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Obstruct shell, SQL, and conninfo injection via database and role names.

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Due to simplistic quoting and confusion of database names with conninfo
strings, roles with the CREATEDB or CREATEROLE option could escalate to
superuser privileges when a superuser next ran certain maintenance
commands.  The new coding rule for PQconnectdbParams() calls, documented
at conninfo_array_parse(), is to pass expand_dbname=true and wrap
literal database names in a trivial connection string.  Escape
zero-length values in appendConnStrVal().  Back-patch to 9.1 (all
supported versions).

Nathan Bossart, Michael Paquier, and Noah Misch.  Reviewed by Peter
Eisentraut.  Reported by Nathan Bossart.

Security: CVE-2016-5424
This commit is contained in:
Noah Misch
2016-08-08 10:07:46 -04:00
parent d2dd5df514
commit a2385cac13
21 changed files with 572 additions and 193 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
contrib/pg_upgrade/check.c
View File

@ -218,9 +218,10 @@ issue_warnings(char *sequence_script_file_name)
prep_status("Adjusting sequences");
exec_prog(true,
SYSTEMQUOTE "\"%s/psql\" --set ON_ERROR_STOP=on "
"--no-psqlrc --port %d --username \"%s\" "
"--no-psqlrc --port %d --username %s "
"-f \"%s\" --dbname template1 >> \"%s\"" SYSTEMQUOTE,
new_cluster.bindir, new_cluster.port, os_info.user,
new_cluster.bindir, new_cluster.port,
os_info.user_shell_arg,
sequence_script_file_name, log_opts.filename);
unlink(sequence_script_file_name);
check_ok();

5
contrib/pg_upgrade/dump.c
View File

@ -21,10 +21,11 @@ generate_old_dump(void)
* restores the frozenid's for databases and relations.
*/
exec_prog(true,
SYSTEMQUOTE "\"%s/pg_dumpall\" --port %d --username \"%s\" "
SYSTEMQUOTE "\"%s/pg_dumpall\" --port %d --username %s "
"--schema-only --quote-all-identifiers --binary-upgrade "
"-f \"%s/" ALL_DUMP_FILE "\""
SYSTEMQUOTE, new_cluster.bindir, old_cluster.port, os_info.user, os_info.cwd);
SYSTEMQUOTE, new_cluster.bindir, old_cluster.port,
os_info.user_shell_arg, os_info.cwd);
check_ok();
}

6
contrib/pg_upgrade/option.c
View File

@ -52,6 +52,7 @@ parseCommandLine(int argc, char *argv[])
int option; /* Command line option */
int optindex = 0; /* used by getopt_long */
int os_user_effective_id;
PQExpBufferData userbuf;
user_opts.transfer_mode = TRANSFER_MODE_COPY;
@ -211,6 +212,11 @@ parseCommandLine(int argc, char *argv[])
"old cluster data resides");
validateDirectoryOption(&new_cluster.pgdata, "NEWDATADIR", "-D",
"new cluster data resides");
initPQExpBuffer(&userbuf);
appendShellString(&userbuf, os_info.user);
/* Abandon struct, but keep its buffer until process exit. */
os_info.user_shell_arg = userbuf.data;
}

