On 10/19/24 1:23 AM, Ian Kent wrote:
gssd uses getpwuid(3) and getpwnam(3) in a pthreads context but
these functions are not thread safe.
Signed-off-by: Ian Kent <raven@xxxxxxxxxx>
Committed... Thanks for the quick turn around.
steved.
---
utils/gssd/gssd_proc.c | 34 ++++++++++++++++++++++++----------
1 file changed, 24 insertions(+), 10 deletions(-)
diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
index 2ad84c59..01331485 100644
--- a/utils/gssd/gssd_proc.c
+++ b/utils/gssd/gssd_proc.c
@@ -489,7 +489,10 @@ success:
static int
change_identity(uid_t uid)
{
- struct passwd *pw;
+ struct passwd pw;
+ struct passwd *ppw;
+ char *pw_tmp;
+ long tmplen;
int res;
/* drop list of supplimentary groups first */
@@ -502,15 +505,25 @@ change_identity(uid_t uid)
return errno;
}
+ tmplen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (tmplen < 0)
+ tmplen = 16384;
+
+ pw_tmp = malloc(tmplen);
+ if (!pw_tmp) {
+ printerr(0, "WARNING: unable to allocate passwd buffer\n");
+ return errno ? errno : ENOMEM;
+ }
+
/* try to get pwent for user */
- pw = getpwuid(uid);
- if (!pw) {
+ res = getpwuid_r(uid, &pw, pw_tmp, tmplen, &ppw);
+ if (!ppw) {
/* if that doesn't work, try to get one for "nobody" */
- errno = 0;
- pw = getpwnam("nobody");
- if (!pw) {
+ res = getpwnam_r("nobody", &pw, pw_tmp, tmplen, &ppw);
+ if (!ppw) {
printerr(0, "WARNING: unable to determine gid for uid %u\n", uid);
- return errno ? errno : ENOENT;
+ free(pw_tmp);
+ return res ? res : ENOENT;
}
}
@@ -521,12 +534,13 @@ change_identity(uid_t uid)
* other threads. To bypass this, we have to call syscall() directly.
*/
#ifdef __NR_setresgid32
- res = syscall(SYS_setresgid32, pw->pw_gid, pw->pw_gid, pw->pw_gid);
+ res = syscall(SYS_setresgid32, pw.pw_gid, pw.pw_gid, pw.pw_gid);
#else
- res = syscall(SYS_setresgid, pw->pw_gid, pw->pw_gid, pw->pw_gid);
+ res = syscall(SYS_setresgid, pw.pw_gid, pw.pw_gid, pw.pw_gid);
#endif
+ free(pw_tmp);
if (res != 0) {
- printerr(0, "WARNING: failed to set gid to %u!\n", pw->pw_gid);
+ printerr(0, "WARNING: failed to set gid to %u!\n", pw.pw_gid);
return errno;
}
