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+From 57a1e2b274d0a6376d92ada9926e5c5741e7da20 Mon Sep 17 00:00:00 2001
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+From: "Dmitry V. Levin" <ldv@altlinux.org>
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+Date: Fri, 24 Jan 2014 22:18:32 +0000
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+Subject: pam_userdb: fix password hash comparison
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+
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+Starting with commit Linux-PAM-0-77-28-g0b3e583 that introduced hashed
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+passwords support in pam_userdb, hashes are compared case-insensitively.
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+This bug leads to accepting hashes for completely different passwords in
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+addition to those that should be accepted.
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+
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+Additionally, commit Linux-PAM-1_1_6-13-ge2a8187 that added support for
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+modern password hashes with different lengths and settings, did not
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+update the hash comparison accordingly, which leads to accepting
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+computed hashes longer than stored hashes when the latter is a prefix
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+of the former.
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+
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+* modules/pam_userdb/pam_userdb.c (user_lookup): Reject the computed
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+hash whose length differs from the stored hash length.
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+Compare computed and stored hashes case-sensitively.
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+Fixes CVE-2013-7041.
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+
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+Bug-Debian: http://bugs.debian.org/731368
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+Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
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+
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+diff --git a/modules/pam_userdb/pam_userdb.c b/modules/pam_userdb/pam_userdb.c
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+index de8b5b1..ff040e6 100644
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+--- a/modules/pam_userdb/pam_userdb.c
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++++ b/modules/pam_userdb/pam_userdb.c
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+@@ -222,12 +222,15 @@ user_lookup (pam_handle_t *pamh, const char *database, const char *cryptmode,
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+ } else {
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+ cryptpw = crypt (pass, data.dptr);
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+
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+- if (cryptpw) {
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+- compare = strncasecmp (data.dptr, cryptpw, data.dsize);
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++ if (cryptpw && strlen(cryptpw) == (size_t)data.dsize) {
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++ compare = memcmp(data.dptr, cryptpw, data.dsize);
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+ } else {
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+ compare = -2;
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+ if (ctrl & PAM_DEBUG_ARG) {
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+- pam_syslog(pamh, LOG_INFO, "crypt() returned NULL");
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++ if (cryptpw)
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++ pam_syslog(pamh, LOG_INFO, "lengths of computed and stored hashes differ");
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++ else
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++ pam_syslog(pamh, LOG_INFO, "crypt() returned NULL");
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+ }
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+ };
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+
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+--
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+cgit v0.10.2
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+
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