sudo: CVE-2022-43995 heap-based overflow with very small passwords

Upstream-Status: Backport from https://github.com/sudo-project/sudo/commit/bd209b9f16fcd1270c13db27ae3329c677d48050

(From OE-Core rev: d1bdb663e6a69993d3f42547a27296b606965d47)

Signed-off-by: Hitendra Prajapati <hprajapati@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 60 insertions, 0 deletions

diff --git a/meta/recipes-extended/sudo/sudo/CVE-2022-43995.patch b/meta/recipes-extended/sudo/sudo/CVE-2022-43995.patch
new file mode 100644
index 0000000000..1336c7701d
--- /dev/null
+++ b/meta/recipes-extended/sudo/sudo/CVE-2022-43995.patch
@@ -0,0 +1,59 @@
+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
+
diff --git a/meta/recipes-extended/sudo/sudo_1.8.32.bb b/meta/recipes-extended/sudo/sudo_1.8.32.bb
index 8d16ec2538..10785beedf 100644
--- a/meta/recipes-extended/sudo/sudo_1.8.32.bb
+++ b/meta/recipes-extended/sudo/sudo_1.8.32.bb
@@ -4,6 +4,7 @@ SRC_URI = "https://www.sudo.ws/dist/sudo-${PV}.tar.gz \
            ${@bb.utils.contains('DISTRO_FEATURES', 'pam', '${PAM_SRC_URI}', '', d)} \
            file://0001-Include-sys-types.h-for-id_t-definition.patch \
            file://0001-Fix-includes-when-building-with-musl.patch \
+           file://CVE-2022-43995.patch \
            "
 
 PAM_SRC_URI = "file://sudo.pam"