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postgres/contrib/adminpack/adminpack.c
Stephen Frost 11523e860f Support new default roles with adminpack 
This provides a newer version of adminpack which works with the newly
added default roles to support GRANT'ing to non-superusers access to
read and write files, along with related functions (unlinking files,
getting file length, renaming/removing files, scanning the log file
directory) which are supported through adminpack.

Note that new versions of the functions are required because an
environment might have an updated version of the library but still have
the old adminpack 1.0 catalog definitions (where EXECUTE is GRANT'd to
PUBLIC for the functions).

This patch also removes the long-deprecated alternative names for
functions that adminpack used to include and which are now included in
the backend, in adminpack v1.1.  Applications using the deprecated names
should be updated to use the backend functions instead.  Existing
installations which continue to use adminpack v1.0 should continue to
function until/unless adminpack is upgraded.

Reviewed-By: Michael Paquier
Discussion: https://postgr.es/m/20171231191939.GR2416%40tamriel.snowman.net
2018-04-06 14:47:10 -04:00

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/*-------------------------------------------------------------------------
*
* adminpack.c
*
*
* Copyright (c) 2002-2018, PostgreSQL Global Development Group
*
* Author: Andreas Pflug <pgadmin@pse-consulting.de>
*
* IDENTIFICATION
* contrib/adminpack/adminpack.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include <sys/file.h>
#include <sys/stat.h>
#include <unistd.h>
#include "catalog/pg_authid.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "postmaster/syslogger.h"
#include "storage/fd.h"
#include "utils/builtins.h"
#include "utils/datetime.h"
#ifdef WIN32
#ifdef rename
#undef rename
#endif
#ifdef unlink
#undef unlink
#endif
#endif
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(pg_file_write);
PG_FUNCTION_INFO_V1(pg_file_write_v1_1);
PG_FUNCTION_INFO_V1(pg_file_rename);
PG_FUNCTION_INFO_V1(pg_file_rename_v1_1);
PG_FUNCTION_INFO_V1(pg_file_unlink);
PG_FUNCTION_INFO_V1(pg_file_unlink_v1_1);
PG_FUNCTION_INFO_V1(pg_logdir_ls);
PG_FUNCTION_INFO_V1(pg_logdir_ls_v1_1);
static int64 pg_file_write_internal(text *file, text *data, bool replace);
static bool pg_file_rename_internal(text *file1, text *file2, text *file3);
static Datum pg_logdir_ls_internal(FunctionCallInfo fcinfo);
typedef struct
{
char *location;
DIR *dirdesc;
} directory_fctx;
/*-----------------------
* some helper functions
*/
/*
* Convert a "text" filename argument to C string, and check it's allowable.
*
* Filename may be absolute or relative to the DataDir, but we only allow
* absolute paths that match DataDir or Log_directory.
*/
static char *
convert_and_check_filename(text *arg, bool logAllowed)
{
char *filename = text_to_cstring(arg);
canonicalize_path(filename); /* filename can change length here */
/*
* Members of the 'pg_write_server_files' role are allowed to access any
* files on the server as the PG user, so no need to do any further checks
* here.
*/
if (is_member_of_role(GetUserId(), DEFAULT_ROLE_WRITE_SERVER_FILES))
return filename;
/* User isn't a member of the default role, so check if it's allowable */
if (is_absolute_path(filename))
{
/* Disallow '/a/b/data/..' */
if (path_contains_parent_reference(filename))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("reference to parent directory (\"..\") not allowed"))));
/*
* Allow absolute paths if within DataDir or Log_directory, even
* though Log_directory might be outside DataDir.
*/
if (!path_is_prefix_of_path(DataDir, filename) &&
(!logAllowed || !is_absolute_path(Log_directory) ||
!path_is_prefix_of_path(Log_directory, filename)))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("absolute path not allowed"))));
}
else if (!path_is_relative_and_below_cwd(filename))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("path must be in or below the current directory"))));
return filename;
}
/*
* check for superuser, bark if not.
*/
static void
requireSuperuser(void)
{
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("only superuser may access generic file functions"))));
}
/* ------------------------------------
* pg_file_write - old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_file_write(PG_FUNCTION_ARGS)
{
text *file = PG_GETARG_TEXT_PP(0);
text *data = PG_GETARG_TEXT_PP(1);
bool replace = PG_GETARG_BOOL(2);
int64 count = 0;
requireSuperuser();
count = pg_file_write_internal(file, data, replace);
PG_RETURN_INT64(count);
}
/* ------------------------------------
* pg_file_write_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_file_write (above).
