There's is_valid_user_name():
alx@debian:~/src/shadow/shadow/wextra$ grepc -ntfd is_valid_user_name src/ lib*
lib/chkname.c:75:
bool is_valid_user_name (const char *name)
{
size_t maxlen;
/*
* User names length are limited by the kernel
*/
maxlen = sysconf(_SC_LOGIN_NAME_MAX);
if (strlen(name) > maxlen)
return false;
return is_valid_name (name);
}Which limits the length of a valid user name by sysconf(_SC_LOGIN_NAME_MAX). But it calls is_valid_name():
alx@debian:~/src/shadow/shadow/wextra$ grepc -ntfd is_valid_name src/ lib*
lib/chkname.c:28:
static bool is_valid_name (const char *name)
{
if (allow_bad_names) {
return true;
}
/*
* User/group names must match gnu e-regex:
* [a-zA-Z0-9_.][a-zA-Z0-9_.-]{0,30}[a-zA-Z0-9_.$-]?
*
* as a non-POSIX, extension, allow "$" as the last char for
* sake of Samba 3.x "add machine script"
*
* Also do not allow fully numeric names or just "." or "..".
*/
int numeric;
if ('\0' == *name ||
('.' == *name && (('.' == name[1] && '\0' == name[2]) ||
'\0' == name[1])) ||
!((*name >= 'a' && *name <= 'z') ||
(*name >= 'A' && *name <= 'Z') ||
(*name >= '0' && *name <= '9') ||
*name == '_' ||
*name == '.')) {
return false;
}
numeric = isdigit(*name);
while ('\0' != *++name) {
if (!((*name >= 'a' && *name <= 'z') ||
(*name >= 'A' && *name <= 'Z') ||
(*name >= '0' && *name <= '9') ||
*name == '_' ||
*name == '.' ||
*name == '-' ||
(*name == '$' && name[1] == '\0')
)) {
return false;
}
numeric &= isdigit(*name);
}
return !numeric;
}Which in a comment, says the name should match a regex that allows no more than 32 characters. I don't see the code actually enforcing that regex, as the loop seems unlimited. So, I have some questions:
- Should we be limiting valid user names to 32 characters?
- Or should we change that regex to specify what the code is really doing?
Or am I missing something?
Cc: @ikerexxe This was triggered by your suggestion of writing tests for this function. :)
There's
is_valid_user_name():Which limits the length of a valid user name by
sysconf(_SC_LOGIN_NAME_MAX). But it callsis_valid_name():Which in a comment, says the name should match a regex that allows no more than 32 characters. I don't see the code actually enforcing that regex, as the loop seems unlimited. So, I have some questions:
Or am I missing something?
Cc: @ikerexxe This was triggered by your suggestion of writing tests for this function. :)