git: a8499077ab1b - stable/12 - libc/nss: Restore iterator state when doing passwd/group lookups
Mark Johnston
markj at FreeBSD.org
Sat Feb 20 16:35:55 UTC 2021
The branch stable/12 has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=a8499077ab1b23c432c251874cf931e1025d8636
commit a8499077ab1b23c432c251874cf931e1025d8636
Author: Mark Johnston <markj at FreeBSD.org>
AuthorDate: 2021-01-21 19:30:19 +0000
Commit: Mark Johnston <markj at FreeBSD.org>
CommitDate: 2021-02-20 16:35:32 +0000
libc/nss: Restore iterator state when doing passwd/group lookups
The getpwent(3) and getgrent(3) implementations maintain some internal
iterator state. Interleaved calls to functions which do passwd/group
lookups using a key, such as getpwnam(3), would in some cases clobber
this state, causing a subsequent getpwent() or getgrent() call to
restart iteration from the beginning of the database or to terminate
early. This is particularly troublesome in programming environments
where execution of green threads is interleaved within a single OS
thread.
Take care to restore any iterator state following a keyed lookup. The
"files" provider for the passwd database was already handling this
correctly, but "compat" was not, and both providers had this problem
when accessing the group database.
PR: 252094
Submitted by: Viktor Dukhovni <ietf-dane at dukhovni.org>
(cherry picked from commit 5619d49e07d3942e438f3d06269f3c1c466cf5b7)
---
lib/libc/gen/getgrent.c | 34 +++++++++++++++-------------------
lib/libc/gen/getpwent.c | 18 +++++++++++-------
2 files changed, 26 insertions(+), 26 deletions(-)
diff --git a/lib/libc/gen/getgrent.c b/lib/libc/gen/getgrent.c
index b3699cae3c45..6abccea30c6b 100644
--- a/lib/libc/gen/getgrent.c
+++ b/lib/libc/gen/getgrent.c
@@ -882,16 +882,12 @@ files_group(void *retval, void *mdata, va_list ap)
}
fresh = 1;
}
- if (how == nss_lt_all)
- stayopen = 1;
- else {
- if (!fresh)
- rewind(st->fp);
- stayopen = st->stayopen;
- }
- rv = NS_NOTFOUND;
+ stayopen = (how == nss_lt_all || !fresh) ? 1 : st->stayopen;
if (stayopen)
pos = ftello(st->fp);
+ if (how != nss_lt_all && !fresh)
+ rewind(st->fp);
+ rv = NS_NOTFOUND;
while ((line = fgetln(st->fp, &linesize)) != NULL) {
if (line[linesize-1] == '\n')
linesize--;
@@ -913,13 +909,15 @@ files_group(void *retval, void *mdata, va_list ap)
&buffer[linesize + 1], bufsize - linesize - 1, errnop);
if (rv & NS_TERMINATE)
break;
- if (stayopen)
+ if (how == nss_lt_all)
pos = ftello(st->fp);
}
if (st->fp != NULL && !stayopen) {
fclose(st->fp);
st->fp = NULL;
}
+ if (st->fp != NULL && how != nss_lt_all)
+ fseeko(st->fp, pos, SEEK_SET);
if (rv == NS_SUCCESS && retval != NULL)
*(struct group **)retval = grp;
else if (rv == NS_RETURN && *errnop == ERANGE && st->fp != NULL)
@@ -1364,13 +1362,11 @@ compat_group(void *retval, void *mdata, va_list ap)
}
fresh = 1;
}
- if (how == nss_lt_all)
- stayopen = 1;
- else {
- if (!fresh)
- rewind(st->fp);
- stayopen = st->stayopen;
- }
+ stayopen = (how == nss_lt_all || !fresh) ? 1 : st->stayopen;
+ if (stayopen)
+ pos = ftello(st->fp);
+ if (how != nss_lt_all && !fresh)
+ rewind(st->fp);
docompat:
switch (st->compat) {
case COMPAT_MODE_ALL:
@@ -1431,8 +1427,6 @@ docompat:
break;
}
rv = NS_NOTFOUND;
- if (stayopen)
- pos = ftello(st->fp);
while ((line = fgetln(st->fp, &linesize)) != NULL) {
if (line[linesize-1] == '\n')
linesize--;
@@ -1473,7 +1467,7 @@ docompat:
&buffer[linesize + 1], bufsize - linesize - 1, errnop);
if (rv & NS_TERMINATE)
break;
- if (stayopen)
+ if (how == nss_lt_all)
pos = ftello(st->fp);
}
fin:
@@ -1481,6 +1475,8 @@ fin:
fclose(st->fp);
st->fp = NULL;
}
+ if (st->fp != NULL && how != nss_lt_all)
+ fseeko(st->fp, pos, SEEK_SET);
if (rv == NS_SUCCESS && retval != NULL)
*(struct group **)retval = grp;
else if (rv == NS_RETURN && *errnop == ERANGE && st->fp != NULL)
diff --git a/lib/libc/gen/getpwent.c b/lib/libc/gen/getpwent.c
index 09f84f9576ee..a07ee109e2df 100644
--- a/lib/libc/gen/getpwent.c
+++ b/lib/libc/gen/getpwent.c
@@ -1733,6 +1733,7 @@ compat_passwd(void *retval, void *mdata, va_list ap)
{
char keybuf[MAXLOGNAME + 1];
DBT key, entry;
+ pwkeynum keynum;
struct compat_state *st;
enum nss_lookup_type how;
const char *name;
@@ -1783,9 +1784,10 @@ compat_passwd(void *retval, void *mdata, va_list ap)
rv = NS_NOTFOUND;
goto fin;
}
+ keynum = st->keynum;
stayopen = 1;
} else {
- st->keynum = 0;
+ keynum = 0;
stayopen = st->stayopen;
}
docompat:
@@ -1829,13 +1831,13 @@ docompat:
}
key.data = keybuf;
rv = NS_NOTFOUND;
- while (st->keynum >= 0) {
- st->keynum++;
+ while (keynum >= 0) {
+ keynum++;
if (st->version < _PWD_CURRENT_VERSION) {
- memcpy(&keybuf[1], &st->keynum, sizeof(st->keynum));
- key.size = sizeof(st->keynum) + 1;
+ memcpy(&keybuf[1], &keynum, sizeof(keynum));
+ key.size = sizeof(keynum) + 1;
} else {
- store = htonl(st->keynum);
+ store = htonl(keynum);
memcpy(&keybuf[1], &store, sizeof(store));
key.size = sizeof(store) + 1;
}
@@ -1846,7 +1848,7 @@ docompat:
rv = NS_UNAVAIL;
goto fin;
} else if (rv == 1) {
- st->keynum = -1;
+ keynum = -1;
rv = NS_NOTFOUND;
goto fin;
}
@@ -1931,6 +1933,8 @@ docompat:
break;
}
fin:
+ if (how == nss_lt_all)
+ st->keynum = keynum;
if (st->db != NULL && !stayopen) {
(void)st->db->close(st->db);
st->db = NULL;
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