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/*
* debsig-verify - Debian package signature verification tool
*
* Copyright © 2000 Ben Collins <bcollins@debian.org>
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/*
* provides the XML parsing code for policy files, via expat (xmltok)
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <sys/stat.h>
#include <obstack.h>
#include <xmltok/xmlparse.h>
#include "debsig.h"
#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free
static int parse_err_cnt;
static struct policy ret;
static struct group *cur_grp = NULL;
static XML_Parser parser;
static struct obstack deb_obs;
static int deb_obs_init = 0;
#define parse_error(fmt, args...) \
{ \
parse_err_cnt++; \
ds_printf(DS_LEV_DEBUG , "%d: " fmt , XML_GetCurrentLineNumber(parser) , ## args); \
}
static void *xmalloc(size_t size) {
register void *p = malloc(size);
if (p == NULL)
ds_fail_printf(DS_FAIL_INTERNAL, "out of memory");
return p;
}
static void startElement(void *userData, const char *name, const char **atts) {
int i, depth;
int *depthPtr = userData;
/* save the current and increment the userdata */
depth = *depthPtr;
*depthPtr = depth + 1;
if (!strcmp(name,"Policy")) {
if (depth != 0)
parse_error("policy parse error: 'Policy' found at wrong level");
for (i = 0; atts[i]; i += 2) {
if (!strcmp(atts[i], "xmlns")) {
if (strcmp(atts[i + 1], DEBSIG_NAMESPACE))
parse_error("policy name space != " DEBSIG_NAMESPACE);
} else
parse_error("Policy element contains unknown attribute '%s'",
atts[i]);
}
} else if (!strcmp(name,"Origin")) {
if (depth != 1)
parse_error("policy parse error: 'Origin' found at wrong level");
for (i = 0; atts[i]; i += 2) {
if (!strcmp(atts[i], "id"))
ret.id = obstack_copy0(&deb_obs, atts[i+1], strlen(atts[i+1]));
else if (!strcmp(atts[i], "Name"))
ret.name = obstack_copy0(&deb_obs, atts[i+1], strlen(atts[i+1]));
else if (!strcmp(atts[i], "Description"))
ret.description = obstack_copy0(&deb_obs, atts[i+1], strlen(atts[i+1]));
else
parse_error("Origin element contains unknown attribute '%s'",
atts[i]);
}
if (ret.id == NULL || ret.name == NULL)
parse_error("Origin element missing Name or ID attribute");
} else if (!strcmp(name,"Selection") || !strcmp(name,"Verification")) {
struct group *g = NULL;
if (depth != 1)
parse_error("policy parse error: 'Selection/Verification' found at wrong level");
/* create a new entry, make it the current */
cur_grp = (struct group *)obstack_alloc(&deb_obs, sizeof(struct group));
if (cur_grp == NULL)
ds_fail_printf(DS_FAIL_INTERNAL, "out of memory");
memset(cur_grp, 0, sizeof(struct group));
if (!strcmp(name,"Selection")) {
if (ret.sels == NULL)
ret.sels = cur_grp;
else
g = ret.sels;
} else {
if (ret.vers == NULL)
ret.vers = cur_grp;
else
g = ret.vers;
}
if (g) {
for ( ; g->next; g = g->next)
; /* find the end of the chain */
g->next = cur_grp;
}
for (i = 0; atts[i]; i += 2) {
if (!strcmp(atts[i], "MinOptional")) {
int t; const char *c = atts[i+1];
for (t = 0; c[t]; t++) {
if (!isdigit(c[t]))
parse_error("MinOptional requires a numerical value");
}
cur_grp->min_opt = atoi(c);
} else {
parse_error("Selection/Verification element contains unknown attribute '%s'",
atts[i]);
}
}
} else if (!strcmp(name,"Required") || !strcmp(name,"Reject") ||
!strcmp(name,"Optional")) {
struct match *m = NULL, *cur_m = NULL;
if (depth != 2)
parse_error("policy parse error: Match element found at wrong level");
/* This should never happen with the other checks in place */
if (cur_grp == NULL) {
parse_error("policy parse error: No current group for match element");
return;
}
