When using DOUBLE_QUOTED_STRING, passwords with '\"' may not work

[Alan DeKok]

On Sep 10, 2023, at 9:16 PM, 平林 哲 <Satoshi.Hirabayashi at soliton.co.jp> wrote:
> ===
> # cat /usr/local/etc/raddb/mods-enabled/ldap1
> ldap {
>        server = '192.168.1.6'
>        identity = 'cn=tkt10886-3,cn=users,dc=srv2022,dc=rdd-osaka,dc=soliton,dc=example,dc=jp'
>        password = "pass\\"word at 2022"

  Two backslashes.

> However, it behaves differently in the shell.
> 
> ===
> $ echo "pass\\\"word at 2022"

  Three backslashes.

> pass\"word at 2022
> ===

  Use three backslashes with FreeRADIUS, and it will work.

> Maybe the two backslashes need to be escaped into one backslash?

  I explained the rules for double-quoted strings.  They're the same for all double quoted strings in FreeRADIUS, and in the shell.

  If you want a " in the middle of a double quoted string, you have to escape it:  \"

  If you want a \ in the middle of a double quoted string, you have to escape it: \\

  Which means that if you want *both* a " and a \ in a double quoted string, you need to have an *odd* number of backslashes.

  All you need to do is count the number of backslashes.  Even *and* there's a quote in the middle of the string?  Parse error.  Odd number of backslashes?  It's fine.

  Alan DeKok.