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In preparation for raising NGROUPS and NGROUPS_MAX, change base

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system callers of getgroups(), getgrouplist(), and setgroups() to
allocate buffers dynamically.  Specifically, allocate a buffer of size
sysconf(_SC_NGROUPS_MAX)+1 (+2 in a few cases to allow for overflow).

This (or similar gymnastics) is required for the code to actually follow
the POSIX.1-2008 specification where {NGROUPS_MAX} may differ at runtime
and where getgroups may return {NGROUPS_MAX}+1 results on systems like
FreeBSD which include the primary group.

In id(1), don't pointlessly add the primary group to the list of all
groups, it is always the first result from getgroups().  In principle
the old code was more portable, but this was only done in one of the two
places where getgroups() was called to the overall effect was pointless.

Document the actual POSIX requirements in the getgroups(2) and
setgroups(2) manpages.  We do not yet support a dynamic NGROUPS, but we
may in the future.

MFC after:	2 weeks
This commit is contained in:
Brooks Davis 2009-06-19 15:58:24 +00:00
parent 68cc62cec1
commit 54404cfb13
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=194494
13 changed files with 109 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
lib/libc/gen/initgroups.3
View File

@ -65,6 +65,13 @@ function may fail and set
.Va errno
for any of the errors specified for the library function
.Xr setgroups 2 .
It may also return:
.Bl -tag -width Er
.It Bq Er ENOMEM
The
.Fn initgroups
function was unable to allocate temporary storage.
.El
.Sh SEE ALSO
.Xr setgroups 2 ,
.Xr getgrouplist 3

21
lib/libc/gen/initgroups.c
View File

@ -35,10 +35,12 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <stdio.h>
#include "namespace.h"
#include <err.h>
#include "un-namespace.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int
@ -46,14 +48,21 @@ initgroups(uname, agroup)
const char *uname;
gid_t agroup;
{
int ngroups;
int ngroups, ret;
long ngroups_max;
gid_t *groups;
/*
* Provide space for one group more than NGROUPS to allow
* Provide space for one group more than possible to allow
* setgroups to fail and set errno.
*/
gid_t groups[NGROUPS + 1];
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 2;
if ((groups = malloc(sizeof(*groups) * ngroups_max)) == NULL)
return (ENOMEM);
ngroups = NGROUPS + 1;
ngroups = (int)ngroups_max;
getgrouplist(uname, agroup, groups, &ngroups);
return (setgroups(ngroups, groups));
ret = setgroups(ngroups, groups);
free(groups);
return (ret);
}

18
lib/libc/rpc/auth_unix.c
View File

@ -185,23 +185,29 @@ authunix_create(machname, uid, gid, len, aup_gids)
AUTH *
authunix_create_default()
{
int len;
int ngids;
long ngids_max;
char machname[MAXHOSTNAMELEN + 1];
uid_t uid;
gid_t gid;
gid_t gids[NGROUPS_MAX];
gid_t *gids;
ngids_max = sysconf(_SC_NGROUPS_MAX) + 1;
gids = malloc(sizeof(gid_t) * ngids_max);
if (gids == NULL)
return (NULL);
if (gethostname(machname, sizeof machname) == -1)
abort();
machname[sizeof(machname) - 1] = 0;
uid = geteuid();
gid = getegid();
if ((len = getgroups(NGROUPS_MAX, gids)) < 0)
if ((ngids = getgroups(ngids_max, gids)) < 0)
abort();
if (len > NGRPS)
len = NGRPS;
if (ngids > NGRPS)
ngids = NGRPS;
/* XXX: interface problem; those should all have been unsigned */
return (authunix_create(machname, (int)uid, (int)gid, len,
return (authunix_create(machname, (int)uid, (int)gid, ngids,
(int *)gids));
}

10
lib/libc/sys/getgroups.2
View File

@ -58,10 +58,7 @@ The
system call
returns the actual number of groups returned in
.Fa gidset .
No more than
.Dv NGROUPS_MAX
will ever
be returned.
At least one and as many as {NGROUPS_MAX}+1 values may be returned.
If
.Fa gidsetlen
is zero,
@ -92,6 +89,11 @@ an invalid address.
.Sh SEE ALSO
.Xr setgroups 2 ,
.Xr initgroups 3
.Sh STANDARDS
The
.Fn getgroups
system call conforms to
.St -p1003.1-2008 .
.Sh HISTORY
The
.Fn getgroups

