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package/sudo: fix CVE-2022-43995

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Sudo 1.8.0 through 1.9.12, with the crypt() password backend, contains a
plugins/sudoers/auth/passwd.c array-out-of-bounds error that can result
in a heap-based buffer over-read. This can be triggered by arbitrary
local users with access to Sudo by entering a password of seven
characters or fewer. The impact could vary depending on the compiler and
processor architecture.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
This commit is contained in:
Fabrice Fontaine 2022-11-04 17:26:38 +01:00 committed by Yann E. MORIN
parent 4721367deb
commit 2663449036
2 changed files with 56 additions and 0 deletions
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53
package/sudo/0001-Fix-CVE-2022-43995.patch Normal file
View File

@ -0,0 +1,53 @@
From bd209b9f16fcd1270c13db27ae3329c677d48050 Mon Sep 17 00:00:00 2001
From: "Todd C. Miller" <Todd.Miller@sudo.ws>
Date: Fri, 28 Oct 2022 07:29:55 -0600
Subject: [PATCH] Fix CVE-2022-43995, potential heap overflow for passwords < 8
characters. Starting with sudo 1.8.0 the plaintext password buffer is
dynamically sized so it is not safe to assume that it is at least 9 bytes in
size. Found by Hugo Lefeuvre (University of Manchester) with ConfFuzz.
[Retrieved from:
https://github.com/sudo-project/sudo/commit/bd209b9f16fcd1270c13db27ae3329c677d48050]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
plugins/sudoers/auth/passwd.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/plugins/sudoers/auth/passwd.c b/plugins/sudoers/auth/passwd.c
index b2046eca2..0416861e9 100644
--- a/plugins/sudoers/auth/passwd.c
+++ b/plugins/sudoers/auth/passwd.c
@@ -63,7 +63,7 @@ sudo_passwd_init(struct passwd *pw, sudo_auth *auth)
int
sudo_passwd_verify(struct passwd *pw, char *pass, sudo_auth *auth, struct sudo_conv_callback *callback)
{
- char sav, *epass;
+ char des_pass[9], *epass;
char *pw_epasswd = auth->data;
size_t pw_len;
int matched = 0;
@@ -75,12 +75,12 @@ sudo_passwd_verify(struct passwd *pw, char *pass, sudo_auth *auth, struct sudo_c
/*
* Truncate to 8 chars if standard DES since not all crypt()'s do this.
- * If this turns out not to be safe we will have to use OS #ifdef's (sigh).
*/
- sav = pass[8];
pw_len = strlen(pw_epasswd);
- if (pw_len == DESLEN || HAS_AGEINFO(pw_epasswd, pw_len))
- pass[8] = '\0';
+ if (pw_len == DESLEN || HAS_AGEINFO(pw_epasswd, pw_len)) {
+ strlcpy(des_pass, pass, sizeof(des_pass));
+ pass = des_pass;
+ }
/*
* Normal UN*X password check.
@@ -88,7 +88,6 @@ sudo_passwd_verify(struct passwd *pw, char *pass, sudo_auth *auth, struct sudo_c
* only compare the first DESLEN characters in that case.
*/
epass = (char *) crypt(pass, pw_epasswd);
- pass[8] = sav;
if (epass != NULL) {
if (HAS_AGEINFO(pw_epasswd, pw_len) && strlen(epass) == DESLEN)
matched = !strncmp(pw_epasswd, epass, DESLEN);

3
package/sudo/sudo.mk
View File

@ -23,6 +23,9 @@ SUDO_CONF_OPTS = \
--without-interfaces \ --without-interfaces \
--with-env-editor --with-env-editor
# 0001-Fix-CVE-2022-43995.patch
SUDO_IGNORE_CVES += CVE-2022-43995
ifeq ($(BR2_PACKAGE_LINUX_PAM),y) ifeq ($(BR2_PACKAGE_LINUX_PAM),y)
define SUDO_INSTALL_PAM_CONF define SUDO_INSTALL_PAM_CONF
$(INSTALL) -D -m 0644 package/sudo/sudo.pam $(TARGET_DIR)/etc/pam.d/sudo $(INSTALL) -D -m 0644 package/sudo/sudo.pam $(TARGET_DIR)/etc/pam.d/sudo