1 /* $NetBSD: quote_822_local.c,v 1.3 2022/10/08 16:12:45 christos Exp $ */
2
3 /*++
4 /* NAME
5 /* quote_822_local 3
6 /* SUMMARY
7 /* quote local part of mailbox
8 /* SYNOPSIS
9 /* #include <quote_822_local.h>
10 /*
11 /* VSTRING *quote_822_local(dst, src)
12 /* VSTRING *dst;
13 /* const char *src;
14 /*
15 /* VSTRING *quote_822_local_flags(dst, src, flags)
16 /* VSTRING *dst;
17 /* const char *src;
18 /* int flags;
19 /*
20 /* VSTRING *unquote_822_local(dst, src)
21 /* VSTRING *dst;
22 /* const char *src;
23 /* DESCRIPTION
24 /* quote_822_local() quotes the local part of a mailbox and
25 /* returns a result that can be used in message headers as
26 /* specified by RFC 822 (actually, an 8-bit clean version of
27 /* RFC 822). It implements an 8-bit clean version of RFC 822.
28 /*
29 /* quote_822_local_flags() provides finer control.
30 /*
31 /* unquote_822_local() transforms the local part of a mailbox
32 /* address to unquoted (internal) form.
33 /*
34 /* Arguments:
35 /* .IP dst
36 /* The result.
37 /* .IP src
38 /* The input address.
39 /* .IP flags
40 /* Bit-wise OR of zero or more of the following.
41 /* .RS
42 /* .IP QUOTE_FLAG_8BITCLEAN
43 /* In violation with RFCs, treat 8-bit text as ordinary text.
44 /* .IP QUOTE_FLAG_EXPOSE_AT
45 /* In violation with RFCs, treat `@' as an ordinary character.
46 /* .IP QUOTE_FLAG_APPEND
47 /* Append to the result buffer, instead of overwriting it.
48 /* .IP QUOTE_FLAG_BARE_LOCALPART
49 /* The input is a localpart without @domain part.
50 /* .RE
51 /* STANDARDS
52 /* RFC 822 (ARPA Internet Text Messages)
53 /* BUGS
54 /* The code assumes that the domain is RFC 822 clean.
55 /* LICENSE
56 /* .ad
57 /* .fi
58 /* The Secure Mailer license must be distributed with this software.
59 /* AUTHOR(S)
60 /* Wietse Venema
61 /* IBM T.J. Watson Research
62 /* P.O. Box 704
63 /* Yorktown Heights, NY 10598, USA
64 /*
65 /* Wietse Venema
66 /* Google, Inc.
67 /* 111 8th Avenue
68 /* New York, NY 10011, USA
69 /*--*/
70
71 /* System library. */
72
73 #include <sys_defs.h>
74 #include <string.h>
75 #include <ctype.h>
76
77 /* Utility library. */
78
79 #include <vstring.h>
80
81 /* Global library. */
82
83 /* Application-specific. */
84
85 #include "quote_822_local.h"
86
87 /* Local stuff. */
88
89 #define YES 1
90 #define NO 0
91
92 /* is_822_dot_string - is this local-part an rfc 822 dot-string? */
93
is_822_dot_string(const char * local_part,const char * end,int flags)94 static int is_822_dot_string(const char *local_part, const char *end, int flags)
95 {
96 const char *cp;
97 int ch;
98
99 /*
100 * Detect any deviations from a sequence of atoms separated by dots. We
101 * could use lookup tables to speed up some of the work, but hey, how
102 * large can a local-part be anyway?
103 *
104 * RFC 822 expects 7-bit data. Rather than quoting every 8-bit character
105 * (and still passing it on as 8-bit data) we leave 8-bit data alone.
106 */
107 if (local_part == end || local_part[0] == 0 || local_part[0] == '.')
108 return (NO);
109 for (cp = local_part; cp < end && (ch = *(unsigned char *) cp) != 0; cp++) {
110 if (ch == '.' && (cp + 1) < end && cp[1] == '.')
111 return (NO);
112 if (ch > 127 && !(flags & QUOTE_FLAG_8BITCLEAN))
113 return (NO);
114 if (ch == ' ')
115 return (NO);
116 if (ISCNTRL(ch))
117 return (NO);
118 if (ch == '(' || ch == ')'
119 || ch == '<' || ch == '>'
120 || (ch == '@' && !(flags & QUOTE_FLAG_EXPOSE_AT)) || ch == ','
121 || ch == ';' || ch == ':'
122 || ch == '\\' || ch == '"'
123 || ch == '[' || ch == ']')
124 return (NO);
125 }
126 if (cp[-1] == '.')
127 return (NO);
128 return (YES);
129 }
130
131 /* make_822_quoted_string - make quoted-string from local-part */
132
make_822_quoted_string(VSTRING * dst,const char * local_part,const char * end,int flags)133 static VSTRING *make_822_quoted_string(VSTRING *dst, const char *local_part,
134 const char *end, int flags)
135 {
136 const char *cp;
137 int ch;
138
139 /*
140 * Put quotes around the result, and prepend a backslash to characters
141 * that need quoting when they occur in a quoted-string.
