Author: db (ports committer)
Date: Thu Mar 7 19:00:00 2013
New Revision: 247919
URL: http://svnweb.freebsd.org/changeset/base/247919
Log:
Cleanup gr_add() so it does not leak mem
This is part of ongoing work on sbin/pw
M libutil.h
M gr_util.c
Approved by: theraven
Modified:
head/lib/libutil/gr_util.c
head/lib/libutil/libutil.h
Modified: head/lib/libutil/gr_util.c
==============================================================================
--- head/lib/libutil/gr_util.c Thu Mar 7 18:55:37 2013 (r247918)
+++ head/lib/libutil/gr_util.c Thu Mar 7 19:00:00 2013 (r247919)
@@ -49,6 +49,8 @@ static char group_dir[PATH_MAX];
static char group_file[PATH_MAX];
static char tempname[PATH_MAX];
static int initialized;
+static size_t grmemlen(const struct group *, const char *, int *);
+static struct group *grcopy(const struct group *gr, struct group *newgr, const
char *, int ndx);
/*
* Initialize statics
@@ -429,90 +431,121 @@ gr_make(const struct group *gr)
struct group *
gr_dup(const struct group *gr)
{
+ return (gr_add(gr, NULL));
+}
+/*
+ * Add a new member name to a struct group.
+ */
+struct group *
+gr_add(const struct group *gr, const char *newmember)
+{
struct group *newgr;
- char *dst;
size_t len;
- int ndx;
int num_mem;
- /* Calculate size of the group. */
- len = sizeof(*newgr);
- if (gr->gr_name != NULL)
- len += strlen(gr->gr_name) + 1;
- if (gr->gr_passwd != NULL)
- len += strlen(gr->gr_passwd) + 1;
- if (gr->gr_mem != NULL) {
- for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++)
- len += strlen(gr->gr_mem[num_mem]) + 1;
- len += (num_mem + 1) * sizeof(*gr->gr_mem);
- } else
- num_mem = -1;
+ num_mem = 0;
+ len = grmemlen(gr, newmember, &num_mem);
/* Create new group and copy old group into it. */
if ((newgr = malloc(len)) == NULL)
return (NULL);
- /* point new gr_mem to end of struct + 1 */
- if (gr->gr_mem != NULL)
+ return (grcopy(gr, newgr, newmember, num_mem));
+}
+
+/* It is safer to walk the pointers given at gr_mem since there is no
+ * guarantee the gr_mem + strings are continguous in the given struct group
+ * but compact the new group into the following form.
+ *
+ * The new struct is laid out like this in memory. The example given is
+ * for a group with two members only.
+ *
+ * {
+ * (char *name)
+ * (char *passwd)
+ * (int gid)
+ * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
+ * gr_mem area
+ * (member1 *)
+ * (member2 *)
+ * (NULL)
+ * (name string)
+ * (passwd string)
+ * (member1 string)
+ * (member2 string)
+ * }
+ */
+/*
+ * Copy the guts of a group plus given name to a preallocated group struct
+ */
+static struct group *
+grcopy(const struct group *gr, struct group *newgr, const char *name, int ndx)
+{
+ char *dst;
+ int i;
+
+ if (name != NULL)
+ ndx++;
+ /* point new gr_mem to end of struct + 1 if there are names */
+ if (ndx != 0)
newgr->gr_mem = (char **)(newgr + 1);
else
newgr->gr_mem = NULL;
/* point dst after the end of all the gr_mem pointers in newgr */
- dst = (char *)&newgr->gr_mem[num_mem + 1];
+ dst = (char *)&newgr->gr_mem[ndx + 1];
if (gr->gr_name != NULL) {
newgr->gr_name = dst;
dst = stpcpy(dst, gr->gr_name) + 1;
- } else {
+ } else
newgr->gr_name = NULL;
- }
if (gr->gr_passwd != NULL) {
newgr->gr_passwd = dst;
dst = stpcpy(dst, gr->gr_passwd) + 1;
- } else {
+ } else
newgr->gr_passwd = NULL;
- }
newgr->gr_gid = gr->gr_gid;
- if (gr->gr_mem != NULL) {
- for (ndx = 0; ndx < num_mem; ndx++) {
- newgr->gr_mem[ndx] = dst;
- dst = stpcpy(dst, gr->gr_mem[ndx]) + 1;
+ if (ndx != 0) {
+ for (i = 0; gr->gr_mem[i] != NULL; i++) {
+ newgr->gr_mem[i] = dst;
+ dst = stpcpy(dst, gr->gr_mem[i]) + 1;
+ }
+ if (name != NULL) {
+ newgr->gr_mem[i++] = dst;
+ dst = stpcpy(dst, name) + 1;
}
- newgr->gr_mem[ndx] = NULL;
+ newgr->gr_mem[i] = NULL;
}
return (newgr);
}
/*
- * Add a new member name to a struct group.
+ * Calculate length of a struct group + given name
*/
-struct group *
-gr_add(struct group *gr, char *newmember)
+static size_t
+grmemlen(const struct group *gr, const char *name, int *num_mem)
{
- size_t mlen;
- int num_mem=0;
- char **members;
- struct group *newgr;
-
- if (newmember == NULL)
- return(gr_dup(gr));
+ size_t len;
+ int i;
+ if (gr == NULL)
+ return (0);
+ /* Calculate size of the group. */
+ len = sizeof(*gr);
+ if (gr->gr_name != NULL)
+ len += strlen(gr->gr_name) + 1;
+ if (gr->gr_passwd != NULL)
+ len += strlen(gr->gr_passwd) + 1;
if (gr->gr_mem != NULL) {
- for (num_mem = 0; gr->gr_mem[num_mem] != NULL; num_mem++) {
- if (strcmp(gr->gr_mem[num_mem], newmember) == 0) {
- errno = EEXIST;
- return (NULL);
- }
+ for (len = i = 0; gr->gr_mem[i] != NULL; i++) {
+ len += strlen(gr->gr_mem[i]) + 1;
+ len += sizeof(*gr->gr_mem);
}
+ *num_mem = i;
}
- /* Allocate enough for current pointers + 1 more and NULL marker */
- mlen = (num_mem + 2) * sizeof(*gr->gr_mem);
- if ((members = malloc(mlen)) == NULL)
- return (NULL);
- memcpy(members, gr->gr_mem, num_mem * sizeof(*gr->gr_mem));
- members[num_mem++] = newmember;
- members[num_mem] = NULL;
- gr->gr_mem = members;
- newgr = gr_dup(gr);
- free(members);
- return (newgr);
+ if (name != NULL) {
+ len += strlen(name) + 1;
+ if (gr->gr_mem == NULL)
+ len += sizeof(*gr->gr_mem);
+ }
+ return(len);
}
/*
Modified: head/lib/libutil/libutil.h
==============================================================================
--- head/lib/libutil/libutil.h Thu Mar 7 18:55:37 2013 (r247918)
+++ head/lib/libutil/libutil.h Thu Mar 7 19:00:00 2013 (r247919)
@@ -167,7 +167,7 @@ int gr_copy(int __ffd, int _tfd, const
struct group *
gr_dup(const struct group *_gr);
struct group *
- gr_add(struct group *_gr, char *_newmember);
+ gr_add(const struct group *_gr, const char *_newmember);
int gr_equal(const struct group *_gr1, const struct group *_gr2);
void gr_fini(void);
int gr_init(const char *_dir, const char *_master);
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