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use base64::Engine;
use nom::{
branch::alt,
bytes::complete::{tag, tag_no_case, take, take_while, take_while1},
character::complete::{tab, u16, u64},
combinator::{map, opt, recognize, rest, value},
error::{Error, ErrorKind},
multi::{many1, separated_list0},
sequence::{pair, preceded, tuple},
IResult,
};
use super::types::*;
pub fn client_command<'a>(input: &'a [u8]) -> IResult<&'a [u8], ClientCommand> {
alt((version_command, cpid_command, auth_command, cont_command))(input)
}
/*
fn server_command(buf: &u8) -> IResult<&u8, ServerCommand> {
unimplemented!();
}
*/
// ---------------------
fn version_command<'a>(input: &'a [u8]) -> IResult<&'a [u8], ClientCommand> {
let mut parser = tuple((tag_no_case(b"VERSION"), tab, u64, tab, u64));
let (input, (_, _, major, _, minor)) = parser(input)?;
Ok((input, ClientCommand::Version(Version { major, minor })))
}
pub fn cpid_command<'a>(input: &'a [u8]) -> IResult<&'a [u8], ClientCommand> {
preceded(
pair(tag_no_case(b"CPID"), tab),
map(u64, |v| ClientCommand::Cpid(v)),
)(input)
}
fn mechanism<'a>(input: &'a [u8]) -> IResult<&'a [u8], Mechanism> {
alt((
value(Mechanism::Plain, tag_no_case(b"PLAIN")),
value(Mechanism::Login, tag_no_case(b"LOGIN")),
))(input)
}
fn is_not_tab_or_esc_or_lf(c: u8) -> bool {
c != 0x09 && c != 0x01 && c != 0x0a // TAB or 0x01 or LF
}
fn is_esc<'a>(input: &'a [u8]) -> IResult<&'a [u8], &[u8]> {
preceded(tag(&[0x01]), take(1usize))(input)
}
fn parameter<'a>(input: &'a [u8]) -> IResult<&'a [u8], &[u8]> {
recognize(many1(alt((take_while1(is_not_tab_or_esc_or_lf), is_esc))))(input)
}
fn parameter_str(input: &[u8]) -> IResult<&[u8], String> {
let (input, buf) = parameter(input)?;
std::str::from_utf8(buf)
.map(|v| (input, v.to_string()))
.map_err(|_| nom::Err::Failure(Error::new(input, ErrorKind::TakeWhile1)))
}
fn is_param_name_char(c: u8) -> bool {
is_not_tab_or_esc_or_lf(c) && c != 0x3d // =
}
fn parameter_name(input: &[u8]) -> IResult<&[u8], String> {
let (input, buf) = take_while1(is_param_name_char)(input)?;
std::str::from_utf8(buf)
.map(|v| (input, v.to_string()))
.map_err(|_| nom::Err::Failure(Error::new(input, ErrorKind::TakeWhile1)))
}
fn service<'a>(input: &'a [u8]) -> IResult<&'a [u8], String> {
preceded(tag_no_case("service="), parameter_str)(input)
}
fn auth_option<'a>(input: &'a [u8]) -> IResult<&'a [u8], AuthOption> {
use AuthOption::*;
alt((
alt((
value(Debug, tag_no_case(b"debug")),
value(NoPenalty, tag_no_case(b"no-penalty")),
value(ClientId, tag_no_case(b"client_id")),
value(NoLogin, tag_no_case(b"nologin")),
map(preceded(tag_no_case(b"session="), u64), |id| Session(id)),
map(preceded(tag_no_case(b"lip="), parameter_str), |ip| {
LocalIp(ip)
}),
map(preceded(tag_no_case(b"rip="), parameter_str), |ip| {
RemoteIp(ip)
}),
map(preceded(tag_no_case(b"lport="), u16), |port| {
LocalPort(port)
}),
map(preceded(tag_no_case(b"rport="), u16), |port| {
RemotePort(port)
}),
map(preceded(tag_no_case(b"real_rip="), parameter_str), |ip| {
RealRemoteIp(ip)
}),
map(preceded(tag_no_case(b"real_lip="), parameter_str), |ip| {
RealLocalIp(ip)
