Harden plaintext authenticator

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index c53a392a4fb4e6eadc0fe078d18c665598944d6a..0bce6fe86135e14b33572c7c5f6aa8db1c29447e 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -6745,6 +6745,11 @@ lookup types support only literal keys.
 &*Warning 2*&: In a host list, you must always use &(net-iplsearch)& so that
 the implicit key is the host's IP address rather than its name (see section
 &<<SECThoslispatsikey>>&).
+
+.new
+&*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the
+IPv4.  Such addresses being searched for are converted to IPv4.
+.wen
 .next
 .cindex "linear search"
 .cindex "lookup" "lsearch"
@@ -8663,8 +8668,12 @@ to quote keys was made available in &(lsearch)& files. However, the more
 recently implemented &(iplsearch)& files do require colons in IPv6 keys
 (notated using the quoting facility) so as to distinguish them from IPv4 keys.
 For this reason, when the lookup type is &(iplsearch)&, IPv6 addresses are
-converted using colons and not dots. In all cases, full, unabbreviated IPv6
+converted using colons and not dots.
+.new
+In all cases except IPv4-mapped IPv6, full, unabbreviated IPv6
 addresses are always used.
+The latter are converted to IPv4 addresses, in dotted-quad form.
+.wen
 
 Ideally, it would be nice to tidy up this anomalous situation by changing to
 colons in all cases, given that quoting is now available for &(lsearch)&.
@@ -9537,6 +9546,8 @@ The expanded <&'string1'&> must be of the form:
 The braces, commas and colons, and the quoting of the member name are required;
 the spaces are optional.
 Matching of the key against the member names is done case-sensitively.
+If a returned value is a JSON string, it retains its leading and
+trailing quotes.
 . XXX should be a UTF-8 compare
 
 The results of matching are handled as above.
@@ -9584,6 +9595,8 @@ apart from leading and trailing white space, which is ignored.
 
 Field selection and result handling is as above;
 there is no choice of field separator.
+If a returned value is a JSON string, it retains its leading and
+trailing quotes.
 .wen
 
 
@@ -23581,7 +23594,8 @@ command = /bin/sh -c ${lookup{$local_part}lsearch{/some/file}}
 .cindex "filter" "transport filter"
 .vindex "&$pipe_addresses$&"
 Special handling takes place when an argument consists of precisely the text
-&`$pipe_addresses`&. This is not a general expansion variable; the only
+&`$pipe_addresses`& (no quotes).
+This is not a general expansion variable; the only
 place this string is recognized is when it appears as an argument for a pipe or
 transport filter command. It causes each address that is being handled to be
 inserted in the argument list at that point &'as a separate argument'&. This
@@ -39430,8 +39444,9 @@ Signers MUST use RSA keys of at least 1024 bits for all keys.
 Signers SHOULD use RSA keys of at least 2048 bits.
 .endd
 
-Support for EC keys is being developed under
-&url(https://datatracker.ietf.org/doc/draft-ietf-dcrup-dkim-crypto/).
+.new
+EC keys for DKIM are defined by RFC 8463.
+.wen
 They are considerably smaller than RSA keys for equivalent protection.
 As they are a recent development, users should consider dual-signing
 (by setting a list of selectors, and an expansion for this option)
@@ -39451,10 +39466,12 @@ openssl pkey -outform DER -pubout -in dkim_ed25519.private | tail -c +13 | base6
 certtool --load_privkey=dkim_ed25519.private --pubkey_info --outder | tail -c +13 | base64
 .endd
 
-Note that the format
-of Ed25519 keys in DNS has not yet been decided; this release supports
-both of the leading candidates at this time, a future release will
-probably drop support for whichever proposal loses.
+.new
+Exim also supports an alternate format
+of Ed25519 keys in DNS which was a candidate during development
+of the standard, but not adopted.
+A future release will probably drop that support.
+.wen
 
 .option dkim_hash smtp string&!! sha256
 Can be set to any one of the supported hash methods, which are: