d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Modify mountd.c so that it does not always malloc 4K for the map credentials.

Browse Source 
r362163 upgraded mountd so that it could handle MAX_NGROUPS
groups for the anonymous user credentials (the ones provided by
-maproot and -mapall exports options).
The problem is that this resulted in every export structure growing by
about 4Kbytes, because the cr_groups field went from 16->MAX_NGROUPS.

This patch fixes this by only including a small 32 element cr_groups in the
structure and then malloc()'ng cr_groups when a larger one is needed.
The value of SMALLNGROUPS is arbitrarily set to 32, assuming most users
used by -maproot or -mapall will be in <= 32 groups.

Reviewed by:	kib, freqlabs
Differential Revision:	https://reviews.freebsd.org/D26521
This commit is contained in:
Rick Macklem 2020-10-10 00:01:40 +00:00
parent c2c6fb90e0
commit 2ffad162f3
1 changed files with 44 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
usr.sbin/mountd/mountd.c
View File

@ -115,11 +115,15 @@ struct dirlist {
/*
* maproot/mapall credentials.
* cr_smallgrps can be used for a group list up to SMALLNGROUPS in size.
* Larger group lists are malloc'd/free'd.
*/
#define SMALLNGROUPS 32
struct expcred {
uid_t cr_uid;
int cr_ngroups;
gid_t cr_groups[NGROUPS_MAX + 1];
gid_t cr_smallgrps[SMALLNGROUPS];
gid_t *cr_groups;
};
struct exportlist {
@ -1514,6 +1518,7 @@ get_exportlist_one(int passno)
uint64_t exflags;
v4root_phase = 0;
anon.cr_groups = NULL;
dirhead = (struct dirlist *)NULL;
while (get_line()) {
if (debug)
@ -1527,6 +1532,7 @@ get_exportlist_one(int passno)
* Set defaults.
*/
has_host = FALSE;
anon.cr_groups = anon.cr_smallgrps;
anon.cr_uid = UID_NOBODY;
anon.cr_ngroups = 1;
anon.cr_groups[0] = GID_NOGROUP;
@ -1822,6 +1828,10 @@ nextline:
free_dir(dirhead);
dirhead = (struct dirlist *)NULL;
}
if (anon.cr_groups != anon.cr_smallgrps) {
free(anon.cr_groups);
anon.cr_groups = NULL;
}
}
}
@ -2905,6 +2915,8 @@ free_exp(struct exportlist *ep)
grp = grp->gr_next;
free_grp(tgrp);
}
if (ep->ex_defanon.cr_groups != ep->ex_defanon.cr_smallgrps)
free(ep->ex_defanon.cr_groups);
free((caddr_t)ep);
}
@ -3457,14 +3469,17 @@ static void
parsecred(char *namelist, struct expcred *cr)
{
char *name;
int cnt;
int inpos;
char *names;
struct passwd *pw;
struct group *gr;
gid_t groups[NGROUPS_MAX + 1];
int ngroups;
/*
* Set up the unprivileged user.
*/
cr->cr_groups = cr->cr_smallgrps;
cr->cr_uid = UID_NOBODY;
cr->cr_groups[0] = GID_NOGROUP;
cr->cr_ngroups = 1;
@ -3487,24 +3502,28 @@ parsecred(char *namelist, struct expcred *cr)
return;
}
cr->cr_uid = pw->pw_uid;
cr->cr_ngroups = NGROUPS_MAX + 1;
if (getgrouplist(pw->pw_name, pw->pw_gid, cr->cr_groups,
&cr->cr_ngroups)) {
ngroups = NGROUPS_MAX + 1;
if (getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups)) {
syslog(LOG_ERR, "too many groups");
cr->cr_ngroups = NGROUPS_MAX + 1;
ngroups = NGROUPS_MAX + 1;
}
/*
* Compress out duplicate.
*/
if (cr->cr_ngroups > 1 && cr->cr_groups[0] ==
cr->cr_groups[1]) {
for (cnt = 2; cnt < cr->cr_ngroups; cnt++)
cr->cr_groups[cnt - 1] = cr->cr_groups[cnt];
cr->cr_ngroups--;
}
if (cr->cr_ngroups > NGROUPS_MAX)
cr->cr_ngroups = NGROUPS_MAX;
if (ngroups > 1 && groups[0] == groups[1]) {
ngroups--;
inpos = 2;
} else
inpos = 1;
if (ngroups > NGROUPS_MAX)
ngroups = NGROUPS_MAX;
if (ngroups > SMALLNGROUPS)
cr->cr_groups = malloc(ngroups * sizeof(gid_t));
cr->cr_ngroups = ngroups;
cr->cr_groups[0] = groups[0];
memcpy(&cr->cr_groups[1], &groups[inpos], (ngroups - 1) *
sizeof(gid_t));
return;
}
/*
@ -3523,17 +3542,20 @@ parsecred(char *namelist, struct expcred *cr)
while (names != NULL && *names != '\0' && cr->cr_ngroups < NGROUPS_MAX) {
name = strsep_quote(&names, ":");
if (isdigit(*name) || *name == '-') {
cr->cr_groups[cr->cr_ngroups++] = atoi(name);
groups[cr->cr_ngroups++] = atoi(name);
} else {
if ((gr = getgrnam(name)) == NULL) {
syslog(LOG_ERR, "unknown group: %s", name);
continue;
}
cr->cr_groups[cr->cr_ngroups++] = gr->gr_gid;
groups[cr->cr_ngroups++] = gr->gr_gid;
}
}
if (names != NULL && *names != '\0' && cr->cr_ngroups == NGROUPS_MAX)
syslog(LOG_ERR, "too many groups");
if (cr->cr_ngroups > SMALLNGROUPS)
cr->cr_groups = malloc(cr->cr_ngroups * sizeof(gid_t));
memcpy(cr->cr_groups, groups, cr->cr_ngroups * sizeof(gid_t));
}
#define STRSIZ (MNTNAMLEN+MNTPATHLEN+50)
@ -3642,6 +3664,8 @@ free_grp(struct grouplist *grp)
if (grp->gr_ptr.gt_net.nt_name)
free(grp->gr_ptr.gt_net.nt_name);
}
if (grp->gr_anon.cr_groups != grp->gr_anon.cr_smallgrps)
free(grp->gr_anon.cr_groups);
free((caddr_t)grp);
}
@ -3860,6 +3884,10 @@ cp_cred(struct expcred *outcr, struct expcred *incr)
outcr->cr_uid = incr->cr_uid;
outcr->cr_ngroups = incr->cr_ngroups;
if (outcr->cr_ngroups > SMALLNGROUPS)
outcr->cr_groups = malloc(outcr->cr_ngroups * sizeof(gid_t));
else
outcr->cr_groups = outcr->cr_smallgrps;
memcpy(outcr->cr_groups, incr->cr_groups, incr->cr_ngroups *
sizeof(gid_t));
}