From 70eb747df681779af906fb02fd667ea3a505e6a3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Mon, 8 Apr 2024 17:25:57 +0200 Subject: [PATCH] newrole: use ROWHAMMER resistant values MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use values for success and failure that are more resistent to bit flips, to harden against potential ROWHAMMER attacks. Inspired by [1]. [1]: https://github.com/sudo-project/sudo/commit/7873f8334c8d31031f8cfa83bd97ac6029309e4f Signed-off-by: Christian Göttsche --- policycoreutils/newrole/newrole.c | 35 +++++++++++++++++-------------- 1 file changed, 19 insertions(+), 16 deletions(-) diff --git a/policycoreutils/newrole/newrole.c b/policycoreutils/newrole/newrole.c index 59a5caa35..618c41012 100644 --- a/policycoreutils/newrole/newrole.c +++ b/policycoreutils/newrole/newrole.c @@ -89,6 +89,9 @@ #define PACKAGE "policycoreutils" /* the name of this package lang translation */ #endif +#define ALLOW 0x52a2925 +#define DENY 0xad5d6da + #define TRUE 1 #define FALSE 0 @@ -174,8 +177,8 @@ static const char *service_name = "newrole"; * out: nothing * return: value condition * ----- --------- - * 1 PAM thinks that the user authenticated themselves properly - * 0 otherwise + * ALLOW PAM thinks that the user authenticated themselves properly + * DENY otherwise * * This function uses PAM to authenticate the user running this * program. This is the only function in this program that makes PAM @@ -184,7 +187,7 @@ static const char *service_name = "newrole"; static int authenticate_via_pam(const char *ttyn, pam_handle_t * pam_handle) { - int result = 0; /* set to 0 (not authenticated) by default */ + int result = DENY; /* set to DENY (not authenticated) by default */ int pam_rc; /* pam return code */ const char *tty_name; @@ -210,7 +213,7 @@ static int authenticate_via_pam(const char *ttyn, pam_handle_t * pam_handle) /* Ask PAM to verify acct_mgmt */ pam_rc = pam_acct_mgmt(pam_handle, 0); if (pam_rc == PAM_SUCCESS) { - result = 1; /* user authenticated OK! */ + result = ALLOW; /* user authenticated OK! */ } out: @@ -348,12 +351,12 @@ static int streq_constant(const char *userinput, const char *secret) s_len = strlen(secret); if (u_len != s_len) - return 0; + return DENY; for (i = 0; i < u_len; i++) ret |= x[i] ^ y[i]; - return ret == 0; + return ret == 0 ? ALLOW : DENY; } /* authenticate_via_shadow_passwd() @@ -362,9 +365,9 @@ static int streq_constant(const char *userinput, const char *secret) * out: nothing * return: value condition * ----- --------- - * 1 user authenticated themselves properly according to the + * ALLOW user authenticated themselves properly according to the * shadow passwd file. - * 0 otherwise + * DENY otherwise * * This function uses the shadow passwd file to thenticate the user running * this program. @@ -382,14 +385,14 @@ static int authenticate_via_shadow_passwd(const char *uname) if (!(p_shadow_line)) { fprintf(stderr, _("Cannot find your entry in the shadow " "passwd file.\n")); - return 0; + return DENY; } /* Ask user to input unencrypted password */ if (!(unencrypted_password_s = getpass(PASSWORD_PROMPT))) { fprintf(stderr, _("getpass cannot open /dev/tty\n")); memzero(p_shadow_line->sp_pwdp, strlen(p_shadow_line->sp_pwdp)); - return 0; + return DENY; } /* Use crypt() to encrypt user's input password. */ @@ -400,7 +403,7 @@ static int authenticate_via_shadow_passwd(const char *uname) if (errno || !encrypted_password_s) { fprintf(stderr, _("Cannot encrypt password.\n")); memzero(p_shadow_line->sp_pwdp, strlen(p_shadow_line->sp_pwdp)); - return 0; + return DENY; } ret = streq_constant(encrypted_password_s, p_shadow_line->sp_pwdp); @@ -416,7 +419,7 @@ static int authenticate_via_shadow_passwd(const char *uname) */ static int verify_shell(const char *shell_name) { - int found = 0; + int found = DENY; const char *buf; if (!(shell_name && shell_name[0])) @@ -429,7 +432,7 @@ static int verify_shell(const char *shell_name) /* check the shell skipping newline char */ if (!strcmp(shell_name, buf)) { - found = 1; + found = ALLOW; break; } } @@ -479,7 +482,7 @@ static int extract_pw_data(struct passwd *pw_copy) goto out_free; } - if (verify_shell(pw->pw_shell) == 0) { + if (verify_shell(pw->pw_shell) != ALLOW) { fprintf(stderr, _("Error! Shell is not valid.\n")); goto out_free; } @@ -1182,9 +1185,9 @@ int main(int argc, char *argv[]) goto err_free; } - if (!authenticate_via_pam(ttyn, pam_handle)) + if (authenticate_via_pam(ttyn, pam_handle) != ALLOW) #else - if (!authenticate_via_shadow_passwd(pw.pw_name)) + if (authenticate_via_shadow_passwd(pw.pw_name) != ALLOW) #endif { fprintf(stderr, _("newrole: incorrect password for %s\n"),