142 */
143 VSTRING_ADDCH(dst, '"');
144 for (cp = local_part; cp < end && (ch = *(unsigned char *) cp) != 0; cp++) {
145 if ((ch > 127 && !(flags & QUOTE_FLAG_8BITCLEAN))
146 || ch == '"' || ch == '\\' || ch == '\r')
147 VSTRING_ADDCH(dst, '\\');
148 VSTRING_ADDCH(dst, ch);
149 }
150 VSTRING_ADDCH(dst, '"');
151 return (dst);
152 }
153
154 /* quote_822_local_flags - quote local part of mailbox according to rfc 822 */
155
quote_822_local_flags(VSTRING * dst,const char * mbox,int flags)156 VSTRING *quote_822_local_flags(VSTRING *dst, const char *mbox, int flags)
157 {
158 const char *start; /* first byte of localpart */
159 const char *end; /* first byte after localpart */
160 const char *colon;
161
162 /*
163 * According to RFC 822, a local-part is a dot-string or a quoted-string.
164 * We first see if the local-part is a dot-string. If it is not, we turn
165 * it into a quoted-string. Anything else would be too painful. But
166 * first, skip over any source route that precedes the local-part.
167 */
168 if (mbox[0] == '@' && (colon = strchr(mbox, ':')) != 0)
169 start = colon + 1;
170 else
171 start = mbox;
172 if ((flags & QUOTE_FLAG_BARE_LOCALPART) != 0
173 || (end = strrchr(start, '@')) == 0)
174 end = start + strlen(start);
175 if ((flags & QUOTE_FLAG_APPEND) == 0)
176 VSTRING_RESET(dst);
177 if (is_822_dot_string(start, end, flags)) {
178 return (vstring_strcat(dst, mbox));
179 } else {
180 vstring_strncat(dst, mbox, start - mbox);
181 make_822_quoted_string(dst, start, end, flags & QUOTE_FLAG_8BITCLEAN);
182 return (vstring_strcat(dst, end));
183 }
184 }
185
186 /* unquote_822_local - unquote local part of mailbox according to rfc 822 */
187
unquote_822_local(VSTRING * dst,const char * mbox)188 VSTRING *unquote_822_local(VSTRING *dst, const char *mbox)
189 {
190 const char *start; /* first byte of localpart */
191 const char *colon;
192 const char *cp;
193 int in_quote = 0;
194 const char *bare_at_src;
195 int bare_at_dst_pos = -1;
196
197 /* Don't unquote a routing prefix. Is this still possible? */
198 if (mbox[0] == '@' && (colon = strchr(mbox, ':')) != 0) {
199 start = colon + 1;
200 vstring_strncpy(dst, mbox, start - mbox);
201 } else {
202 start = mbox;
203 VSTRING_RESET(dst);
204 }
205 /* Locate the last unquoted '@'. */
206 for (cp = start; *cp; cp++) {
207 if (*cp == '"') {
208 in_quote = !in_quote;
209 continue;
210 } else if (*cp == '@') {
211 if (!in_quote) {
212 bare_at_dst_pos = VSTRING_LEN(dst);
213 bare_at_src = cp;
214 }
215 } else if (*cp == '\\') {
216 if (cp[1] == 0)
217 continue;
218 cp++;
219 }
220 VSTRING_ADDCH(dst, *cp);
221 }
222 /* Don't unquote text after the last unquoted '@'. */
223 if (bare_at_dst_pos >= 0) {
224 vstring_truncate(dst, bare_at_dst_pos);
225 vstring_strcat(dst, bare_at_src);
226 } else
227 VSTRING_TERMINATE(dst);
228 return (dst);
229 }
230
231 #ifdef TEST
232
233 /*
234 * Proof-of-concept test program. Read an unquoted address from stdin, and
235 * show the quoted and unquoted results. Specify <> to test behavior for an
236 * empty unquoted address.
237 */
238 #include <ctype.h>
239 #include <string.h>
240
241 #include <msg.h>
242 #include <name_mask.h>
243 #include <stringops.h>
244 #include <vstream.h>
245 #include <vstring_vstream.h>
246
247 #define STR vstring_str
248
main(int unused_argc,char ** argv)249 int main(int unused_argc, char **argv)
250 {
251 VSTRING *in = vstring_alloc(100);
252 VSTRING *out = vstring_alloc(100);
253 char *cmd;
254 char *bp;
255 int flags;
256
257 while (vstring_fgets_nonl(in, VSTREAM_IN)) {
258 bp = STR(in);
259 if ((cmd = mystrtok(&bp, CHARS_SPACE)) != 0) {
260 while (ISSPACE(*bp))
261 bp++;
262 if (*bp == 0) {
263 msg_warn("missing argument");
264 continue;
265 }
266 if (strcmp(bp, "<>") == 0)
267 bp = "";
268 if (strcmp(cmd, "quote") == 0) {
269 quote_822_local(out, bp);
270 vstream_printf("'%s' quoted '%s'\n", bp, STR(out));
271 } else if (strcmp(cmd, "quote_with_flags") == 0) {
272 if ((cmd = mystrtok(&bp, CHARS_SPACE)) == 0) {
273 msg_warn("missing flags");
274 continue;
275 }
276 while (ISSPACE(*bp))
277 bp++;
278 flags = quote_flags_from_string(cmd);
279 quote_822_local_flags(out, bp, flags);
280 vstream_printf("'%s' quoted flags=%s '%s'\n",
281 bp, quote_flags_to_string((VSTRING *) 0, flags), STR(out));
282 } else if (strcmp(cmd, "unquote") == 0) {
283 unquote_822_local(out, bp);
284 vstream_printf("'%s' unquoted '%s'\n", bp, STR(out));
285 } else {
286 msg_warn("unknown command: %s", cmd);
287 }
288 vstream_fflush(VSTREAM_OUT);
289 }
290 }
291 vstring_free(in);
292 vstring_free(out);
293 return (0);
294 }
295
296 #endif
297