getgrgid() and getpwent() not thread-safe causes segfault in worker MPM
Gea-Suan Lin <[email protected]>
| Newsgroups | gmane.comp.web.fastcgi.devel |
|---|---|
| Message-ID | <[email protected]> |
Hello all, We run apache 2.2 with worker mpm (threading model), and use mod_fastcgi to run PHP 5.2.10 on FreeBSD 7.2-RELEASE-p2. We found httpd will segfault sometimes (2~3 times in one hour) and tried to gdb it, then I found bug is that getgrgid() and getpwent() are not thread-safe. I use getgrgid_r() and getpwent_r() to rewrite (as attachment) and in this 12 hours it looks good. -- * Gea-Suan Lin (public key: Using https://keyserver.pgp.com/ to search) * If you cannot convince them, confuse them. -- Harry S Truman _______________________________________________ FastCGI-developers mailing list FastCGI-developers-xGejAJT2w6xVgU18Zptdi0EOCMrvLtNR@public.gmane.org http://mailman.pins.net/mailman/listinfo.cgi/fastcgi-developers
patch-fcgi_util.c
(text/x-csrc, 1.8 KB)
--- fcgi_util.c.orig 2009-07-08 17:16:29.816884000 +0800
+++ fcgi_util.c 2009-07-09 08:43:09.222180000 +0800
@@ -268,13 +268,17 @@
/* Get the user membership for the file's group. If the
* uid is a member, check the group bits. */
{
- const struct group * const gr = getgrgid(statBuf->st_gid);
- const struct passwd * const pw = getpwuid(uid);
+ char buf[1024], buf2[1024];
+ struct group gr, *r;
+ struct passwd pw, *r2;
- if (gr != NULL && pw != NULL) {
- char **user = gr->gr_mem;
+ getgrgid_r(statBuf->st_gid, &gr, buf, sizeof(buf), &r);
+ getpwuid_r(uid, &pw, buf2, sizeof(buf2), &r2);
+
+ if (r != NULL && r2 != NULL) {
+ char **user = r->gr_mem;
for ( ; *user != NULL; user++) {
- if (strcmp(*user, pw->pw_name) == 0) {
+ if (strcmp(*user, r2->pw_name) == 0) {
if (mode & R_OK && !(statBuf->st_mode & S_IRGRP))
return "read not allowed by group";
if (mode & W_OK && !(statBuf->st_mode & S_IWGRP))
@@ -445,8 +449,9 @@
{
#ifndef WIN32
+ char buf[1024];
struct passwd *pw;
- struct group *gr;
+ struct group gr, *r;
if (fcgi_wrapper == NULL)
return NULL;
@@ -467,14 +472,14 @@
s->username = s->user;
s->gid = gid;
- gr = getgrgid(gid);
- if (gr == NULL) {
+ getgrgid_r(gid, &gr, buf, sizeof(buf), &r);
+ if (r == NULL) {
return ap_psprintf(p,
"getgrgid() couldn't determine the group name for gid '%ld', "
"you probably need to modify the Group directive: %s",
(long)gid, strerror(errno));
}
- s->group = ap_pstrdup(p, gr->gr_name);
+ s->group = ap_pstrdup(p, r->gr_name);
#endif /* !WIN32 */