*/
Datum
pg_file_write_v1_1(PG_FUNCTION_ARGS)
{
text *file = PG_GETARG_TEXT_PP(0);
text *data = PG_GETARG_TEXT_PP(1);
bool replace = PG_GETARG_BOOL(2);
int64 count = 0;
count = pg_file_write_internal(file, data, replace);
PG_RETURN_INT64(count);
}
/* ------------------------------------
* pg_file_write_internal - Workhorse for pg_file_write functions.
*
* This handles the actual work for pg_file_write.
*/
int64
pg_file_write_internal(text *file, text *data, bool replace)
{
FILE *f;
char *filename;
int64 count = 0;
filename = convert_and_check_filename(file, false);
if (!replace)
{
struct stat fst;
if (stat(filename, &fst) >= 0)
ereport(ERROR,
(ERRCODE_DUPLICATE_FILE,
errmsg("file \"%s\" exists", filename)));
f = AllocateFile(filename, "wb");
}
else
f = AllocateFile(filename, "ab");
if (!f)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\" for writing: %m",
filename)));
count = fwrite(VARDATA_ANY(data), 1, VARSIZE_ANY_EXHDR(data), f);
if (count != VARSIZE_ANY_EXHDR(data) || FreeFile(f))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not write file \"%s\": %m", filename)));
return (count);
}
/* ------------------------------------
* pg_file_rename - old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_file_rename(PG_FUNCTION_ARGS)
{
text *file1;
text *file2;
text *file3;
bool result;
requireSuperuser();
if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
PG_RETURN_NULL();
file1 = PG_GETARG_TEXT_PP(0);
file2 = PG_GETARG_TEXT_PP(1);
if (PG_ARGISNULL(2))
file3 = NULL;
else
file3 = PG_GETARG_TEXT_PP(2);
result = pg_file_rename_internal(file1, file2, file3);
PG_RETURN_BOOL(result);
}
/* ------------------------------------
* pg_file_rename_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_file_write (above).
*/
Datum
pg_file_rename_v1_1(PG_FUNCTION_ARGS)
{
text *file1;
text *file2;
text *file3;
bool result;
if (PG_ARGISNULL(0) || PG_ARGISNULL(1))
PG_RETURN_NULL();
file1 = PG_GETARG_TEXT_PP(0);
file2 = PG_GETARG_TEXT_PP(1);
if (PG_ARGISNULL(2))
file3 = NULL;
else
file3 = PG_GETARG_TEXT_PP(2);
result = pg_file_rename_internal(file1, file2, file3);
PG_RETURN_BOOL(result);
}
/* ------------------------------------
* pg_file_rename_internal - Workhorse for pg_file_rename functions.
*
* This handles the actual work for pg_file_rename.
*/
bool
pg_file_rename_internal(text *file1, text *file2, text *file3)
{
char *fn1,
*fn2,
*fn3;
int rc;
fn1 = convert_and_check_filename(file1, false);
fn2 = convert_and_check_filename(file2, false);
if (file3 == NULL)
fn3 = 0;
else
fn3 = convert_and_check_filename(file3, false);
if (access(fn1, W_OK) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", fn1)));
return false;
}
if (fn3 && access(fn2, W_OK) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", fn2)));
return false;
}
rc = access(fn3 ? fn3 : fn2, 2);
if (rc >= 0 || errno != ENOENT)
{
ereport(ERROR,
(ERRCODE_DUPLICATE_FILE,
errmsg("cannot rename to target file \"%s\"",
fn3 ? fn3 : fn2)));
}
if (fn3)
{
if (rename(fn2, fn3) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" to \"%s\": %m",
fn2, fn3)));
}
if (rename(fn1, fn2) != 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" to \"%s\": %m",
fn1, fn2)));
if (rename(fn3, fn2) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" back to \"%s\": %m",
fn3, fn2)));
}
else
{
ereport(ERROR,
(ERRCODE_UNDEFINED_FILE,
errmsg("renaming \"%s\" to \"%s\" was reverted",
fn2, fn3)));
}
}
}
else if (rename(fn1, fn2) != 0)
{
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not rename \"%s\" to \"%s\": %m", fn1, fn2)));
}
return true;
}
/* ------------------------------------
* pg_file_unlink - old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_file_unlink(PG_FUNCTION_ARGS)
{
char *filename;
requireSuperuser();
filename = convert_and_check_filename(PG_GETARG_TEXT_PP(0), false);
if (access(filename, W_OK) < 0)
{
if (errno == ENOENT)
PG_RETURN_BOOL(false);
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", filename)));
}
if (unlink(filename) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not unlink file \"%s\": %m", filename)));
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(true);
}
/* ------------------------------------
* pg_file_unlink_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_file_unlink (above).
