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ber: Improved decoding for GeneralizedTime, tests
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@Nicceboy
Nicceboy committed Aug 25, 2023
1 parent 0c4d745 commit 82c87b9
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Showing 2 changed files with 178 additions and 13 deletions.
87 changes: 87 additions & 0 deletions src/ber.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -196,4 +196,91 @@ mod tests {
}
}
}
#[test]
fn test_generalized_time() {
use chrono::{DateTime, FixedOffset, NaiveDate, Utc};
// "20801009130005.342Z"
let offset = chrono::FixedOffset::east_opt(0).unwrap();
let dt = NaiveDate::from_ymd_opt(2080, 10, 9)
.unwrap()
.and_hms_micro_opt(13, 0, 5, 342_000)
.unwrap()
.and_local_timezone(offset);
round_trip!(
ber,
GeneralizedTime,
GeneralizedTime::from(dt.unwrap(),),
&[
0x18, 0x13, 0x32, 0x30, 0x38, 0x30, 0x31, 0x30, 0x30, 0x39, 0x31, 0x33, 0x30, 0x30,
0x30, 0x35, 0x2e, 0x33, 0x34, 0x32, 0x5a
]
);

// https://github.com/XAMPPRocky/rasn/issues/57
let data = [
24, 19, 43, 53, 49, 54, 49, 53, 32, 32, 48, 53, 50, 52, 48, 57, 52, 48, 50, 48, 90,
];
assert!(crate::der::decode::<crate::types::Open>(&data).is_err());
assert!(crate::ber::decode::<crate::types::Open>(&data).is_err());

// "20180122132900Z"
round_trip!(
ber,
GeneralizedTime,
GeneralizedTime::from(
NaiveDate::from_ymd_opt(2018, 1, 22)
.unwrap()
.and_hms_opt(13, 29, 0)
.unwrap()
.and_utc()
),
&[
0x18, 0x0f, 0x32, 0x30, 0x31, 0x38, 0x30, 0x31, 0x32, 0x32, 0x31, 0x33, 0x32, 0x39,
0x30, 0x30, 0x5a
]
);
// "20180122130000Z"
round_trip!(
ber,
GeneralizedTime,
GeneralizedTime::from(
NaiveDate::from_ymd_opt(2018, 1, 22)
.unwrap()
.and_hms_opt(13, 0, 0)
.unwrap()
.and_utc()
),
&[
0x18, 0x0f, 0x32, 0x30, 0x31, 0x38, 0x30, 0x31, 0x32, 0x32, 0x31, 0x33, 0x30, 0x30,
0x30, 0x30, 0x5a
]
);

// "20230122130000-0500" - converts to canonical form "20230122180000Z"
let offset = FixedOffset::east_opt(-3600 * 5).unwrap();
let dt1: DateTime<FixedOffset> = GeneralizedTime::from(DateTime::<Utc>::from(
NaiveDate::from_ymd_opt(2023, 1, 22)
.unwrap()
.and_hms_opt(13, 0, 0)
.unwrap()
.and_local_timezone(offset)
.unwrap(),
));
round_trip!(
ber,
GeneralizedTime,
dt1,
&[
0x18, 0x0f, 0x32, 0x30, 0x32, 0x33, 0x30, 0x31, 0x32, 0x32, 0x31, 0x38, 0x30, 0x30,
0x30, 0x30, 0x5a
]
);
// "20230122130000-0500" as bytes
let data = [
24, 19, 50, 48, 50, 51, 48, 49, 50, 50, 49, 51, 48, 48, 48, 48, 45, 48, 53, 48, 48,
];
let result = crate::ber::decode::<crate::types::GeneralizedTime>(&data);
assert!(result.is_ok());
assert_eq!(dt1, result.unwrap());
}
}
104 changes: 91 additions & 13 deletions src/ber/de.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ use crate::{
},
Decode,
};
use chrono::{DateTime, FixedOffset, NaiveDateTime, Utc};

pub use self::{config::DecoderOptions, error::Error};