18
contrib/pg_upgrade/pg_upgrade.c
View File

@ -359,9 +359,9 @@ prepare_new_cluster(void)
*/
prep_status("Analyzing all rows in the new cluster");
exec_prog(true,
SYSTEMQUOTE "\"%s/vacuumdb\" --port %d --username \"%s\" "
SYSTEMQUOTE "\"%s/vacuumdb\" --port %d --username %s "
"--all --analyze >> \"%s\" 2>&1" SYSTEMQUOTE,
new_cluster.bindir, new_cluster.port, os_info.user,
new_cluster.bindir, new_cluster.port, os_info.user_shell_arg,
#ifndef WIN32
log_opts.filename
#else
@ -378,9 +378,9 @@ prepare_new_cluster(void)
*/
prep_status("Freezing all rows on the new cluster");
exec_prog(true,
SYSTEMQUOTE "\"%s/vacuumdb\" --port %d --username \"%s\" "
SYSTEMQUOTE "\"%s/vacuumdb\" --port %d --username %s "
"--all --freeze >> \"%s\" 2>&1" SYSTEMQUOTE,
new_cluster.bindir, new_cluster.port, os_info.user,
new_cluster.bindir, new_cluster.port, os_info.user_shell_arg,
#ifndef WIN32
log_opts.filename
#else
@ -421,9 +421,10 @@ prepare_new_databases(void)
exec_prog(true,
SYSTEMQUOTE "\"%s/psql\" --set ON_ERROR_STOP=on "
/* --no-psqlrc prevents AUTOCOMMIT=off */
"--no-psqlrc --port %d --username \"%s\" "
"--no-psqlrc --port %d --username %s "
"-f \"%s/%s\" --dbname template1 >> \"%s\"" SYSTEMQUOTE,
new_cluster.bindir, new_cluster.port, os_info.user, os_info.cwd,
new_cluster.bindir, new_cluster.port,
os_info.user_shell_arg, os_info.cwd,
GLOBALS_DUMP_FILE,
#ifndef WIN32
log_opts.filename
@ -458,9 +459,10 @@ create_new_objects(void)
prep_status("Restoring database schema to new cluster");
exec_prog(true,
SYSTEMQUOTE "\"%s/psql\" --set ON_ERROR_STOP=on "
"--no-psqlrc --port %d --username \"%s\" "
"--no-psqlrc --port %d --username %s "
"-f \"%s/%s\" --dbname template1 >> \"%s\"" SYSTEMQUOTE,
new_cluster.bindir, new_cluster.port, os_info.user, os_info.cwd,
new_cluster.bindir, new_cluster.port,
os_info.user_shell_arg, os_info.cwd,
DB_DUMP_FILE,
#ifndef WIN32
log_opts.filename

5
contrib/pg_upgrade/pg_upgrade.h
View File

@ -14,6 +14,7 @@
#include <sys/time.h>
#include "libpq-fe.h"
#include "pqexpbuffer.h"
/* Allocate for null byte */
#define USER_NAME_SIZE 128
@ -236,6 +237,7 @@ typedef struct
const char *progname; /* complete pathname for this program */
char *exec_path; /* full path to my executable */
char *user; /* username for clusters */
char *user_shell_arg; /* the same, with shell quoting */
char cwd[MAXPGPATH]; /* current working directory, used for output */
char **tablespaces; /* tablespaces */
int num_tablespaces;
@ -381,6 +383,9 @@ void check_pghost_envvar(void);
/* util.c */
char *quote_identifier(const char *s);
extern void appendShellString(PQExpBuffer buf, const char *str);
extern void appendConnStrVal(PQExpBuffer buf, const char *str);
extern void appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname);
int get_user_info(char **user_name);
void check_ok(void);
void report_status(eLogType type, const char *fmt,...);

17
contrib/pg_upgrade/server.c
View File

@ -49,13 +49,20 @@ connectToServer(ClusterInfo *cluster, const char *db_name)
static PGconn *
get_db_conn(ClusterInfo *cluster, const char *db_name)
{
char conn_opts[MAXPGPATH];
PQExpBufferData conn_opts;
PGconn *conn;
snprintf(conn_opts, sizeof(conn_opts),
"dbname = '%s' user = '%s' port = %d", db_name, os_info.user,
cluster->port);
/* Build connection string with proper quoting */
initPQExpBuffer(&conn_opts);
appendPQExpBufferStr(&conn_opts, "dbname=");
appendConnStrVal(&conn_opts, db_name);
appendPQExpBufferStr(&conn_opts, " user=");
appendConnStrVal(&conn_opts, os_info.user);
appendPQExpBuffer(&conn_opts, " port=%d", cluster->port);
return PQconnectdb(conn_opts);
conn = PQconnectdb(conn_opts.data);
termPQExpBuffer(&conn_opts);
return conn;
}

