diff options
Diffstat (limited to 'main/krb5/CVE-2014-5354.patch')
| -rw-r--r-- | main/krb5/CVE-2014-5354.patch | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/main/krb5/CVE-2014-5354.patch b/main/krb5/CVE-2014-5354.patch new file mode 100644 index 0000000000..01aef2c0ed --- /dev/null +++ b/main/krb5/CVE-2014-5354.patch @@ -0,0 +1,113 @@ +From 04038bf3633c4b909b5ded3072dc88c8c419bf16 Mon Sep 17 00:00:00 2001 +From: Ben Kaduk <kaduk@mit.edu> +Date: Wed, 19 Nov 2014 12:04:46 -0500 +Subject: [PATCH] Support keyless principals in LDAP [CVE-2014-5354] + +Operations like "kadmin -q 'addprinc -nokey foo'" or +"kadmin -q 'purgekeys -all foo'" result in principal entries with +no keys present, so krb5_encode_krbsecretkey() would just return +NULL, which then got unconditionally dereferenced in +krb5_add_ber_mem_ldap_mod(). + +Apply some fixes to krb5_encode_krbsecretkey() to handle zero-key +principals better, correct the test for an allocation failure, and +slightly restructure the cleanup handler to be shorter and more +appropriate for the usage. Once it no longer short-circuits when +n_key_data is zero, it will produce an array of length two with both +entries NULL, which is treated as an empty list by the LDAP library, +the correct behavior for a keyless principal. + +However, attributes with empty values are only handled by the LDAP +library for Modify operations, not Add operations (which only get +a sequence of Attribute, with no operation field). Therefore, only +add an empty krbprincipalkey to the modlist when we will be performing a +Modify, and not when we will be performing an Add, which is conditional +on the (misspelled) create_standalone_prinicipal boolean. + +CVE-2014-5354: + +In MIT krb5, when kadmind is configured to use LDAP for the KDC +database, an authenticated remote attacker can cause a NULL +dereference by inserting into the database a principal entry which +contains no long-term keys. + +In order for the LDAP KDC backend to translate a principal entry +from the database abstraction layer into the form expected by the +LDAP schema, the principal's keys are encoded into a +NULL-terminated array of length-value entries to be stored in the +LDAP database. However, the subroutine which produced this array +did not correctly handle the case where no keys were present, +returning NULL instead of an empty array, and the array was +unconditionally dereferenced while adding to the list of LDAP +operations to perform. + +Versions of MIT krb5 prior to 1.12 did not expose a way for +principal entries to have no long-term key material, and +therefore are not vulnerable. + + CVSSv2 Vector: AV:N/AC:M/Au:S/C:N/I:N/A:P/E:H/RL:OF/RC:C + +ticket: 8041 (new) +tags: pullup +target_version: 1.13.1 +subject: kadmind with ldap backend crashes when putting keyless entries +--- + src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c | 25 +++++++++++++++------- + 1 file changed, 17 insertions(+), 8 deletions(-) + +diff --git a/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c b/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c +index 3e560d9..10b5982 100644 +--- a/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c ++++ b/src/plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c +@@ -406,14 +406,14 @@ krb5_encode_krbsecretkey(krb5_key_data *key_data_in, int n_key_data, + int num_versions = 1; + int i, j, last; + krb5_error_code err = 0; +- krb5_key_data *key_data; ++ krb5_key_data *key_data = NULL; + +- if (n_key_data <= 0) ++ if (n_key_data < 0) + return NULL; + + /* Make a shallow copy of the key data so we can alter it. */ + key_data = k5calloc(n_key_data, sizeof(*key_data), &err); +- if (key_data_in == NULL) ++ if (key_data == NULL) + goto cleanup; + memcpy(key_data, key_data_in, n_key_data * sizeof(*key_data)); + +@@ -467,9 +467,8 @@ krb5_encode_krbsecretkey(krb5_key_data *key_data_in, int n_key_data, + free(key_data); + if (err != 0) { + if (ret != NULL) { +- for (i = 0; i <= num_versions; i++) +- if (ret[i] != NULL) +- free (ret[i]); ++ for (i = 0; ret[i] != NULL; i++) ++ free (ret[i]); + free (ret); + ret = NULL; + } +@@ -1036,9 +1035,19 @@ krb5_ldap_put_principal(krb5_context context, krb5_db_entry *entry, + bersecretkey = krb5_encode_krbsecretkey (entry->key_data, + entry->n_key_data, mkvno); + +- if ((st=krb5_add_ber_mem_ldap_mod(&mods, "krbprincipalkey", +- LDAP_MOD_REPLACE | LDAP_MOD_BVALUES, bersecretkey)) != 0) ++ if (bersecretkey == NULL) { ++ st = ENOMEM; + goto cleanup; ++ } ++ /* An empty list of bervals is only accepted for modify operations, ++ * not add operations. */ ++ if (bersecretkey[0] != NULL || !create_standalone_prinicipal) { ++ st = krb5_add_ber_mem_ldap_mod(&mods, "krbprincipalkey", ++ LDAP_MOD_REPLACE | LDAP_MOD_BVALUES, ++ bersecretkey); ++ if (st != 0) ++ goto cleanup; ++ } + + if (!(entry->mask & KADM5_PRINCIPAL)) { + memset(strval, 0, sizeof(strval)); |