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Use dynamic allocated buffers instead static buffers. No member or

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line length limit anymore - now 500 members or 5000 members are
possible. For security group lines longer than 256K will be count as
an error. 256K should be enough for 65536 users.

Support comments (lines that begin with a #) if compiled with
option -DGROUP_IGNORE_COMMENTS.

Fortunately it seems that all system utilities which use getgrent()
functions are dynamically linked executables. So you need only
rebuild libc.so.3.0 if you want this change. Note: if you have
an old X server which depend on libc.so.2.* you should rebuild
libc.so.2.* too.

Not a 2.2 candidate.
This commit is contained in:
wosch 1996-12-25 21:51:24 +00:00
parent 78f7aad114
commit 8925ccaa67
1 changed files with 92 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

112
lib/libc/gen/getgrent.c
View File

@ -55,10 +55,22 @@ static int _getypgroup(struct group *, const char *, char *);
static int _nextypgroup(struct group *);
#endif
#define MAXGRP 200
static char *members[MAXGRP];
#define MAXLINELENGTH 1024
static char line[MAXLINELENGTH];
/* initial size for malloc and increase steps for realloc */
#define MAXGRP 64
#define MAXLINELENGTH 256
static char **members; /* list of group members */
static int maxgrp; /* current length of **mebers */
static char *line; /* temp buffer for group line */
static int maxlinelength; /* current length of *line */
/*
* Lines longer than MAXLINELENGTHLIMIT will be count as an error.
* <= 0 disable check for maximum line length
* 256K is enough for 64,000 uids
*/
#define MAXLINELENGTHLIMIT (256 * 1024)
struct group *
getgrent()
@ -176,6 +188,21 @@ start_gr()
rewind(_gr_fp);
}
#endif
if (maxlinelength == 0) {
if ((line = (char *)malloc(sizeof(char) *
MAXLINELENGTH)) == NULL)
return(0);
maxlinelength += MAXLINELENGTH;
}
if (maxgrp == 0) {
if ((members = (char **)malloc(sizeof(char **) *
MAXGRP)) == NULL)
return(0);
maxgrp += MAXGRP;
}
return 1;
}
@ -217,24 +244,55 @@ grscan(search, gid, name)
{
register char *cp, **m;
char *bp;
#ifdef YP
int _ypfound;
#endif;
#endif
for (;;) {
#ifdef YP
_ypfound = 0;
#endif
if (!fgets(line, sizeof(line), _gr_fp))
if (fgets(line, maxlinelength, _gr_fp) == NULL)
return(0);
bp = line;
/* skip lines that are too big */
if (!index(line, '\n')) {
int ch;
while ((ch = getc(_gr_fp)) != '\n' && ch != EOF)
;
continue;
if (!index(line, '\n')) {
do {
if (feof(_gr_fp))
return(0);
/* don't allocate infinite memory */
if (MAXLINELENGTHLIMIT > 0 &&
maxlinelength >= MAXLINELENGTHLIMIT)
return(0);
if ((line = (char *)realloc(line,
sizeof(char) *
(maxlinelength + MAXLINELENGTH))) == NULL)
return(0);
if (fgets(line + maxlinelength - 1,
MAXLINELENGTH + 1, _gr_fp) == NULL)
return(0);
maxlinelength += MAXLINELENGTH;
} while (!index(line + maxlinelength -
MAXLINELENGTH - 1, '\n'));
}
#ifdef GROUP_IGNORE_COMMENTS
/*
* Ignore comments: ^[ \t]*#
*/
for (cp = line; *cp != '\0'; cp++)
if (*cp != ' ' && *cp != '\t')
break;
if (*cp == '#')
continue;
#endif
bp = line;
if ((_gr_group.gr_name = strsep(&bp, ":\n")) == NULL)
break;
#ifdef YP
@ -320,9 +378,16 @@ grscan(search, gid, name)
bp = cp;
cp = NULL;
#endif
for (m = _gr_group.gr_mem = members;; bp++) {
if (m == &members[MAXGRP - 1])
break;
for (m = members; ; bp++) {
if (m == (members + maxgrp - 1)) {
if ((members = (char **)
realloc(members,
sizeof(char **) *
(maxgrp + MAXGRP))) == NULL)
return(0);
m = members + maxgrp - 1;
maxgrp += MAXGRP;
}
if (*bp == ',') {
if (cp) {
*bp = '\0';
@ -333,11 +398,13 @@ grscan(search, gid, name)
if (cp) {
*bp = '\0';
*m++ = cp;
}
}
break;
} else if (cp == NULL)
cp = bp;
}
_gr_group.gr_mem = members;
*m = NULL;
return(1);
}
@ -370,9 +437,13 @@ _gr_breakout_yp(struct group *gr, char *result)
if ((s = result) == NULL) return 0;
cp = 0;
for (m = _gr_group.gr_mem = members; /**/; s++) {
if (m == &members[MAXGRP - 1]) {
break;
for (m = members; ; s++) {
if (m == members + maxgrp - 1) {
if ((members = (char **)realloc(members,
sizeof(char **) * (maxgrp + MAXGRP))) == NULL)
return(0);
m = members + maxgrp - 1;
maxgrp += MAXGRP;
}
if (*s == ',') {
if (cp) {
@ -390,6 +461,7 @@ _gr_breakout_yp(struct group *gr, char *result)
cp = s;
}
}
_gr_group.gr_mem = members;
*m = NULL;
return 1;