204
contrib/pg_upgrade/util.c
View File

@ -151,6 +151,210 @@ quote_identifier(const char *s)
}
/*
* Append the given string to the shell command being built in the buffer,
* with suitable shell-style quoting to create exactly one argument.
*
* Forbid LF or CR characters, which have scant practical use beyond designing
* security breaches. The Windows command shell is unusable as a conduit for
* arguments containing LF or CR characters. A future major release should
* reject those characters in CREATE ROLE and CREATE DATABASE, because use
* there eventually leads to errors here.
*/
void
appendShellString(PQExpBuffer buf, const char *str)
{
const char *p;
#ifndef WIN32
appendPQExpBufferChar(buf, '\'');
for (p = str; *p; p++)
{
if (*p == '\n' || *p == '\r')
{
fprintf(stderr,
_("shell command argument contains a newline or carriage return: \"%s\"\n"),
str);
exit(EXIT_FAILURE);
}
if (*p == '\'')
appendPQExpBufferStr(buf, "'\"'\"'");
else
appendPQExpBufferChar(buf, *p);
}
appendPQExpBufferChar(buf, '\'');
#else /* WIN32 */
int backslash_run_length = 0;
/*
* A Windows system() argument experiences two layers of interpretation.
* First, cmd.exe interprets the string. Its behavior is undocumented,
* but a caret escapes any byte except LF or CR that would otherwise have
* special meaning. Handling of a caret before LF or CR differs between
* "cmd.exe /c" and other modes, and it is unusable here.
*
* Second, the new process parses its command line to construct argv (see
* https://msdn.microsoft.com/en-us/library/17w5ykft.aspx). This treats
* backslash-double quote sequences specially.
*/
appendPQExpBufferStr(buf, "^\"");
for (p = str; *p; p++)
{
if (*p == '\n' || *p == '\r')
{
fprintf(stderr,
_("shell command argument contains a newline or carriage return: \"%s\"\n"),
str);
exit(EXIT_FAILURE);
}
/* Change N backslashes before a double quote to 2N+1 backslashes. */
if (*p == '"')
{
while (backslash_run_length)
{
appendPQExpBufferStr(buf, "^\\");
backslash_run_length--;
}
appendPQExpBufferStr(buf, "^\\");
}
else if (*p == '\\')
backslash_run_length++;
else
backslash_run_length = 0;
/*
* Decline to caret-escape the most mundane characters, to ease
* debugging and lest we approach the command length limit.
*/
if (!((*p >= 'a' && *p <= 'z') ||
(*p >= 'A' && *p <= 'Z') ||
(*p >= '0' && *p <= '9')))
appendPQExpBufferChar(buf, '^');
appendPQExpBufferChar(buf, *p);
}
/*
* Change N backslashes at end of argument to 2N backslashes, because they
* precede the double quote that terminates the argument.
*/
while (backslash_run_length)
{
appendPQExpBufferStr(buf, "^\\");
backslash_run_length--;
}
appendPQExpBufferStr(buf, "^\"");
#endif /* WIN32 */
}
/*
* Append the given string to the buffer, with suitable quoting for passing
* the string as a value, in a keyword/pair value in a libpq connection
* string
*/
void
appendConnStrVal(PQExpBuffer buf, const char *str)
{
const char *s;
bool needquotes;
/*
* If the string is one or more plain ASCII characters, no need to quote
* it. This is quite conservative, but better safe than sorry.
*/
needquotes = true;
for (s = str; *s; s++)
{
if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
(*s >= '0' && *s <= '9') || *s == '_' || *s == '.'))
{
needquotes = true;
break;
}
needquotes = false;
}
if (needquotes)
{
appendPQExpBufferChar(buf, '\'');
while (*str)
{
/* ' and \ must be escaped by to \' and \\ */
if (*str == '\'' || *str == '\\')
appendPQExpBufferChar(buf, '\\');
appendPQExpBufferChar(buf, *str);
str++;
}
appendPQExpBufferChar(buf, '\'');
}
else
appendPQExpBufferStr(buf, str);
}
/*
* Append a psql meta-command that connects to the given database with the
* then-current connection's user, host and port.
*/
void
appendPsqlMetaConnect(PQExpBuffer buf, const char *dbname)
{
const char *s;
bool complex;
/*
* If the name is plain ASCII characters, emit a trivial "\connect "foo"".
* For other names, even many not technically requiring it, skip to the
* general case. No database has a zero-length name.
*/
complex = false;
for (s = dbname; *s; s++)
{
if (*s == '\n' || *s == '\r')
{
fprintf(stderr,
_("database name contains a newline or carriage return: \"%s\"\n"),
dbname);
exit(EXIT_FAILURE);
}
if (!((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
(*s >= '0' && *s <= '9') || *s == '_' || *s == '.'))
{
complex = true;
}
}
appendPQExpBufferStr(buf, "\\connect ");
if (complex)
{
PQExpBufferData connstr;
initPQExpBuffer(&connstr);
appendPQExpBuffer(&connstr, "dbname=");
appendConnStrVal(&connstr, dbname);
appendPQExpBuffer(buf, "-reuse-previous=on ");
/*
* As long as the name does not contain a newline, SQL identifier
* quoting satisfies the psql meta-command parser. Prefer not to
* involve psql-interpreted single quotes, which behaved differently
* before PostgreSQL 9.2.
*/
appendPQExpBufferStr(buf, quote_identifier(connstr.data));
termPQExpBuffer(&connstr);
}
else
appendPQExpBufferStr(buf, quote_identifier(dbname));
appendPQExpBufferChar(buf, '\n');
}
/*
* get_user_info()
* (copied from initdb.c) find the current user

