1/*
2 * This file contains helper functions for labeling support.
3 *
4 * Author : Richard Haines <richard_c_haines@btinternet.com>
5 */
6
7#include <stdlib.h>
8#include <stdarg.h>
9#include <ctype.h>
10#include <string.h>
11#include <stdio.h>
12#include <errno.h>
13#include <errno.h>
14#include "label_internal.h"
15
16/*
17 * Read an entry from a spec file (e.g. file_contexts)
18 * entry - Buffer to allocate for the entry.
19 * ptr - current location of the line to be processed.
20 * returns  - 0 on success and *entry is set to be a null
21 *            terminated value. On Error it returns -1 and
22 *            errno will be set.
23 *
24 */
25static inline int read_spec_entry(char **entry, char **ptr, int *len, const char **errbuf)
26{
27	*entry = NULL;
28	char *tmp_buf = NULL;
29
30	while (isspace(**ptr) && **ptr != '\0')
31		(*ptr)++;
32
33	tmp_buf = *ptr;
34	*len = 0;
35
36	while (!isspace(**ptr) && **ptr != '\0') {
37		if (!isascii(**ptr)) {
38			errno = EINVAL;
39			*errbuf = "Non-ASCII characters found";
40			return -1;
41		}
42		(*ptr)++;
43		(*len)++;
44	}
45
46	if (*len) {
47		*entry = strndup(tmp_buf, *len);
48		if (!*entry)
49			return -1;
50	}
51
52	return 0;
53}
54
55/*
56 * line_buf - Buffer containing the spec entries .
57 * errbuf   - Double pointer used for passing back specific error messages.
58 * num_args - The number of spec parameter entries to process.
59 * ...      - A 'char **spec_entry' for each parameter.
60 * returns  - The number of items processed. On error, it returns -1 with errno
61 *            set and may set errbuf to a specific error message.
62 *
63 * This function calls read_spec_entry() to do the actual string processing.
64 * As such, can return anything from that function as well.
65 */
66int  read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...)
67{
68	char **spec_entry, *buf_p;
69	int len, rc, items, entry_len = 0;
70	va_list ap;
71
72	*errbuf = NULL;
73
74	len = strlen(line_buf);
75	if (line_buf[len - 1] == '\n')
76		line_buf[len - 1] = '\0';
77	else
78		/* Handle case if line not \n terminated by bumping
79		 * the len for the check below (as the line is NUL
80		 * terminated by getline(3)) */
81		len++;
82
83	buf_p = line_buf;
84	while (isspace(*buf_p))
85		buf_p++;
86
87	/* Skip comment lines and empty lines. */
88	if (*buf_p == '#' || *buf_p == '\0')
89		return 0;
90
91	/* Process the spec file entries */
92	va_start(ap, num_args);
93
94	items = 0;
95	while (items < num_args) {
96		spec_entry = va_arg(ap, char **);
97
98		if (len - 1 == buf_p - line_buf) {
99			va_end(ap);
100			return items;
101		}
102
103		rc = read_spec_entry(spec_entry, &buf_p, &entry_len, errbuf);
104		if (rc < 0) {
105			va_end(ap);
106			return rc;
107		}
108		if (entry_len)
109			items++;
110	}
111	va_end(ap);
112	return items;
113}
114
115/* Once all the specfiles are in the hash_buf, generate the hash. */
116void  digest_gen_hash(struct selabel_digest *digest)
117{
118	Sha1Context context;
119	size_t remaining_size;
120	const unsigned char *ptr;
121
122	/* If SELABEL_OPT_DIGEST not set then just return */
123	if (!digest)
124		return;
125
126	Sha1Initialise(&context);
127
128	/* Process in blocks of UINT32_MAX bytes */
129	remaining_size = digest->hashbuf_size;
130	ptr = digest->hashbuf;
131	while (remaining_size > UINT32_MAX) {
132		Sha1Update(&context, ptr, UINT32_MAX);
133		remaining_size -= UINT32_MAX;
134		ptr += UINT32_MAX;
135	}
136	Sha1Update(&context, ptr, remaining_size);
137
138	Sha1Finalise(&context, (SHA1_HASH *)digest->digest);
139	free(digest->hashbuf);
140	digest->hashbuf = NULL;
141	return;
142}
143
144/**
145 * digest_add_specfile - Add a specfile to the hashbuf and if gen_hash true
146 *			 then generate the hash.
147 * @digest: pointer to the selabel_digest struct
148 * @fp: file pointer for fread(3) or NULL if not.
149 * @from_addr: pointer at start of buffer for memcpy or NULL if not (used for
150 *	       mmap(3) files).
151 * @buf_len: length of buffer to copy.
152 * @path: pointer to the specfile.
153 *
154 * Return %0 on success, -%1 with @errno set on failure.
155 */
156int  digest_add_specfile(struct selabel_digest *digest, FILE *fp,
157				    char *from_addr, size_t buf_len,
158				    const char *path)
159{
160	unsigned char *tmp_buf;
161
162	/* If SELABEL_OPT_DIGEST not set then just return */
163	if (!digest)
164		return 0;
165
166	if (digest->hashbuf_size + buf_len < digest->hashbuf_size) {
167		errno = EOVERFLOW;
168		return -1;
169	}
170	digest->hashbuf_size += buf_len;
171
172	tmp_buf = realloc(digest->hashbuf, digest->hashbuf_size);
173	if (!tmp_buf)
174		return -1;
175
176	digest->hashbuf = tmp_buf;
177
178	if (fp) {
179		rewind(fp);
180		if (fread(digest->hashbuf + (digest->hashbuf_size - buf_len),
181					    1, buf_len, fp) != buf_len)
182			return -1;
183
184		rewind(fp);
185	} else if (from_addr) {
186		tmp_buf = memcpy(digest->hashbuf +
187				    (digest->hashbuf_size - buf_len),
188				    from_addr, buf_len);
189		if (!tmp_buf)
190			return -1;
191	}
192	/* Now add path to list */
193	digest->specfile_list[digest->specfile_cnt] = strdup(path);
194	if (!digest->specfile_list[digest->specfile_cnt])
195		return -1;
196
197	digest->specfile_cnt++;
198	if (digest->specfile_cnt > DIGEST_FILES_MAX) {
199		errno = EOVERFLOW;
200		return -1;
201	}
202
203	return 0;
204}
205