Problem - Kevin Tafuro

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102 | Chapter 3: Input Validation
Keep in mind that almost any character is legal in an email address if it
is properly quoted, so if you are passing an email address to something
that may be sensitive to certain characters or character sequences
(such as a command shell), you must be sure to properly escape those
characters.
int spc_email_isvalid(const char *address) {
int count = 0;
const char *c, *domain;
static char *rfc822_specials = "()@,;:\\\"[]";
/* first we validate the name portion (name@domain) */
for (c = address; *c; c++) {
if (*c == '\"' && (c == address || *(c - 1) == '.' || *(c - 1) ==
'\"')) {
while (*++c) {
if (*c == '\"') break;
if (*c == '\\' && (*++c == ' ')) continue;
if (*c = 127) return 0;
}
if (!*c++) return 0;
if (*c == '@') break;
if (*c != '.') return 0;
continue;
}
if (*c == '@') break;
if (*c = 127) return 0;
if (strchr(rfc822_specials, *c)) return 0;
}
if (c == address || *(c - 1) == '.') return 0;
/* next we validate the domain portion (name@domain) */
if (!*(domain = ++c)) return 0;
do {
if (*c == '.') {
if (c == domain || *(c - 1) == '.') return 0;
count++;
}
if (*c = 127) return 0;
if (strchr(rfc822_specials, *c)) return 0;
} while (*++c);
return (count >= 1);
}
See Also
RFC 822: Standard for the Format of ARPA Internet Text Messages
This is the Title of the Book, eMatter Edition
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