1 /* vi: set sw=4 ts=4: */
3 * Check user and group names for illegal characters
5 * Copyright (C) 2008 Tito Ragusa <farmatito@tiscali.it>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
11 /* To avoid problems, the username should consist only of
12 * letters, digits, underscores, periods, at signs and dashes,
13 * and not start with a dash (as defined by IEEE Std 1003.1-2001).
14 * For compatibility with Samba machine accounts $ is also supported
15 * at the end of the username.
18 void FAST_FUNC die_if_bad_username(const char *name)
20 const char *start = name;
22 /* 1st char being dash or dot isn't valid:
23 * for example, name like ".." can make adduser
24 * chown "/home/.." recursively - NOT GOOD.
25 * Name of just a single "$" is also rejected.
32 /* These chars are valid unless they are at the 1st pos: */
35 /* $ is allowed if it's the last char: */
36 || (*name == '$' && !name[1])
43 /* || ch == '@' -- we disallow this too. Think about "user@host" */
44 /* open-coded isalnum: */
45 || (ch >= '0' && ch <= '9')
46 || ((ch|0x20) >= 'a' && (ch|0x20) <= 'z')
50 bb_error_msg_and_die("illegal character with code %u at position %u",
51 (unsigned)ch, (unsigned)(name - start));
54 /* The minimum size of the login name is one char or two if
55 * last char is the '$'. Violations of this are caught above.
56 * The maximum size of the login name is LOGIN_NAME_MAX
57 * including the terminating null byte.
59 if (name - start >= LOGIN_NAME_MAX)
60 bb_error_msg_and_die("name is too long");