Обсуждение: Remove one use of IDENT_USERNAME_MAX
It seems to me that using IDENT_USERNAME_MAX for peer authentication is some kind of historical leftover and not really appropriate or useful, so I propose the attached cleanup. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
Вложения
Hello. At Sat, 26 Oct 2019 08:55:03 +0200, Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote in > IDENT_USERNAME_MAX is the maximum length of the information returned > by an ident server, per RFC 1413. Using it as the buffer size in peer > authentication is inappropriate. It was done here because of the > historical relationship between peer and ident authentication. But > since it's also completely useless code-wise, remove it. In think one of the reasons for the coding is the fact that *pw is described to be placed in the static area, which can be overwritten by succeeding calls to getpw*() functions. I think we can believe check_usermap() never calls them but I suppose that some comments needed.. regards. -- Kyotaro Horiguchi NTT Open Source Software Center
Kyotaro Horiguchi <horikyota.ntt@gmail.com> writes: > At Sat, 26 Oct 2019 08:55:03 +0200, Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote in >> IDENT_USERNAME_MAX is the maximum length of the information returned >> by an ident server, per RFC 1413. Using it as the buffer size in peer >> authentication is inappropriate. It was done here because of the >> historical relationship between peer and ident authentication. But >> since it's also completely useless code-wise, remove it. > In think one of the reasons for the coding is the fact that *pw is > described to be placed in the static area, which can be overwritten by > succeeding calls to getpw*() functions. Good point ... so maybe pstrdup instead of using a fixed-size buffer? regards, tom lane
On 2019-10-28 14:45, Tom Lane wrote: > Kyotaro Horiguchi <horikyota.ntt@gmail.com> writes: >> At Sat, 26 Oct 2019 08:55:03 +0200, Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote in >>> IDENT_USERNAME_MAX is the maximum length of the information returned >>> by an ident server, per RFC 1413. Using it as the buffer size in peer >>> authentication is inappropriate. It was done here because of the >>> historical relationship between peer and ident authentication. But >>> since it's also completely useless code-wise, remove it. > >> In think one of the reasons for the coding is the fact that *pw is >> described to be placed in the static area, which can be overwritten by >> succeeding calls to getpw*() functions. > > Good point ... so maybe pstrdup instead of using a fixed-size buffer? Maybe. Or we just decide that check_usermap() is not allowed to call getpw*(). It's just a string-matching routine, so it doesn't have any such business anyway. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes: > On 2019-10-28 14:45, Tom Lane wrote: >> Kyotaro Horiguchi <horikyota.ntt@gmail.com> writes: >>> In think one of the reasons for the coding is the fact that *pw is >>> described to be placed in the static area, which can be overwritten by >>> succeeding calls to getpw*() functions. >> Good point ... so maybe pstrdup instead of using a fixed-size buffer? > Maybe. Or we just decide that check_usermap() is not allowed to call > getpw*(). It's just a string-matching routine, so it doesn't have any > such business anyway. I'm okay with that as long as you add a comment describing this assumption. regards, tom lane
On 2019-10-29 15:34, Tom Lane wrote: > Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes: >> On 2019-10-28 14:45, Tom Lane wrote: >>> Kyotaro Horiguchi <horikyota.ntt@gmail.com> writes: >>>> In think one of the reasons for the coding is the fact that *pw is >>>> described to be placed in the static area, which can be overwritten by >>>> succeeding calls to getpw*() functions. > >>> Good point ... so maybe pstrdup instead of using a fixed-size buffer? > >> Maybe. Or we just decide that check_usermap() is not allowed to call >> getpw*(). It's just a string-matching routine, so it doesn't have any >> such business anyway. > > I'm okay with that as long as you add a comment describing this > assumption. Committed with a pstrdup(). That seemed more consistent with other code in that file. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services