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/*
* Copyright (c) 2012, Manuel Mausz <manuel at mausz dot at>,
* All rights reserved.
*
* Some maildir specified code is copied from dovecot (dovecot.org),
* Copyright by Timo Sirainen <tss at iki dot fi> (and others).
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <pwd.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#define MAILDIR_NAME "Maildir"
#define MAILDIRSIZE_FILENAME "maildirsize"
#define LOGPREFIX "QUOTA: "
struct maildir_quota
{
const char *file;
uint64_t total_bytes;
uint64_t total_count;
uint64_t bytes_limit;
uint64_t count_limit;
};
int check_parent(const char *username)
{
pid_t parent;
int num;
char buf[256], buf2[256];
const char *smtpbin = "/var/qmail/bin/qmail-smtpd";
/* check parent */
parent = getppid();
num = snprintf(buf, sizeof(buf), "/proc/%d/exe", parent);
if (num < 0 || num > sizeof(buf))
{
(void)fprintf(stderr, LOGPREFIX "Unable to copy string to buffer for user \"%s\".\n", username);
return 0;
}
num = readlink(buf, buf2, sizeof(buf2));
if (num < 0)
{
(void)fprintf(stderr, LOGPREFIX "Unable to read parent from proc-fs for user \"%s\": %m\n", username);
return 0;
}
buf2[num] = '\0';
if (strcmp(smtpbin, buf2) != 0)
{
(void)fprintf(stderr, LOGPREFIX "Error: Parent \"%s\" doesn't match qmail-smtp for user \"%s\".\n", buf2, username);
return 0;
}
return 1;
}
int maildir_file_read(const char *file, char *buf, size_t size)
{
unsigned int readb;
int fd, num, i;
fd = open(file, O_RDONLY);
if (fd == -1)
{
/* no file, no quota */
if (errno != ENOENT)
(void)fprintf(stderr, LOGPREFIX "Unable to open maildirsize-file \"%s\": %m\n", file);
return 0;
}
/* read the whole file into our buffer. we won't do any
recalculations, dovecot will do this for us */
readb = 0;
while ((num = read(fd, buf + readb, size - readb)) != 0)
{
readb += num;
if (readb >= size)
break;
}
(void)close(fd);
/* skip the last line if there's no LF at the end. Remove the last LF
so we don't get one empty line in the strsplit */
while (readb > 0 && buf[readb - 1] != '\n')
readb--;
if (readb > 0)
readb--;
buf[readb] = '\0';
/* the read failed and there's no usable header, fail */
if (num < 0 && readb == 0)
{
(void)fprintf(stderr, LOGPREFIX "Error while reading maildirsize-file \"%s\": %m\n", file);
return 0;
}
/* if there are any NUL bytes, the file is broken */
for (i = 0; i < readb; i++)
{
if (buf[i] == '\0')
{
(void)fprintf(stderr, LOGPREFIX "Invalid NUL-characters in maildirsize-file \"%s\"\n", file);
return 0;
}
}
return readb;
}
int maildir_parse_header(char *str, uint64_t *bytes, uint64_t *count)
{
char *limit, *saveptr, *pos;
unsigned long long value;
bool ret = true;
if (str == NULL)
return false;
*bytes = 0;
*count = 0;
/* 0 values mean unlimited */
while((limit = strtok_r(str, ",", &saveptr)))
{
value = strtoull(limit, &pos, 10);
if (pos[0] != '\0' && pos[1] == '\0')
{
switch (pos[0]) {
case 'C':
if (value != 0)
*count = value;
break;
case 'S':
if (value != 0)
*bytes = value;
break;
default:
ret = false;
break;
}
}
else
ret = false;
str = NULL;
}
return ret;
}
int maildir_file_parse(struct maildir_quota *quota, char *buf)
{
char *line, *saveptr;
long long total_bytes, bytes_diff;
int total_count, count_diff;
/* first line contains the limits */
if (buf == NULL || !(line = strtok_r(buf, "\n", &saveptr)))
{
(void)fprintf(stderr, LOGPREFIX "No or invalid header in maildirsize-file \"%s\"\n", quota->file);
return 0;
}
if (!maildir_parse_header(line, "a->bytes_limit, "a->count_limit))
{
(void)fprintf(stderr, LOGPREFIX "Unable to parse header in maildirsize-file \"%s\"\n", quota->file);
return 0;
}
/* truncate too high limits to signed 64bit int range */
if (quota->bytes_limit >= (1ULL << 63))
quota->bytes_limit = (1ULL << 63) - 1;
if (quota->count_limit >= (1ULL << 63))
quota->count_limit = (1ULL << 63) - 1;
/* rest of the lines contains <bytes> <count> diffs */
total_bytes = total_count = 0;
while((line = strtok_r(NULL, "\n", &saveptr)))
{
if (sscanf(line, "%lld %d", &bytes_diff, &count_diff) != 2)
{
(void)fprintf(stderr, LOGPREFIX "Invalid content maildirsize-file in \"%s\": %s\n",
quota->file, line);
return 0;
}
total_bytes += bytes_diff;
total_count += count_diff;
}
/* corrupted */
if (total_bytes < 0 || total_count < 0)
{
(void)fprintf(stderr, LOGPREFIX "Corrupted maildirsize-file \"%s\": total_bytes=%lld, total_count=%d\n",
quota->file, total_bytes, total_count);
return 0;
}
quota->total_bytes = (uint64_t)total_bytes;
quota->total_count = (uint64_t)total_count;
return 1;
}
int main()
{
const char *username = NULL;
struct maildir_quota quota;
struct passwd *pw;
char path[PATH_MAX];
char buf[5120 + 100 + 1]; /* dovecot will recalculate at 5120 bytes for us */
int num;
username = getenv("DTUSER");
if (!username)
return 0;
/* lookup user in passwd */
pw = getpwnam(username);
if (pw == NULL)
{
(void)fprintf(stderr, LOGPREFIX "Unable to get user \"%s\" from passwd!: %m\n", username);
return 0;
}
/* check parent */
if (!check_parent(username))
return 0;
/* seteuid */
if (seteuid(pw->pw_uid))
{
(void)fprintf(stderr, LOGPREFIX "Unable to call seteuid for user \"%s\": %m\n", username);
return 0;
}
if (pw->pw_dir == NULL)
{
(void)fprintf(stderr, LOGPREFIX "User \"%s\" has no homedir?\n", username);
return 0;
}
num = snprintf(path, sizeof(path), "%s/" MAILDIR_NAME "/" MAILDIRSIZE_FILENAME, pw->pw_dir);
if (num < 0 || num > sizeof(path))
{
(void)fprintf(stderr, LOGPREFIX "Unable to copy maildir string to buffer for user \"%s\".\n", username);
return 0;
}
if (maildir_file_read(path, buf, sizeof(buf) - 1) <= 0)
return 0;
quota.file = path;
quota.total_bytes = quota.total_count = 0;
if (!maildir_file_parse("a, buf))
return 0;
if ((quota.bytes_limit != 0 && quota.total_bytes > quota.bytes_limit) ||
(quota.count_limit != 0 && quota.total_count > quota.count_limit))
{
(void)fprintf(stderr, LOGPREFIX "User \"%s\" is over quota.\n", username);
(void)printf("E553 User over quota. (#5.1.1)\n");
}
return 0;
}