馃 Validate ID values contain only valid bytes - #698
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Also update internal RawText docs.
This shares most of the validation implementation with RawText, via an extracted shared superclass. Please note: in currently released `net-imap`, QuotedString is _not_ used to quote regular string arguments. It's currently only used by `Net::IMAP#id` (the `ID` extension). Without this patch, `Net::IMAP#id` is vulnerable to the same CRLF injection issues in GHSA-75xq-5h9v-w6px and GHSA-hm49-wcqc-g2xg. The string will be quoted, which may limit the ability to inject some commands. Presumably, `Net::IMAP#id` is unlikely to be called with user-provided input, making this less likely to be exploitable. Nevertheless, CRLF injection should be prevented!
This removes the duplicated string quoting implementation. It also introduces stricter enforcement of `quoted` string validation..
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This shares most of the validation implementation with RawText, via an extracted shared superclass. Please note: in currently released `net-imap`, QuotedString is _not_ used to quote regular string arguments. It's currently only used by `Net::IMAP#id` (the `ID` extension). Without this patch, `Net::IMAP#id` is vulnerable to the same CRLF injection issues in GHSA-75xq-5h9v-w6px and GHSA-hm49-wcqc-g2xg. The string will be quoted, which may limit the ability to inject some commands. Presumably, `Net::IMAP#id` is unlikely to be called with user-provided input, making this less likely to be exploitable. Nevertheless, CRLF injection should be prevented!
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This bug was introduced by a742a10. When I extracted the `UNQUOTABLE_CHARS` regexp into a constant, I didn't copied it exactly. It was converted from a character class into a sequence of bytes: ```ruby # It should've been this: UNQUOTABLE_CHARS = /[\0\r\n]/n # But I incorrectly copied it as this: UNQUOTABLE_CHARS = /\0\r\n/n ``` If that regexp were the only guard, this regexp would've allowed CRLF injections! Fortunately, quoted strings are now sent using `Net::IMAP::QuotedString` (since #698, released in v0.6.4.1), and that _does_ correctly validate that the input is a valid quoted string. So, the string isn't _sent_ as invalid quoted data. Unfortunately, this does result in an exception for strings that could be valid literals. And, because it crashes while sending command arguments, rather than during validation, the connection will be broken.
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This shares most of the validation implementation with
RawText, via an extracted shared superclass.In currently released versions of
net-imap,QuotedStringis not used to quote regular string arguments. It's currently only used byNet::IMAP#id(theIDextension). This PR reverses the dependency, so thatsend_string_datacallsQuotedString, rather than vice versa.Without this patch,
Net::IMAP#idis vulnerable to the same type of CRLF injection issues as in CVE-2026-42258 (GHSA-75xq-5h9v-w6px) and CVE-2026-42257 (GHSA-hm49-wcqc-g2xg). The string will be quoted, which imposes some limits on what command arguments can be injected, but many destructive commands will work fine without any quoted specials.Presumably,
Net::IMAP#idshould be very unlikely to be called with untrusted input, making this less likely to be exploitable. Nevertheless, CRLF injection should be prevented!