6
lib/libc/sys/setgroups.2
View File

@ -53,9 +53,7 @@ The
argument
indicates the number of entries in the array and must be no
more than
.Dv NGROUPS ,
as defined in
.In sys/param.h .
.Dv {NGROUPS_MAX}+1 .
.Pp
Only the super-user may set a new group list.
.Sh RETURN VALUES
@ -71,7 +69,7 @@ The caller is not the super-user.
The number specified in the
.Fa ngroups
argument is larger than the
.Dv NGROUPS
.Dv {NGROUPS_MAX}+1
limit.
.It Bq Er EFAULT
The address specified for

25
usr.bin/id/id.c
View File

@ -258,7 +258,8 @@ id_print(struct passwd *pw, int use_ggl, int p_euid, int p_egid)
gid_t gid, egid, lastgid;
uid_t uid, euid;
int cnt, ngroups;
gid_t groups[NGROUPS + 1];
long ngroups_max;
gid_t *groups;
const char *fmt;
if (pw != NULL) {
@ -270,12 +271,16 @@ id_print(struct passwd *pw, int use_ggl, int p_euid, int p_egid)
gid = getgid();
}
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
if (use_ggl && pw != NULL) {
ngroups = NGROUPS + 1;
ngroups = ngroups_max;
getgrouplist(pw->pw_name, gid, groups, &ngroups);
}
else {
ngroups = getgroups(NGROUPS + 1, groups);
ngroups = getgroups(ngroups_max, groups);
}
if (pw != NULL)
@ -306,6 +311,7 @@ id_print(struct passwd *pw, int use_ggl, int p_euid, int p_egid)
lastgid = gid;
}
printf("\n");
free(groups);
}
#ifdef USE_BSM_AUDIT
@ -361,15 +367,19 @@ group(struct passwd *pw, int nflag)
{
struct group *gr;
int cnt, id, lastid, ngroups;
gid_t groups[NGROUPS + 1];
long ngroups_max;
gid_t *groups;
const char *fmt;
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * (ngroups_max))) == NULL)
err(1, "malloc");
if (pw) {
ngroups = NGROUPS + 1;
ngroups = ngroups_max;
(void) getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
} else {
groups[0] = getgid();
ngroups = getgroups(NGROUPS, groups + 1) + 1;
ngroups = getgroups(ngroups_max, groups);
}
fmt = nflag ? "%s" : "%u";
for (lastid = -1, cnt = 0; cnt < ngroups; ++cnt) {
@ -389,6 +399,7 @@ group(struct passwd *pw, int nflag)
lastid = id;
}
(void)printf("\n");
free(groups);
}
void

12
usr.bin/newgrp/newgrp.c
View File

@ -146,8 +146,8 @@ restoregrps(void)
static void
addgroup(const char *grpname)
{
gid_t grps[NGROUPS_MAX];
long lgid;
gid_t *grps;
long lgid, ngrps_max;
int dbmember, i, ngrps;
gid_t egid;
struct group *grp;
@ -185,7 +185,10 @@ addgroup(const char *grpname)
}
}
if ((ngrps = getgroups(NGROUPS_MAX, (gid_t *)grps)) < 0) {
ngrps_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((grps = malloc(sizeof(gid_t) * ngrps_max)) == NULL)
err(1, "malloc");
if ((ngrps = getgroups(ngrps_max, (gid_t *)grps)) < 0) {
warn("getgroups");
return;
}
@ -217,7 +220,7 @@ addgroup(const char *grpname)
/* Add old effective gid to supp. list if it does not exist. */
if (egid != grp->gr_gid && !inarray(egid, grps, ngrps)) {
if (ngrps == NGROUPS_MAX)
if (ngrps == ngrps_max)
warnx("too many groups");
else {
grps[ngrps++] = egid;
@ -231,6 +234,7 @@ addgroup(const char *grpname)
}
}
free(grps);
}
static int

10
usr.bin/quota/quota.c
View File

@ -117,7 +117,8 @@ int
main(int argc, char *argv[])
{
int ngroups;
gid_t mygid, gidset[NGROUPS];
long ngroups_max;
gid_t mygid, *gidset;
int i, ch, gflag = 0, uflag = 0, errflag = 0;
while ((ch = getopt(argc, argv, "f:ghlrquv")) != -1) {
@ -159,13 +160,18 @@ main(int argc, char *argv[])
errflag += showuid(getuid());
if (gflag) {
mygid = getgid();
ngroups = getgroups(NGROUPS, gidset);
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((gidset = malloc(sizeof(gid_t) * ngroups_max))
== NULL)
err(1, "malloc");
ngroups = getgroups(ngroups_max, gidset);
if (ngroups < 0)
err(1, "getgroups");
errflag += showgid(mygid);
for (i = 0; i < ngroups; i++)
if (gidset[i] != mygid)
errflag += showgid(gidset[i]);
free(gidset);
}
return(errflag);
}

