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Use malloc()ed buffers instead of stack buffers in gr_copy() and pw_copy().

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This allows pw(8) to operate on passwd and group files with longer lines
than could be accomodated by a stack buffer.  It doesn't take more than a
few hundred users to exceed 8192 bytes in /etc/group.

MFC after:	3 weeks
Sponsored by:	The University of Oslo
This commit is contained in:
des 2016-11-28 21:00:19 +00:00
parent 3b96c94478
commit d975e1244d
2 changed files with 48 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
lib/libutil/gr_util.c
View File

@ -164,11 +164,12 @@ gr_tmp(int mfd)
int
gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
{
char buf[8192], *end, *line, *p, *q, *r, t;
char *buf, *end, *line, *p, *q, *r, *tmp;
struct group *fgr;
const struct group *sgr;
size_t len;
size_t len, size;
int eof, readlen;
char t;
if (old_gr == NULL && gr == NULL)
return(-1);
@ -186,6 +187,10 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
if (sgr == NULL)
sgr = gr;
/* initialize the buffer */
if ((buf = malloc(size = 1024)) == NULL)
goto err;
eof = 0;
len = 0;
p = q = end = buf;
@ -199,10 +204,16 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
if (q >= end) {
if (eof)
break;
if ((size_t)(q - p) >= sizeof(buf)) {
warnx("group line too long");
errno = EINVAL; /* hack */
goto err;
while ((size_t)(q - p) >= size) {
if ((tmp = realloc(buf, size * 2)) == NULL) {
warnx("group line too long");
goto err;
}
p = tmp + (p - buf);
q = tmp + (q - buf);
end = tmp + (end - buf);
buf = tmp;
size = size * 2;
}
if (p < end) {
q = memmove(buf, p, end -p);
@ -210,7 +221,7 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
} else {
p = q = end = buf;
}
readlen = read(ffd, end, sizeof(buf) - (end -buf));
readlen = read(ffd, end, size - (end - buf));
if (readlen == -1)
goto err;
else
@ -219,7 +230,7 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
break;
end += len;
len = end - buf;
if (len < (ssize_t)sizeof(buf)) {
if (len < size) {
eof = 1;
if (len > 0 && buf[len -1] != '\n')
++len, *end++ = '\n';
@ -281,7 +292,7 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
if (write(tfd, q, end - q) != end - q)
goto err;
q = buf;
readlen = read(ffd, buf, sizeof(buf));
readlen = read(ffd, buf, size);
if (readlen == 0)
break;
else
@ -303,12 +314,12 @@ gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
write(tfd, "\n", 1) != 1)
goto err;
done:
if (line != NULL)
free(line);
free(line);
free(buf);
return (0);
err:
if (line != NULL)
free(line);
free(line);
free(buf);
return (-1);
}

37
lib/libutil/pw_util.c
View File

@ -427,11 +427,12 @@ pw_make_v7(const struct passwd *pw)
int
pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
{
char buf[8192], *end, *line, *p, *q, *r, t;
char *buf, *end, *line, *p, *q, *r, *tmp;
struct passwd *fpw;
const struct passwd *spw;
size_t len;
size_t len, size;
int eof, readlen;
char t;
if (old_pw == NULL && pw == NULL)
return (-1);
@ -449,6 +450,10 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
if (spw == NULL)
spw = pw;
/* initialize the buffer */
if ((buf = malloc(size = 1024)) == NULL)
goto err;
eof = 0;
len = 0;
p = q = end = buf;
@ -462,10 +467,16 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
if (q >= end) {
if (eof)
break;
if ((size_t)(q - p) >= sizeof(buf)) {
warnx("passwd line too long");
errno = EINVAL; /* hack */
goto err;
while ((size_t)(q - p) >= size) {
if ((tmp = realloc(buf, size * 2)) == NULL) {
warnx("passwd line too long");
goto err;
}
p = tmp + (p - buf);
q = tmp + (q - buf);
end = tmp + (end - buf);
buf = tmp;
size = size * 2;
}
if (p < end) {
q = memmove(buf, p, end - p);
@ -473,7 +484,7 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
} else {
p = q = end = buf;
}
readlen = read(ffd, end, sizeof(buf) - (end - buf));
readlen = read(ffd, end, size - (end - buf));
if (readlen == -1)
goto err;
else
@ -482,7 +493,7 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
break;
end += len;
len = end - buf;
if (len < (ssize_t)sizeof(buf)) {
if (len < size) {
eof = 1;
if (len > 0 && buf[len - 1] != '\n')
++len, *end++ = '\n';
@ -545,7 +556,7 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
if (write(tfd, q, end - q) != end - q)
goto err;
q = buf;
readlen = read(ffd, buf, sizeof(buf));
readlen = read(ffd, buf, size);
if (readlen == 0)
break;
else
@ -567,12 +578,12 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
write(tfd, "\n", 1) != 1)
goto err;
done:
if (line != NULL)
free(line);
free(line);
free(buf);
return (0);
err:
if (line != NULL)
free(line);
free(line);
free(buf);
return (-1);
}