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