8
usr.sbin/chown/chown.c
View File

@ -269,7 +269,8 @@ chownerr(const char *file)
{
static uid_t euid = -1;
static int ngroups = -1;
gid_t groups[NGROUPS_MAX];
static long ngroups_max;
gid_t *groups;
/* Check for chown without being root. */
if (errno != EPERM || (uid != (uid_t)-1 &&
@ -281,7 +282,10 @@ chownerr(const char *file)
/* Check group membership; kernel just returns EPERM. */
if (gid != (gid_t)-1 && ngroups == -1 &&
euid == (uid_t)-1 && (euid = geteuid()) != 0) {
ngroups = getgroups(NGROUPS_MAX, groups);
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
ngroups = getgroups(ngroups_max, groups);
while (--ngroups >= 0 && gid != groups[ngroups]);
if (ngroups < 0) {
warnx("you are not a member of group %s", gname);

10
usr.sbin/chroot/chroot.c
View File

@ -69,9 +69,10 @@ main(argc, argv)
struct passwd *pw;
char *endp, *p;
const char *shell;
gid_t gid, gidlist[NGROUPS_MAX];
gid_t gid, *gidlist;
uid_t uid;
int ch, gids;
long ngroups_max;
gid = 0;
uid = 0;
@ -117,8 +118,11 @@ main(argc, argv)
}
}
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
for (gids = 0;
(p = strsep(&grouplist, ",")) != NULL && gids < NGROUPS_MAX; ) {
(p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) {
if (*p == '\0')
continue;
@ -135,7 +139,7 @@ main(argc, argv)
}
gids++;
}
if (p != NULL && gids == NGROUPS_MAX)
if (p != NULL && gids == ngroups_max)
errx(1, "too many supplementary groups provided");
if (user != NULL) {

9
usr.sbin/jail/jail.c
View File

@ -104,7 +104,7 @@ extern char **environ;
lcap = login_getpwclass(pwd); \
if (lcap == NULL) \
err(1, "getpwclass: %s", username); \
ngroups = NGROUPS; \
ngroups = ngroups_max; \
if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0) \
err(1, "getgrouplist: %s", username); \
} while (0)
@ -115,10 +115,11 @@ main(int argc, char **argv)
login_cap_t *lcap = NULL;
struct iovec rparams[2];
struct passwd *pwd = NULL;
gid_t groups[NGROUPS];
gid_t *groups;
size_t sysvallen;
int ch, cmdarg, i, jail_set_flags, jid, ngroups, sysval;
int hflag, iflag, Jflag, lflag, rflag, uflag, Uflag;
long ngroups_max;
unsigned pi;
char *ep, *jailname, *securelevel, *username, *JidFile;
char errmsg[ERRMSG_SIZE], enforce_statfs[4];
@ -132,6 +133,10 @@ main(int argc, char **argv)
jailname = securelevel = username = JidFile = cleanenv = NULL;
fp = NULL;
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
while ((ch = getopt(argc, argv, "cdhilmn:r:s:u:U:J:")) != -1) {
switch (ch) {
case 'd':

9
usr.sbin/jexec/jexec.c
View File

@ -59,7 +59,7 @@ static void usage(void);
lcap = login_getpwclass(pwd); \
if (lcap == NULL) \
err(1, "getpwclass: %s", username); \
ngroups = NGROUPS; \
ngroups = ngroups_max; \
if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0) \
err(1, "getgrouplist: %s", username); \
} while (0)
@ -71,12 +71,17 @@ main(int argc, char *argv[])
int jid;
login_cap_t *lcap = NULL;
struct passwd *pwd = NULL;
gid_t groups[NGROUPS];
gid_t *groups = NULL;
int ch, ngroups, uflag, Uflag;
long ngroups_max;
char *ep, *username;
ch = uflag = Uflag = 0;
username = NULL;
ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
while ((ch = getopt(argc, argv, "nu:U:")) != -1) {
switch (ch) {
case 'n':

8
usr.sbin/lpr/lpc/lpc.c
View File

@ -356,7 +356,8 @@ ingroup(const char *grname)
{
static struct group *gptr=NULL;
static int ngroups = 0;
static gid_t groups[NGROUPS];
static long ngroups_max;
static gid_t *groups;
register gid_t gid;
register int i;
@ -365,7 +366,10 @@ ingroup(const char *grname)
warnx("warning: unknown group '%s'", grname);
return(0);
}
ngroups = getgroups(NGROUPS, groups);
ngroups_max = sysconf(_SC_NGROUPS_MAX);
if ((groups = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
err(1, "malloc");
ngroups = getgroups(ngroups_max, groups);
if (ngroups < 0)
err(1, "getgroups");
}