Expand Down Expand Up @@ -110,22 +111,95 @@ impl<'input> Decoder<'input> {

Ok(result)
}
pub fn parse_generalized_time_string(
/// Parse any GeneralizedTime string, allowing for any from ASN.1 definition
/// TODO, move to type itself?
pub fn parse_any_generalized_time_string(
string: alloc::string::String,
) -> Result<types::GeneralizedTime, Error> {
// Reference https://obj-sys.com/asn1tutorial/node14.html
// If data contains ., 3 decimal places of seconds are expected
// If data contains explict Z, result is UTC
// If data contains + or -, explicit timezone is given
// If neither Z nor + nor -, purely local time is implied
// Enforce BER restrictions defined in Section 11.7, strictly ignore non-compliant
use chrono::{DateTime, NaiveDateTime, Utc};
let len = string.len();
// Helper function to deal with fractions and without timezone
let parse_without_timezone = |string: &str| -> Result<NaiveDateTime, Error> {
// Handle both decimal cases (dot . and comma , )
let string: &str = &string.replace(",", ".");
if string.contains('.') {
// Use chrono to parse the string every time, since we don't the know the number of decimals places
NaiveDateTime::parse_from_str(string, "%Y%m%d%H%.f")
.or_else(|_| NaiveDateTime::parse_from_str(string, "%Y%m%d%H%M%.f"))
.or_else(|_| NaiveDateTime::parse_from_str(string, "%Y%m%d%H%M%S%.f"))
.map_err(|_| Error::InvalidDate)
} else {
let fmt_string = match string.len() {
8 => "%Y%m%d",
10 => "%Y%m%d%H",
12 => "%Y%m%d%H%M",
14 => "%Y%m%d%H%M%S",
_ => "",
};
match fmt_string.len() {
l if l > 0 => NaiveDateTime::parse_from_str(string, fmt_string)
.map_err(|_| Error::InvalidDate),
_ => Err(Error::InvalidDate),
}
}
};
if string.ends_with('Z') {
let naive = parse_without_timezone(&string[..len - 1])?;
return Ok(DateTime::<Utc>::from_utc(naive, Utc).into());
}
// Check for timezone offset
if len > 5
&& string
.chars()
.nth(len - 5)
.map_or(false, |c| c == '+' || c == '-')
{
let naive = parse_without_timezone(&string[..len - 5])?;
let sign = match string.chars().nth(len - 5) {
Some('+') => 1,
Some('-') => -1,
_ => {
return Err(Error::InvalidDate);
}
};
let offset_hours = string
.chars()
.skip(len - 4)
.take(2)
.collect::<alloc::string::String>()
.parse::<i32>()
.map_err(|_| Error::InvalidDate)?;
let offset_minutes = string
.chars()
.skip(len - 2)
.take(2)
.collect::<alloc::string::String>()
.parse::<i32>()
.map_err(|_| Error::InvalidDate)?;
if offset_hours > 23 || offset_minutes > 59 {
return Err(Error::InvalidDate);
}
let offset = FixedOffset::east_opt(sign * (offset_hours * 3600 + offset_minutes * 60))
.ok_or(Error::InvalidDate)?;
return Ok(DateTime::<FixedOffset>::from_local(naive, offset).into());
}

// Parse without timezone details
let naive = parse_without_timezone(&string)?;
Ok(DateTime::<Utc>::from_utc(naive, Utc).into())
}
/// Enforce CER/DER restrictions defined in Section 11.7, strictly raise error on non-compliant
pub fn parse_canonical_generalized_time_string(
string: alloc::string::String,
) -> Result<types::GeneralizedTime, Error> {
let len = string.len();
// Helper function to deal with fractions of seconds and without timezone
let parse_without_timezone = |string: &str| -> core::result::Result<NaiveDateTime, Error> {
let len = string.len();
// Handle both decimal cases (dot . and comma , ), while we don't need to
// let string: &str = &string.replace(",", ".");
if string.contains('.') {
// https://github.com/chronotope/chrono/issues/238#issuecomment-378737786
NaiveDateTime::parse_from_str(string, "%Y%m%d%H%M%S%.f")
Expand All @@ -134,19 +208,19 @@ impl<'input> Decoder<'input> {
NaiveDateTime::parse_from_str(string, "%Y%m%d%H%M%S")
.map_err(|_| Error::InvalidDate)
} else {
// Ber encoding rules don't allow for timezone offset +/
// CER/DER encoding rules don't allow for timezone offset +/
// Or missing seconds/minutes/hours
// Or comma , instead of dot .
// Or local time without timezone
Err(Error::InvalidDate)
}
};
if string.ends_with('Z') {
return if string.ends_with('Z') {
let naive = parse_without_timezone(&string[..len - 1])?;
return Ok(DateTime::<Utc>::from_utc(naive, Utc).into());
}
// Parse without timezone details
let naive = parse_without_timezone(&string)?;
Ok(DateTime::<Utc>::from_utc(naive, Utc).into())
Ok(DateTime::<Utc>::from_utc(naive, Utc).into())
} else {
Err(Error::InvalidDate)
};
}
}

Expand Down Expand Up @@ -392,7 +466,11 @@ impl<'input> crate::Decoder for Decoder<'input> {

fn decode_generalized_time(&mut self, tag: Tag) -> Result<types::GeneralizedTime> {
let string = self.decode_utf8_string(tag, <_>::default())?;
Self::parse_generalized_time_string(string)
if self.config.encoding_rules.is_ber() {
Self::parse_any_generalized_time_string(string)
} else {
Self::parse_canonical_generalized_time_string(string)
}
}

fn decode_utc_time(&mut self, tag: Tag) -> Result<types::UtcTime> {
Expand Down

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