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fix chroot and default user behavior 

Use of chroot causes complications when a root is specified; chroot requires
/etc/^(passwd group) and friends be copied to the new root. This is
uneccessary, and is obviated by use of a new function named rootpath.

Files created with a default user are owned by the user of the process rather
than the default user. This is addressed by issuing a chown after create to
reinstate proper permission.
This commit is contained in:
Steven Stallion 2015-03-16 17:27:33 -05:00
parent fe3a886a1c
commit e5eb212843
1 changed files with 86 additions and 33 deletions
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119
u9fs.c
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@ -12,6 +12,7 @@
#include <errno.h> /* for errno */ #include <errno.h> /* for errno */
#include <stdio.h> /* for remove [sic] */ #include <stdio.h> /* for remove [sic] */
#include <fcntl.h> /* for O_RDONLY, etc. */ #include <fcntl.h> /* for O_RDONLY, etc. */
#include <limits.h> /* for PATH_MAX */
#include <sys/socket.h> /* various networking crud */ #include <sys/socket.h> /* various networking crud */
#include <netinet/in.h> #include <netinet/in.h>
@ -147,6 +148,7 @@ int chatty9p = 0;
int network = 1; int network = 1;
int old9p = -1; int old9p = -1;
int authed; int authed;
char* root;
User* none; User* none;
Auth *authmethods[] = { /* first is default */ Auth *authmethods[] = { /* first is default */
@ -171,6 +173,17 @@ char isfrog[256]={
[0x7f] 1, [0x7f] 1,
}; };
char*
rootpath(char *path)
{
static char buf[PATH_MAX];
if(root == nil)
return path;
snprintf(buf, sizeof buf, "%s%s", root, path);
return buf;
}
void void
getfcallnew(int fd, Fcall *fc, int have) getfcallnew(int fd, Fcall *fc, int have)
{ {
@ -702,7 +715,7 @@ stat2dir(char *path, struct stat *st, Dir *d)
void void
rread(Fcall *rx, Fcall *tx) rread(Fcall *rx, Fcall *tx)
{ {
char *e, *path; char *e, *path, *rpath;
uchar *p, *ep; uchar *p, *ep;
int n; int n;
Fid *fid; Fid *fid;
@ -762,7 +775,8 @@ rread(Fcall *rx, Fcall *tx)
fid->dirent = nil; fid->dirent = nil;
continue; continue;
} }
path = estrpath(fid->path, fid->dirent->d_name, 0); rpath = rootpath(fid->path);
path = estrpath(rpath, fid->dirent->d_name, 0);
memset(&st, 0, sizeof st); memset(&st, 0, sizeof st);
if(stat(path, &st) < 0){ if(stat(path, &st) < 0){
fprint(2, "dirread: stat(%s) failed: %s\n", path, strerror(errno)); fprint(2, "dirread: stat(%s) failed: %s\n", path, strerror(errno));
@ -828,7 +842,7 @@ rwrite(Fcall *rx, Fcall *tx)
void void
rclunk(Fcall *rx, Fcall *tx) rclunk(Fcall *rx, Fcall *tx)
{ {
char *e; char *e, *rpath;
Fid *fid; Fid *fid;
if((fid = oldfidex(rx->fid, -1, &e)) == nil){ if((fid = oldfidex(rx->fid, -1, &e)) == nil){
@ -844,8 +858,10 @@ rclunk(Fcall *rx, Fcall *tx)
} }
} }
} }
else if(fid->omode != -1 && fid->omode&ORCLOSE) else if(fid->omode != -1 && fid->omode&ORCLOSE){
remove(fid->path); rpath = rootpath(fid->path);
remove(rpath);
}
freefid(fid); freefid(fid);
} }
@ -889,7 +905,7 @@ rstat(Fcall *rx, Fcall *tx)
void void
rwstat(Fcall *rx, Fcall *tx) rwstat(Fcall *rx, Fcall *tx)
{ {
char *e; char *e, *opath, *npath;
char *p, *old, *new, *dir; char *p, *old, *new, *dir;
gid_t gid; gid_t gid;
Dir d; Dir d;
@ -959,9 +975,10 @@ rwstat(Fcall *rx, Fcall *tx)
* leave truncate until last. * leave truncate until last.
* (see above comment about atomicity). * (see above comment about atomicity).