*/
Datum
pg_file_unlink_v1_1(PG_FUNCTION_ARGS)
{
char *filename;
filename = convert_and_check_filename(PG_GETARG_TEXT_PP(0), false);
if (access(filename, W_OK) < 0)
{
if (errno == ENOENT)
PG_RETURN_BOOL(false);
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("file \"%s\" is not accessible: %m", filename)));
}
if (unlink(filename) < 0)
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not unlink file \"%s\": %m", filename)));
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(true);
}
/* ------------------------------------
* pg_logdir_ls - Old version
*
* The superuser() check here must be kept as the library might be upgraded
* without the extension being upgraded, meaning that in pre-1.1 installations
* these functions could be called by any user.
*/
Datum
pg_logdir_ls(PG_FUNCTION_ARGS)
{
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("only superuser can list the log directory"))));
return (pg_logdir_ls_internal(fcinfo));
}
/* ------------------------------------
* pg_logdir_ls_v1_1 - Version 1.1
*
* As of adminpack version 1.1, we no longer need to check if the user
* is a superuser because we REVOKE EXECUTE on the function from PUBLIC.
* Users can then grant access to it based on their policies.
*
* Otherwise identical to pg_logdir_ls (above).
*/
Datum
pg_logdir_ls_v1_1(PG_FUNCTION_ARGS)
{
return (pg_logdir_ls_internal(fcinfo));
}
Datum
pg_logdir_ls_internal(FunctionCallInfo fcinfo)
{
FuncCallContext *funcctx;
struct dirent *de;
directory_fctx *fctx;
if (strcmp(Log_filename, "postgresql-%Y-%m-%d_%H%M%S.log") != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
(errmsg("the log_filename parameter must equal 'postgresql-%%Y-%%m-%%d_%%H%%M%%S.log'"))));
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
TupleDesc tupdesc;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
fctx = palloc(sizeof(directory_fctx));
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starttime",
TIMESTAMPOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "filename",
TEXTOID, -1, 0);
funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
fctx->location = pstrdup(Log_directory);
fctx->dirdesc = AllocateDir(fctx->location);
if (!fctx->dirdesc)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
fctx->location)));
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
fctx = (directory_fctx *) funcctx->user_fctx;
while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
{
char *values[2];
HeapTuple tuple;
char timestampbuf[32];
char *field[MAXDATEFIELDS];
char lowstr[MAXDATELEN + 1];
int dtype;
int nf,
ftype[MAXDATEFIELDS];
fsec_t fsec;
int tz = 0;
struct pg_tm date;
/*
* Default format: postgresql-YYYY-MM-DD_HHMMSS.log
*/
if (strlen(de->d_name) != 32
|| strncmp(de->d_name, "postgresql-", 11) != 0
|| de->d_name[21] != '_'
|| strcmp(de->d_name + 28, ".log") != 0)
continue;
/* extract timestamp portion of filename */
strcpy(timestampbuf, de->d_name + 11);
timestampbuf[17] = '\0';
/* parse and decode expected timestamp to verify it's OK format */
if (ParseDateTime(timestampbuf, lowstr, MAXDATELEN, field, ftype, MAXDATEFIELDS, &nf))
continue;
if (DecodeDateTime(field, ftype, nf, &dtype, &date, &fsec, &tz))
continue;
/* Seems the timestamp is OK; prepare and return tuple */
values[0] = timestampbuf;
values[1] = psprintf("%s/%s", fctx->location, de->d_name);
tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
}
FreeDir(fctx->dirdesc);
SRF_RETURN_DONE(funcctx);
}
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