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From e1554d7996a59bf69544f3d8dd4ae683027948f9 Mon Sep 17 00:00:00 2001
From: Hitendra Prajapati <hprajapati@mvista.com>
Date: Tue, 15 Nov 2022 09:17:18 +0530
Subject: [PATCH] CVE-2022-43995
Upstream-Status: Backport [https://github.com/sudo-project/sudo/commit/bd209b9f16fcd1270c13db27ae3329c677d48050]
CVE: CVE-2022-43995
Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
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.
---
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 03c7a16..76a7824 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);
--
2.25.1
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