*/ */
if((u32int)d.mode != (u32int)~0 && chmod(fid->path, unixmode(&d)) < 0){ opath = estrdup(rootpath(fid->path));
if((u32int)d.mode != (u32int)~0 && chmod(opath, unixmode(&d)) < 0){
if(chatty9p) if(chatty9p)
fprint(2, "chmod(%s, 0%luo) failed\n", fid->path, unixmode(&d)); fprint(2, "chmod(%s, 0%luo) failed\n", opath, unixmode(&d));
seterror(tx, strerror(errno)); seterror(tx, strerror(errno));
return; return;
} }
@ -971,18 +988,18 @@ rwstat(Fcall *rx, Fcall *tx)
t.actime = 0; t.actime = 0;
t.modtime = d.mtime; t.modtime = d.mtime;
if(utime(fid->path, &t) < 0){ if(utime(opath, &t) < 0){
if(chatty9p) if(chatty9p)
fprint(2, "utime(%s) failed\n", fid->path); fprint(2, "utime(%s) failed\n", opath);
seterror(tx, strerror(errno)); seterror(tx, strerror(errno));
return; return;
} }
} }
if(gid != (gid_t)-1 && gid != fid->st.st_gid){ if(gid != (gid_t)-1 && gid != fid->st.st_gid){
if(chown(fid->path, (uid_t)-1, gid) < 0){ if(chown(opath, (uid_t)-1, gid) < 0){
if(chatty9p) if(chatty9p)
fprint(2, "chgrp(%s, %d) failed\n", fid->path, gid); fprint(2, "chgrp(%s, %d) failed\n", opath, gid);
seterror(tx, strerror(errno)); seterror(tx, strerror(errno));
return; return;
} }
@ -998,21 +1015,24 @@ rwstat(Fcall *rx, Fcall *tx)
return; return;
} }
new = estrpath(dir, d.name, 1); new = estrpath(dir, d.name, 1);
if(strcmp(old, new) != 0 && rename(old, new) < 0){ npath = rootpath(new);
if(strcmp(old, new) != 0 && rename(opath, npath) < 0){
if(chatty9p) if(chatty9p)
fprint(2, "rename(%s, %s) failed\n", old, new); fprint(2, "rename(%s, %s) failed\n", old, new);
seterror(tx, strerror(errno)); seterror(tx, strerror(errno));
free(new); free(new);
free(dir); free(dir);
free(opath);
return; return;
} }
fid->path = new; fid->path = new;
free(old); free(old);
free(dir); free(dir);
free(opath);
} }
if((u64int)d.length != (u64int)~0 && truncate(fid->path, d.length) < 0){ if((u64int)d.length != (u64int)~0 && truncate(opath, d.length) < 0){
fprint(2, "truncate(%s, %lld) failed\n", fid->path, d.length); fprint(2, "truncate(%s, %lld) failed\n", opath, d.length);
seterror(tx, strerror(errno)); seterror(tx, strerror(errno));
return; return;
} }
@ -1329,8 +1349,11 @@ freefid(Fid *f)
int int
fidstat(Fid *fid, char **ep) fidstat(Fid *fid, char **ep)
{ {
if(stat(fid->path, &fid->st) < 0){ char *rpath;
fprint(2, "fidstat(%s) failed\n", fid->path);
rpath = rootpath(fid->path);
if(stat(rpath, &fid->st) < 0){
fprint(2, "fidstat(%s) failed\n", rpath);
if(ep) if(ep)
*ep = strerror(errno); *ep = strerror(errno);
return -1; return -1;
@ -1419,7 +1442,7 @@ groupchange(User *u, User *g, char **ep)
int int
userperm(User *u, char *path, int type, int need) userperm(User *u, char *path, int type, int need)
{ {
char *p, *q; char *p, *q, *rpath;
int i, have; int i, have;
struct stat st; struct stat st;
User *g; User *g;
@ -1429,13 +1452,15 @@ userperm(User *u, char *path, int type, int need)
fprint(2, "bad type %d in userperm\n", type); fprint(2, "bad type %d in userperm\n", type);
return -1; return -1;
case Tdot: case Tdot:
if(stat(path, &st) < 0){ rpath = rootpath(path);
fprint(2, "userperm: stat(%s) failed\n", path); if(stat(rpath, &st) < 0){
fprint(2, "userperm: stat(%s) failed\n", rpath);
return -1; return -1;
} }
break; break;
case Tdotdot: case Tdotdot:
p = estrdup(path); rpath = rootpath(path);
p = estrdup(rpath);
if((q = strrchr(p, '/'))==nil){ if((q = strrchr(p, '/'))==nil){
fprint(2, "userperm(%s, ..): bad path\n", p); fprint(2, "userperm(%s, ..): bad path\n", p);
free(p); free(p);
@ -1447,7 +1472,7 @@ userperm(User *u, char *path, int type, int need)
*(q+1) = '\0'; *(q+1) = '\0';
if(stat(p, &st) < 0){ if(stat(p, &st) < 0){
fprint(2, "userperm: stat(%s) (dotdot of %s) failed\n", fprint(2, "userperm: stat(%s) (dotdot of %s) failed\n",
p, path); p, rpath);
free(p); free(p);
return -1; return -1;
} }
@ -1484,11 +1509,12 @@ userperm(User *u, char *path, int type, int need)
int int
userwalk(User *u, char **path, char *elem, Qid *qid, char **ep) userwalk(User *u, char **path, char *elem, Qid *qid, char **ep)
{ {
char *npath; char *npath, *rpath;
struct stat st; struct stat st;
npath = estrpath(*path, elem, 1); npath = estrpath(*path, elem, 1);
if(stat(npath, &st) < 0){ rpath = rootpath(npath);
if(stat(rpath, &st) < 0){
free(npath); free(npath);
*ep = strerror(errno); *ep = strerror(errno);
return -1; return -1;
@ -1503,6 +1529,7 @@ int
useropen(Fid *fid, int omode, char **ep) useropen(Fid *fid, int omode, char **ep)
{ {
int a, o; int a, o;
char *rpath;
/* /*
* Check this anyway, to try to head off problems later. * Check this anyway, to try to head off problems later.