10
contrib/pg_upgrade/version.c
View File

@ -48,10 +48,16 @@ new_9_0_populate_pg_largeobject_metadata(ClusterInfo *cluster, bool check_mode)
found = true;
if (!check_mode)
{
PQExpBufferData connectbuf;
if (script == NULL && (script = fopen(output_path, "w")) == NULL)
pg_log(PG_FATAL, "could not create necessary file: %s\n", output_path);
fprintf(script, "\\connect %s\n",
quote_identifier(active_db->db_name));
initPQExpBuffer(&connectbuf);
appendPsqlMetaConnect(&connectbuf, active_db->db_name);
fputs(connectbuf.data, script);
termPQExpBuffer(&connectbuf);
fprintf(script,
"SELECT pg_catalog.lo_create(t.loid)\n"
"FROM (SELECT DISTINCT loid FROM pg_catalog.pg_largeobject) AS t;\n");

34
contrib/pg_upgrade/version_old_8_3.c
View File

@ -368,8 +368,13 @@ old_8_3_rebuild_tsvector_tables(ClusterInfo *cluster, bool check_mode)
pg_log(PG_FATAL, "could not create necessary file: %s\n", output_path);
if (!db_used)
{
fprintf(script, "\\connect %s\n\n",
quote_identifier(active_db->db_name));
PQExpBufferData connectbuf;
initPQExpBuffer(&connectbuf);
appendPsqlMetaConnect(&connectbuf, active_db->db_name);
appendPQExpBufferChar(&connectbuf, '\n');
fputs(connectbuf.data, script);
termPQExpBuffer(&connectbuf);
db_used = true;
}
@ -488,8 +493,12 @@ old_8_3_invalidate_hash_gin_indexes(ClusterInfo *cluster, bool check_mode)
pg_log(PG_FATAL, "could not create necessary file: %s\n", output_path);
if (!db_used)
{
fprintf(script, "\\connect %s\n",
quote_identifier(active_db->db_name));
PQExpBufferData connectbuf;
initPQExpBuffer(&connectbuf);
appendPsqlMetaConnect(&connectbuf, active_db->db_name);
fputs(connectbuf.data, script);
termPQExpBuffer(&connectbuf);
db_used = true;
}
fprintf(script, "REINDEX INDEX %s.%s;\n",
@ -613,8 +622,12 @@ old_8_3_invalidate_bpchar_pattern_ops_indexes(ClusterInfo *cluster,
pg_log(PG_FATAL, "could not create necessary file: %s\n", output_path);
if (!db_used)
{
fprintf(script, "\\connect %s\n",
quote_identifier(active_db->db_name));
PQExpBufferData connectbuf;
initPQExpBuffer(&connectbuf);
appendPsqlMetaConnect(&connectbuf, active_db->db_name);
fputs(connectbuf.data, script);
termPQExpBuffer(&connectbuf);
db_used = true;
}
fprintf(script, "REINDEX INDEX %s.%s;\n",
@ -740,8 +753,13 @@ old_8_3_create_sequence_script(ClusterInfo *cluster)
pg_log(PG_FATAL, "could not create necessary file: %s\n", output_path);
if (!db_used)
{
fprintf(script, "\\connect %s\n\n",
quote_identifier(active_db->db_name));
PQExpBufferData connectbuf;
initPQExpBuffer(&connectbuf);
appendPsqlMetaConnect(&connectbuf, active_db->db_name);
appendPQExpBufferChar(&connectbuf, '\n');
fputs(connectbuf.data, script);
termPQExpBuffer(&connectbuf);
db_used = true;
}