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Diffstat (limited to 'source4/libcli/security/access_check.c')
| -rw-r--r-- | source4/libcli/security/access_check.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/source4/libcli/security/access_check.c b/source4/libcli/security/access_check.c new file mode 100644 index 0000000000..e2ede05545 --- /dev/null +++ b/source4/libcli/security/access_check.c @@ -0,0 +1,151 @@ +/* + Unix SMB/CIFS implementation. + + security access checking routines + + Copyright (C) Andrew Tridgell 2004 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "includes.h" +#include "libcli/security/security.h" + + +/* + perform a SEC_FLAG_MAXIMUM_ALLOWED access check +*/ +static uint32_t access_check_max_allowed(const struct security_descriptor *sd, + const struct security_token *token) +{ + uint32_t denied = 0, granted = 0; + unsigned i; + + if (security_token_has_sid(token, sd->owner_sid)) { + granted |= SEC_STD_WRITE_DAC | SEC_STD_READ_CONTROL | SEC_STD_DELETE; + } else if (security_token_has_privilege(token, SEC_PRIV_RESTORE)) { + granted |= SEC_STD_DELETE; + } + + for (i = 0;i<sd->dacl->num_aces; i++) { + struct security_ace *ace = &sd->dacl->aces[i]; + + if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY) { + continue; + } + + if (!security_token_has_sid(token, &ace->trustee)) { + continue; + } + + switch (ace->type) { + case SEC_ACE_TYPE_ACCESS_ALLOWED: + granted |= ace->access_mask; + break; + case SEC_ACE_TYPE_ACCESS_DENIED: + case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT: + denied |= ace->access_mask; + break; + default: /* Other ACE types not handled/supported */ + break; + } + } + + return granted & ~denied; +} + +/* + the main entry point for access checking. +*/ +NTSTATUS sec_access_check(const struct security_descriptor *sd, + const struct security_token *token, + uint32_t access_desired, + uint32_t *access_granted) +{ + int i; + uint32_t bits_remaining; + + *access_granted = access_desired; + bits_remaining = access_desired; + + /* handle the maximum allowed flag */ + if (access_desired & SEC_FLAG_MAXIMUM_ALLOWED) { + access_desired |= access_check_max_allowed(sd, token); + access_desired &= ~SEC_FLAG_MAXIMUM_ALLOWED; + *access_granted = access_desired; + bits_remaining = access_desired & ~SEC_STD_DELETE; + } + + if (access_desired & SEC_FLAG_SYSTEM_SECURITY) { + if (security_token_has_privilege(token, SEC_PRIV_SECURITY)) { + bits_remaining &= ~SEC_FLAG_SYSTEM_SECURITY; + } else { + return NT_STATUS_PRIVILEGE_NOT_HELD; + } + } + + /* dacl not present allows access */ + if (!(sd->type & SEC_DESC_DACL_PRESENT)) { + *access_granted = access_desired; + return NT_STATUS_OK; + } + + /* empty dacl denies access */ + if (sd->dacl == NULL || sd->dacl->num_aces == 0) { + return NT_STATUS_ACCESS_DENIED; + } + + /* the owner always gets SEC_STD_WRITE_DAC, SEC_STD_READ_CONTROL and SEC_STD_DELETE */ + if ((bits_remaining & (SEC_STD_WRITE_DAC|SEC_STD_READ_CONTROL|SEC_STD_DELETE)) && + security_token_has_sid(token, sd->owner_sid)) { + bits_remaining &= ~(SEC_STD_WRITE_DAC|SEC_STD_READ_CONTROL|SEC_STD_DELETE); + } + if ((bits_remaining & SEC_STD_DELETE) && + security_token_has_privilege(token, SEC_PRIV_RESTORE)) { + bits_remaining &= ~SEC_STD_DELETE; + } + + /* check each ace in turn. */ + for (i=0; bits_remaining && i < sd->dacl->num_aces; i++) { + struct security_ace *ace = &sd->dacl->aces[i]; + + if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY) { + continue; + } + + if (!security_token_has_sid(token, &ace->trustee)) { + continue; + } + + switch (ace->type) { + case SEC_ACE_TYPE_ACCESS_ALLOWED: + bits_remaining &= ~ace->access_mask; + break; + case SEC_ACE_TYPE_ACCESS_DENIED: + case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT: + if (bits_remaining & ace->access_mask) { + return NT_STATUS_ACCESS_DENIED; + } + break; + default: /* Other ACE types not handled/supported */ + break; + } + } + + if (bits_remaining != 0) { + return NT_STATUS_ACCESS_DENIED; + } + + return NT_STATUS_OK; +} |