@ -1544,7 +1571,8 @@ useropen(Fid *fid, int omode, char **ep)
*ep = Eperm; *ep = Eperm;
return -1; return -1;
} }
if((fid->dir = opendir(fid->path)) == nil){ rpath = rootpath(fid->path);
if((fid->dir = opendir(rpath)) == nil){
*ep = strerror(errno); *ep = strerror(errno);
return -1; return -1;
} }
@ -1559,7 +1587,8 @@ useropen(Fid *fid, int omode, char **ep)
} }
* *
*/ */
if((fid->fd = open(fid->path, o)) < 0){ rpath = rootpath(fid->path);
if((fid->fd = open(rpath, o)) < 0){
*ep = strerror(errno); *ep = strerror(errno);
return -1; return -1;
} }
@ -1572,10 +1601,12 @@ int
usercreate(Fid *fid, char *elem, int omode, long perm, char **ep) usercreate(Fid *fid, char *elem, int omode, long perm, char **ep)
{ {
int o, m; int o, m;
char *opath, *npath; char *opath, *npath, *rpath;
struct stat st, parent; struct stat st, parent;
User *u;
if(stat(fid->path, &parent) < 0){ rpath = rootpath(fid->path);
if(stat(rpath, &parent) < 0){
*ep = strerror(errno); *ep = strerror(errno);
return -1; return -1;
} }
@ -1592,7 +1623,7 @@ usercreate(Fid *fid, char *elem, int omode, long perm, char **ep)
m = (perm & DMDIR) ? 0777 : 0666; m = (perm & DMDIR) ? 0777 : 0666;
perm = perm & (~m | (fid->st.st_mode & m)); perm = perm & (~m | (fid->st.st_mode & m));
npath = estrpath(fid->path, elem, 1); npath = estrpath(rpath, elem, 1);
if(perm & DMDIR){ if(perm & DMDIR){
if((omode&~ORCLOSE) != OREAD){ if((omode&~ORCLOSE) != OREAD){
*ep = Eperm; *ep = Eperm;
@ -1644,8 +1675,28 @@ usercreate(Fid *fid, char *elem, int omode, long perm, char **ep)
} }
} }
/*
* Change ownership if a default user is specified.
*/
if(defaultuser)
if((u = uname2user(defaultuser)) == nil
|| chown(npath, u->id, -1) < 0){
fprint(2, "chown after create on %s failed\n", npath);
remove(npath); /* race */
free(npath);
fid->path = opath;
if(fid->fd >= 0){
close(fid->fd);
fid->fd = -1;
}else{
closedir(fid->dir);
fid->dir = nil;
}
return -1;
}
opath = fid->path; opath = fid->path;
fid->path = npath; fid->path = estrpath(opath, elem, 1);
if(fidstat(fid, ep) < 0){ if(fidstat(fid, ep) < 0){
fprint(2, "stat after create on %s failed\n", npath); fprint(2, "stat after create on %s failed\n", npath);
remove(npath); /* race */ remove(npath); /* race */
@ -1668,7 +1719,10 @@ usercreate(Fid *fid, char *elem, int omode, long perm, char **ep)
int int
userremove(Fid *fid, char **ep) userremove(Fid *fid, char **ep)
{ {
if(remove(fid->path) < 0){ char *rpath;
rpath = rootpath(fid->path);
if(remove(rpath) < 0){
*ep = strerror(errno); *ep = strerror(errno);
return -1; return -1;
} }
@ -1755,8 +1809,7 @@ main(int argc, char **argv)
umask(0); umask(0);
if(argc == 1) if(argc == 1)
if(chroot(argv[0]) < 0) root = argv[0];
sysfatal("chroot '%s' failed", argv[0]);
none = uname2user("none"); none = uname2user("none");