nom version : 7.1.3 and also main at the time of creating the issue.
nom compilation features used: default features only
Test case
fn main() {
let _ = nom::bytes::complete::tag_no_case::<_,_,nom::error::Error<&str>>("k")("K");
}
The tag_no_case function can panic whenever a character in a to be matched string lowercases to a character with a shorter byte pattern.
In the above example the K to be matched is actually the kelvin sign with the UTF-8 byte pattern of 0xE2 0x84 0xAA. This character has a the normal single byte k as its lowercase character and therefore matches the tag.
This assumes that the length in bytes of the matched characters is the same as the tag it was matched to. But, as in the above example, this is not always the case, resulting in the function sometimes trying to split a string outside of a character boundary and panicking
1.75.0Test case
The
tag_no_casefunction can panic whenever a character in a to be matched string lowercases to a character with a shorter byte pattern.In the above example the K to be matched is actually the kelvin sign with the UTF-8 byte pattern of
0xE2 0x84 0xAA. This character has a the normal single byte k as its lowercase character and therefore matches the tag.The
tag_no_caseimplementation, after matching a string to the tag, splits the given string with the length of the tag: https://github.com/rust-bakery/nom/blob/e87c7da9fa2ddb943306369f6c6d9e914256edbc/src/bytes/mod.rs#L76This assumes that the length in bytes of the matched characters is the same as the tag it was matched to. But, as in the above example, this is not always the case, resulting in the function sometimes trying to split a string outside of a character boundary and panicking