connects to a database with given parameters. Absent an established
* connection, all parameters are required. Given -reuse-previous=off or a
* connection string without -reuse-previous=on, NULL values will pass through
* to PQconnectdbParams(), so the libpq defaults will be used. Otherwise, NULL
* values will be replaced with the ones in the current connection.
*
* In interactive mode, if connection fails with the given parameters,
* the old connection will be kept.
*/
static bool
do_connect(char *dbname, char *user, char *host, char *port)
do_connect(enum trivalue reuse_previous_specification,
char *dbname, char *user, char *host, char *port)
{
PGconn *o_conn = pset.db,
*n_conn;
char *password = NULL;
bool keep_password;
bool has_connection_string;
bool reuse_previous;
if (!o_conn && (!dbname || !user || !host || !port))
{
@ -1783,16 +1798,35 @@ do_connect(char *dbname, char *user, char *host, char *port)
return false;
}
/* grab values from the old connection, unless supplied by caller */
if (!user)
user = PQuser(o_conn);
if (!host)
host = PQhost(o_conn);
if (!port)
port = PQport(o_conn);
has_connection_string = dbname ?
recognized_connection_string(dbname) : false;
switch (reuse_previous_specification)
{
case TRI_YES:
reuse_previous = true;
break;
case TRI_NO:
reuse_previous = false;
break;
default:
reuse_previous = !has_connection_string;
break;
}
/* Silently ignore arguments subsequent to a connection string. */
if (has_connection_string)
{
user = NULL;
host = NULL;
port = NULL;
}
has_connection_string =
dbname ? recognized_connection_string(dbname) : false;
/* grab missing values from the old connection */
if (!user && reuse_previous)
user = PQuser(o_conn);
if (!host && reuse_previous)
host = PQhost(o_conn);
if (!port && reuse_previous)
port = PQport(o_conn);
/*
* Any change in the parameters read above makes us discard the password.
@ -1808,10 +1842,10 @@ do_connect(char *dbname, char *user, char *host, char *port)
(port && PQport(o_conn) && strcmp(port, PQport(o_conn)) == 0);
/*
* Grab dbname from old connection unless supplied by caller. No password
* discard if this changes: passwords aren't (usually) database-specific.
* Grab missing dbname from old connection. No password discard if this
* changes: passwords aren't (usually) database-specific.
*/
if (!dbname)
if (!dbname && reuse_previous)
dbname = PQdb(o_conn);
/*
@ -1842,20 +1876,27 @@ do_connect(char *dbname, char *user, char *host, char *port)
#define PARAMS_ARRAY_SIZE 8
const char **keywords = pg_malloc(PARAMS_ARRAY_SIZE * sizeof(*keywords));
const char **values = pg_malloc(PARAMS_ARRAY_SIZE * sizeof(*values));
int paramnum = 0;
int paramnum = -1;
keywords[0] = "dbname";
values[0] = dbname;
keywords[++paramnum] = "host";
values[paramnum] = host;
keywords[++paramnum] = "port";
values[paramnum] = port;
keywords[++paramnum] = "user";
values[paramnum] = user;
if (!has_connection_string)
{
keywords[++paramnum] = "host";
values[paramnum] = host;
keywords[++paramnum] = "port";
values[paramnum] = port;
keywords[++paramnum] = "user";
values[paramnum] = user;
}
/*
* Position in the array matters when the dbname is a connection
* string, because settings in a connection string override earlier
* array entries only. Thus, user= in the connection string always
* takes effect, but client_encoding= often will not.
*
* If you change this code, also change the initial-connection code in
* main(). For no good reason, a connection string password= takes
* precedence in main() but not here.
*/
keywords[++paramnum] = "dbname";
values[paramnum] = dbname;
keywords[++paramnum] = "password";
values[paramnum] = password;
keywords[++paramnum] = "fallback_application_name";