pam/pam-1.5.1-pam-keyinit-thread-safe.patch
Iker Pedrosa aba8c1f8a4 pam_keyinit: thread-safe implementation
Resolves: #2061696

Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
2022-05-17 10:41:26 +02:00

151 lines
5.2 KiB
Diff

From a35e092e24ee7632346a0e1b4a203c04d4cd2c62 Mon Sep 17 00:00:00 2001
From: Iker Pedrosa <ipedrosa@redhat.com>
Date: Mon, 24 Jan 2022 15:43:23 +0100
Subject: [PATCH] pam_keyinit: thread-safe implementation
* modules/pam_keyinit/pam_keyinit.c: Bypass setre*id() C library calls
with kernel calls and change global variables definitions to be
thread-safe.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1997969
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
Co-Authored-By: Andreas Schneider <asn@samba.org>
---
modules/pam_keyinit/pam_keyinit.c | 60 ++++++++++++++++++++++---------
1 file changed, 44 insertions(+), 16 deletions(-)
diff --git a/modules/pam_keyinit/pam_keyinit.c b/modules/pam_keyinit/pam_keyinit.c
index 92e4953b..df9804b9 100644
--- a/modules/pam_keyinit/pam_keyinit.c
+++ b/modules/pam_keyinit/pam_keyinit.c
@@ -21,6 +21,7 @@
#include <security/pam_modutil.h>
#include <security/pam_ext.h>
#include <sys/syscall.h>
+#include <stdatomic.h>
#define KEY_SPEC_SESSION_KEYRING -3 /* ID for session keyring */
#define KEY_SPEC_USER_KEYRING -4 /* ID for UID-specific keyring */
@@ -31,12 +32,12 @@
#define KEYCTL_REVOKE 3 /* revoke a key */
#define KEYCTL_LINK 8 /* link a key into a keyring */
-static int my_session_keyring = 0;
-static int session_counter = 0;
-static int do_revoke = 0;
-static uid_t revoke_as_uid;
-static gid_t revoke_as_gid;
-static int xdebug = 0;
+static _Thread_local int my_session_keyring = 0;
+static _Atomic int session_counter = 0;
+static _Thread_local int do_revoke = 0;
+static _Thread_local uid_t revoke_as_uid;
+static _Thread_local gid_t revoke_as_gid;
+static _Thread_local int xdebug = 0;
static void debug(pam_handle_t *pamh, const char *fmt, ...)
__attribute__((format(printf, 2, 3)));
@@ -64,6 +65,33 @@ static void error(pam_handle_t *pamh, const char *fmt, ...)
va_end(va);
}
+static int pam_setreuid(uid_t ruid, uid_t euid)
+{
+#if defined(SYS_setreuid32)
+ return syscall(SYS_setreuid32, ruid, euid);
+#else
+ return syscall(SYS_setreuid, ruid, euid);
+#endif
+}
+
+static int pam_setregid(gid_t rgid, gid_t egid)
+{
+#if defined(SYS_setregid32)
+ return syscall(SYS_setregid32, rgid, egid);
+#else
+ return syscall(SYS_setregid, rgid, egid);
+#endif
+}
+
+static int pam_setresuid(uid_t ruid, uid_t euid, uid_t suid)
+{
+#if defined(SYS_setresuid32)
+ return syscall(SYS_setresuid32, ruid, euid, suid);
+#else
+ return syscall(SYS_setresuid, ruid, euid, suid);
+#endif
+}
+
/*
* initialise the session keyring for this process
*/
@@ -140,14 +168,14 @@ static int kill_keyrings(pam_handle_t *pamh, int error_ret)
/* switch to the real UID and GID so that we have permission to
* revoke the key */
- if (revoke_as_gid != old_gid && setregid(-1, revoke_as_gid) < 0) {
+ if (revoke_as_gid != old_gid && pam_setregid(-1, revoke_as_gid) < 0) {
error(pamh, "Unable to change GID to %d temporarily\n", revoke_as_gid);
return error_ret;
}
- if (revoke_as_uid != old_uid && setresuid(-1, revoke_as_uid, old_uid) < 0) {
+ if (revoke_as_uid != old_uid && pam_setresuid(-1, revoke_as_uid, old_uid) < 0) {
error(pamh, "Unable to change UID to %d temporarily\n", revoke_as_uid);
- if (getegid() != old_gid && setregid(-1, old_gid) < 0)
+ if (getegid() != old_gid && pam_setregid(-1, old_gid) < 0)
error(pamh, "Unable to change GID back to %d\n", old_gid);
return error_ret;
}
@@ -157,12 +185,12 @@ static int kill_keyrings(pam_handle_t *pamh, int error_ret)
}
/* return to the original UID and GID (probably root) */
- if (revoke_as_uid != old_uid && setreuid(-1, old_uid) < 0) {
+ if (revoke_as_uid != old_uid && pam_setreuid(-1, old_uid) < 0) {
error(pamh, "Unable to change UID back to %d\n", old_uid);
ret = error_ret;
}
- if (revoke_as_gid != old_gid && setregid(-1, old_gid) < 0) {
+ if (revoke_as_gid != old_gid && pam_setregid(-1, old_gid) < 0) {
error(pamh, "Unable to change GID back to %d\n", old_gid);
ret = error_ret;
}
@@ -215,14 +243,14 @@ static int do_keyinit(pam_handle_t *pamh, int argc, const char **argv, int error
/* switch to the real UID and GID so that the keyring ends up owned by
* the right user */
- if (gid != old_gid && setregid(gid, -1) < 0) {
+ if (gid != old_gid && pam_setregid(gid, -1) < 0) {
error(pamh, "Unable to change GID to %d temporarily\n", gid);
return error_ret;
}
- if (uid != old_uid && setreuid(uid, -1) < 0) {
+ if (uid != old_uid && pam_setreuid(uid, -1) < 0) {
error(pamh, "Unable to change UID to %d temporarily\n", uid);
- if (setregid(old_gid, -1) < 0)
+ if (pam_setregid(old_gid, -1) < 0)
error(pamh, "Unable to change GID back to %d\n", old_gid);
return error_ret;
}
@@ -230,12 +258,12 @@ static int do_keyinit(pam_handle_t *pamh, int argc, const char **argv, int error
ret = init_keyrings(pamh, force, error_ret);
/* return to the original UID and GID (probably root) */
- if (uid != old_uid && setreuid(old_uid, -1) < 0) {
+ if (uid != old_uid && pam_setreuid(old_uid, -1) < 0) {
error(pamh, "Unable to change UID back to %d\n", old_uid);
ret = error_ret;
}
- if (gid != old_gid && setregid(old_gid, -1) < 0) {
+ if (gid != old_gid && pam_setregid(old_gid, -1) < 0) {
error(pamh, "Unable to change GID back to %d\n", old_gid);
ret = error_ret;
}
--
2.35.1