}),
map(preceded(tag_no_case(b"real_lport="), u16), |port| {
RealLocalPort(port)
}),
map(preceded(tag_no_case(b"real_rport="), u16), |port| {
RealRemotePort(port)
}),
)),
alt((
map(
preceded(tag_no_case(b"local_name="), parameter_str),
|name| LocalName(name),
),
map(
preceded(tag_no_case(b"forward_views="), parameter),
|views| ForwardViews(views.into()),
),
map(preceded(tag_no_case(b"secured="), parameter_str), |info| {
Secured(Some(info))
}),
value(Secured(None), tag_no_case(b"secured")),
value(CertUsername, tag_no_case(b"cert_username")),
map(preceded(tag_no_case(b"transport="), parameter_str), |ts| {
Transport(ts)
}),
map(
preceded(tag_no_case(b"tls_cipher="), parameter_str),
|cipher| TlsCipher(cipher),
),
map(
preceded(tag_no_case(b"tls_cipher_bits="), parameter_str),
|bits| TlsCipherBits(bits),
),
map(preceded(tag_no_case(b"tls_pfs="), parameter_str), |pfs| {
TlsPfs(pfs)
}),
map(
preceded(tag_no_case(b"tls_protocol="), parameter_str),
|proto| TlsProtocol(proto),
),
map(
preceded(tag_no_case(b"valid-client-cert="), parameter_str),
|cert| ValidClientCert(cert),
),
)),
alt((
map(preceded(tag_no_case(b"resp="), base64), |data| Resp(data)),
map(
tuple((parameter_name, tag(b"="), parameter)),
|(n, _, v)| UnknownPair(n, v.into()),
),
map(parameter, |v| UnknownBool(v.into())),
)),
))(input)
}
fn auth_command<'a>(input: &'a [u8]) -> IResult<&'a [u8], ClientCommand> {
let mut parser = tuple((
tag_no_case(b"AUTH"),
tab,
u64,
tab,
mechanism,
tab,
service,
map(opt(preceded(tab, separated_list0(tab, auth_option))), |o| {
o.unwrap_or(vec![])
}),
));
let (input, (_, _, id, _, mech, _, service, options)) = parser(input)?;
Ok((
input,
ClientCommand::Auth {
id,
mech,
service,
options,
},
))
}
fn is_base64_core(c: u8) -> bool {
c >= 0x30 && c <= 0x39 // 0-9
|| c >= 0x41 && c <= 0x5a // A-Z
|| c >= 0x61 && c <= 0x7a // a-z
|| c == 0x2b // +
|| c == 0x2f // /
}
fn is_base64_pad(c: u8) -> bool {
c == 0x3d // =
}
fn base64(input: &[u8]) -> IResult<&[u8], Vec<u8>> {
let (input, (b64, _)) = tuple((take_while1(is_base64_core), take_while(is_base64_pad)))(input)?;
let data = base64::engine::general_purpose::STANDARD_NO_PAD
.decode(b64)
.map_err(|_| nom::Err::Failure(Error::new(input, ErrorKind::TakeWhile1)))?;
Ok((input, data))
}
/// @FIXME Dovecot does not say if base64 content must be padded or not
fn cont_command<'a>(input: &'a [u8]) -> IResult<&'a [u8], ClientCommand> {
let mut parser = tuple((tag_no_case(b"CONT"), tab, u64, tab, base64));
let (input, (_, _, id, _, data)) = parser(input)?;
Ok((input, ClientCommand::Cont { id, data }))
}
// -----------------------------------------------------------------
//
// SASL DECODING
//
// -----------------------------------------------------------------
fn not_null(c: u8) -> bool {
c != 0x0
}
// impersonated user, login, password
pub fn auth_plain<'a>(input: &'a [u8]) -> IResult<&'a [u8], (&'a [u8], &'a [u8], &'a [u8])> {
map(
tuple((
take_while(not_null),
take(1usize),
take_while(not_null),
take(1usize),
rest,
)),
|(imp, _, user, _, pass)| (imp, user, pass),
)(input)
}
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