/* create a new entry, make it the current */
cur_m = (struct match *)obstack_alloc(&deb_obs, sizeof(struct match));
if (cur_m == NULL)
ds_fail_printf(DS_FAIL_INTERNAL, "out of memory");
memset(cur_m, 0, sizeof(struct match));
if (cur_grp->matches == NULL)
cur_grp->matches = cur_m;
else {
for (m = cur_grp->matches; m->next; m = m->next)
; /* find the end of the chain */
m->next = cur_m;
}
/* Set the attributes first, so we can sanity check the type after */
for (i = 0; atts[i]; i += 2) {
if (!strcmp(atts[i], "Type")) {
cur_m->name = obstack_copy0(&deb_obs, atts[i+1], strlen(atts[i+1]));
} else if (!strcmp(atts[i], "File")) {
cur_m->file = obstack_copy0(&deb_obs, atts[i+1], strlen(atts[i+1]));;
} else if (!strcmp(atts[i], "id")) {
cur_m->id = obstack_copy0(&deb_obs, atts[i+1], strlen(atts[i+1]));;
} else if (!strcmp(atts[i], "Expiry")) {
int t; const char *c = atts[i+1];
for (t = 0; c[t]; t++) {
if (!isdigit(c[t]))
parse_error("Expiry requires a numerical value");
}
cur_m->day_expiry = atoi(c);
} else {
parse_error("Match element contains unknown attribute '%s'",
atts[i]);
}
}
if (!strcmp(name,"Required")) {
cur_m->type = REQUIRED_MATCH;
if (cur_m->name == NULL || cur_m->file == NULL)
parse_error("Required must have a Type and File attribute");
} else if (!strcmp(name,"Optional")) {
cur_m->type = OPTIONAL_MATCH;
if (cur_m->name == NULL || cur_m->file == NULL)
parse_error("Optional must have a Type and File attribute");
} else { /* Reject */
cur_m->type = REJECT_MATCH;
if (cur_m->name == NULL)
parse_error("Reject must have a Type attribute");
}
}
}
static void endElement(void *userData, const char *name) {
int *depthPtr = userData;
*depthPtr -= 1;
if (!strcmp(name,"Selection") || !strcmp(name,"Verification")) {
struct match *m; int i = 0;
/* sanity check this block */
for (m = cur_grp->matches; m; m = m->next) {
if (m->type == OPTIONAL_MATCH ||
m->type == REQUIRED_MATCH)
i++;
}
if (!i) {
parse_error("Selection/Verification block does not contain any "
"Required or Optional matches.");
}
cur_grp = NULL; /* just to make sure */
}
}
void clear_policy(void) {
if (deb_obs_init) {
obstack_free(&deb_obs, 0);
deb_obs_init = 0;
}
memset(&ret, '\0', sizeof(struct policy));
return;
}
struct policy *parsePolicyFile(const char *filename) {
char buf[BUFSIZ];
int done, depth = 0;
FILE *pol_fs;
struct stat st;
/* clear and initialize */
parser = XML_ParserCreate(NULL);
//clear_policy();
obstack_init(&deb_obs);
deb_obs_init = 1;
ds_printf(DS_LEV_DEBUG, " parsePolicyFile: parsing '%s'", filename);
if (stat(filename, &st)) {
ds_printf(DS_LEV_ERR, "parsePolicyFile: could not stat %s", filename);
return NULL;
}
if (!S_ISREG(st.st_mode)) {
ds_printf(DS_LEV_ERR, "parsePolicyFile: %s is not a regular file", filename);
return NULL;
}
if ((pol_fs = fopen(filename, "r")) == NULL) {
ds_printf(DS_LEV_ERR, "parsePolicyFile: could not open '%s' (%s)",
filename, strerror(errno));
return NULL;
}
XML_SetUserData(parser, &depth);
XML_SetElementHandler(parser, startElement, endElement);
parse_err_cnt = 0;
do {
size_t len = fread(buf, 1, sizeof(buf), pol_fs);
done = len < sizeof(buf);
if (!XML_Parse(parser, buf, len, done)) {
ds_printf(DS_LEV_DEBUG,
"%s at line %d",
XML_ErrorString(XML_GetErrorCode(parser)),
XML_GetCurrentLineNumber(parser));
parse_err_cnt++;
break;
}
} while (!done);
XML_ParserFree(parser);
fclose(pol_fs);
ds_printf(DS_LEV_DEBUG, " parsePolicyFile: completed");
if (parse_err_cnt) {
ds_printf(DS_LEV_DEBUG, " parsePolicyFile: %d errors during parsing, failed",
parse_err_cnt);
clear_policy();
return NULL;
}
return &ret;
}
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