bin/83696: Maximum members in group seems broken

[Jeff Stelzner]

>Number:         83696
>Category:       bin
>Synopsis:       Maximum members in group seems broken
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Jul 18 23:40:15 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Jeff Stelzner
>Release:        5.4-RELEASE
>Organization:
AREVA T&D
>Environment:
%uname -a
FreeBSD probe.support.esca.com 5.4-RELEASE FreeBSD 5.4-RELEASE #0: Sun May  8 10:21:06 UTC 2005 root at harlow.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
Per group (5) there was a historical limit of 200 members per group and 1024 characters per line in /etc/group, both of which are no longer supposed to exist.

Looking at the output of '/usr/bin/id -Gn' however:
- A test group containing 97 [or fewer] members works OK [member list length 371]
- A test group containing 128 [or more] members is broken [member list length 499]

This is a problem on systems using group-based access control where the groups need to contain a significant number of member user accounts. It appears that the limits to both [a] number of members and [b] line length are either broken or incorrectly documented.


>How-To-Repeat:
Create test groups in /etc/group that contain increasing numbers of members, including a single test account 'xyz'. From the 'xyz' account run 'id -Gn' to determine whether the account is or is not a member of the groups. Obviously you don't want to exceed the NGROUPS system limit.

Here's the setup on my test box:
# grep xyz /etc/passwd
xyz:*:1002:1002:freebsd-5.4 group test::0:0:/home/xyz:/bin/csh
# su - xyz
%grep xyz /etc/group
grp32:*:6664:g0,g1,g2,g3,g4,g5,g6,g7,g8,g9,ga,gb,gc,gd,ge,gf,g10,g11,g12,g13,g14
,g15,g16,g17,g18,g19,g1a,g1b,g1c,g1d,g1e,g1f,xyz
grp64:*:6665:g0,g1,g2,g3,g4,g5,g6,g7,g8,g9,ga,gb,gc,gd,ge,gf,g10,g11,g12,g13,g14
,g15,g16,g17,g18,g19,g1a,g1b,g1c,g1d,g1e,g1f,g20,g21,g22,g23,g24,g25,g26,g27,g28
,g29,g2a,g2b,g2c,g2d,g2e,g2f,g30,g31,g32,g33,g34,g35,g36,g37,g38,g39,g3a,g3b,g3c
,g3d,g3e,g3f,xyz
grp96:*:6666:g0,g1,g2,g3,g4,g5,g6,g7,g8,g9,ga,gb,gc,gd,ge,gf,g10,g11,g12,g13,g14
,g15,g16,g17,g18,g19,g1a,g1b,g1c,g1d,g1e,g1f,g20,g21,g22,g23,g24,g25,g26,g27,g28
,g29,g2a,g2b,g2c,g2d,g2e,g2f,g30,g31,g32,g33,g34,g35,g36,g37,g38,g39,g3a,g3b,g3c
,g3d,g3e,g3f,g40,g41,g42,g43,g44,g45,g46,g47,g48,g49,g4a,g4b,g4c,g4d,g4e,g4f,g50
,g51,g52,g53,g54,g55,g56,g57,g58,g59,g5a,g5b,g5c,g5d,g5e,g5f,xyz
grp128:*:6667:g0,g1,g2,g3,g4,g5,g6,g7,g8,g9,ga,gb,gc,gd,ge,gf,g10,g11,g12,g13,g1
4,g15,g16,g17,g18,g19,g1a,g1b,g1c,g1d,g1e,g1f,g20,g21,g22,g23,g24,g25,g26,g27,g2
8,g29,g2a,g2b,g2c,g2d,g2e,g2f,g30,g31,g32,g33,g34,g35,g36,g37,g38,g39,g3a,g3b,g3
c,g3d,g3e,g3f,g40,g41,g42,g43,g44,g45,g46,g47,g48,g49,g4a,g4b,g4c,g4d,g4e,g4f,g5
0,g51,g52,g53,g54,g55,g56,g57,g58,g59,g5a,g5b,g5c,g5d,g5e,g5f,g60,g61,g62,g63,g6
4,g65,g66,g67,g68,g69,g6a,g6b,g6c,g6d,g6e,g6f,g70,g71,g72,g73,g74,g75,g76,g77,g7
8,g79,g7a,g7b,g7c,g7d,g7e,g7f,xyz
grp256:*:6668:g0,g1,g2,g3,g4,g5,g6,g7,g8,g9,ga,gb,gc,gd,ge,gf,g10,g11,g12,g13,g1
4,g15,g16,g17,g18,g19,g1a,g1b,g1c,g1d,g1e,g1f,g20,g21,g22,g23,g24,g25,g26,g27,g2
8,g29,g2a,g2b,g2c,g2d,g2e,g2f,g30,g31,g32,g33,g34,g35,g36,g37,g38,g39,g3a,g3b,g3
c,g3d,g3e,g3f,g40,g41,g42,g43,g44,g45,g46,g47,g48,g49,g4a,g4b,g4c,g4d,g4e,g4f,g5
0,g51,g52,g53,g54,g55,g56,g57,g58,g59,g5a,g5b,g5c,g5d,g5e,g5f,g60,g61,g62,g63,g6
4,g65,g66,g67,g68,g69,g6a,g6b,g6c,g6d,g6e,g6f,g70,g71,g72,g73,g74,g75,g76,g77,g7
8,g79,g7a,g7b,g7c,g7d,g7e,g7f,g80,g81,g82,g83,g84,g85,g86,g87,g88,g89,g8a,g8b,g8
c,g8d,g8e,g8f,g90,g91,g92,g93,g94,g95,g96,g97,g98,g99,g9a,g9b,g9c,g9d,g9e,g9f,ga
0,ga1,ga2,ga3,ga4,ga5,ga6,ga7,ga8,ga9,gaa,gab,gac,gad,gae,gaf,gb0,gb1,gb2,gb3,gb
4,gb5,gb6,gb7,gb8,gb9,gba,gbb,gbc,gbd,gbe,gbf,gc0,gc1,gc2,gc3,gc4,gc5,gc6,gc7,gc
8,gc9,gca,gcb,gcc,gcd,gce,gcf,gd0,gd1,gd2,gd3,gd4,gd5,gd6,gd7,gd8,gd9,gda,gdb,gd
c,gdd,gde,gdf,ge0,ge1,ge2,ge3,ge4,ge5,ge6,ge7,ge8,ge9,gea,geb,gec,ged,gee,gef,gf
0,gf1,gf2,gf3,gf4,gf5,gf6,gf7,gf8,gf9,gfa,gfb,gfc,gfd,gfe,gff,xyz
xyz:*:1002:
%/usr/bin/id -Gn
xyz grp32 grp64 grp96
%


>Fix:
      
>Release-Note:
>Audit-Trail:
>Unformatted: