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    Subject[PATCH ghau51/ghau40 v9 11/11] libaudit: add support to get and set capcontid on a task
    Date
    Add support to be able to set a capability to allow a task to set the
    audit container identifier of descendants.

    See: https://github.com/linux-audit/audit-userspace/issues/51
    See: https://github.com/linux-audit/audit-kernel/issues/90
    See: https://github.com/linux-audit/audit-testsuite/issues/64
    See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID

    Add the audit_get_capcontid() and audit_set_capcontid() calls analogous
    to CAP_AUDIT_CONTROL for descendant user namespaces.

    Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
    ---
    auparse/normalize.c | 1 +
    auparse/normalize_record_map.h | 1 +
    docs/Makefile.am | 1 +
    docs/audit_get_capcontid.3 | 25 ++++++++++++++++
    docs/audit_set_capcontid.3 | 24 +++++++++++++++
    lib/libaudit.c | 68 ++++++++++++++++++++++++++++++++++++++++++
    lib/libaudit.h | 4 +++
    lib/msg_typetab.h | 1 +
    lib/netlink.c | 1 +
    src/ausearch-lol.c | 2 ++
    src/ausearch-parse.c | 1 +
    11 files changed, 129 insertions(+)
    create mode 100644 docs/audit_get_capcontid.3
    create mode 100644 docs/audit_set_capcontid.3

    diff --git a/auparse/normalize.c b/auparse/normalize.c
    index 2d7878ce9ba9..8bcfce280d1a 100644
    --- a/auparse/normalize.c
    +++ b/auparse/normalize.c
    @@ -911,6 +911,7 @@ static const char *normalize_determine_evkind(int type)
    case AUDIT_FEATURE_CHANGE ... AUDIT_REPLACE:
    case AUDIT_USER_DEVICE:
    case AUDIT_SOFTWARE_UPDATE:
    + case AUDIT_SET_CAPCONTID:
    kind = NORM_EVTYPE_CONFIG;
    break;
    case AUDIT_SECCOMP:
    diff --git a/auparse/normalize_record_map.h b/auparse/normalize_record_map.h
    index 7332249c7b34..2e8c87447313 100644
    --- a/auparse/normalize_record_map.h
    +++ b/auparse/normalize_record_map.h
    @@ -26,6 +26,7 @@
    _S(AUDIT_USER, "sent-message")
    _S(AUDIT_LOGIN, "changed-login-id-to")
    _S(AUDIT_CONTAINER_OP, "changed-container-id-to")
    +_S(AUDIT_SET_CAPCONTID, "set-capcontid-to")
    _S(AUDIT_USER_AUTH, "authenticated")
    _S(AUDIT_USER_ACCT, "was-authorized")
    _S(AUDIT_USER_MGMT, "modified-user-account")
    diff --git a/docs/Makefile.am b/docs/Makefile.am
    index 209789bb2051..6b981b296d0c 100644
    --- a/docs/Makefile.am
    +++ b/docs/Makefile.am
    @@ -29,6 +29,7 @@ auditd.conf.5 auditd-plugins.5 \
    audit_delete_rule_data.3 audit_detect_machine.3 \
    audit_encode_nv_string.3 audit_getloginuid.3 \
    audit_get_reply.3 audit_get_session.3 audit_get_containerid.3 \
    +audit_get_capcontid.3 audit_set_capcontid.3 \
    audit_log_acct_message.3 audit_log_user_avc_message.3 \
    audit_log_user_command.3 audit_log_user_comm_message.3 \
    audit_log_user_message.3 audit_log_semanage_message.3 \
    diff --git a/docs/audit_get_capcontid.3 b/docs/audit_get_capcontid.3
    new file mode 100644
    index 000000000000..652a4960a020
    --- /dev/null
    +++ b/docs/audit_get_capcontid.3
    @@ -0,0 +1,25 @@
    +.TH "AUDIT_GET_CAPCONTID" "26" "Aug 2019" "Red Hat" "Linux Audit API"
    +.SH NAME
    +audit_get_capcontid \- Get a program's capability container id value
    +.SH SYNOPSIS
    +.B #include <libaudit.h>
    +.sp
    +int audit_get_capcontid(pid_t pid);
    +
    +.SH DESCRIPTION
    +This function returns the pid task's audit capability container identifier attribute.
    +
    +.SH "RETURN VALUE"
    +
    +This function returns the audit capability container identifier value if it is implemented. It will return a \-1 if the audit capability container identifier is unavailable.
    +
    +.SH "ERRORS"
    +
    +This function returns \-2 on failure. Additionally, in the event of a real error, errno would be set. The function can set errno based on failures of open, read, or strtoull.
    +
    +.SH "SEE ALSO"
    +
    +.BR audit_set_capcontid (3).
    +
    +.SH AUTHOR
    +Richard Guy Briggs
    diff --git a/docs/audit_set_capcontid.3 b/docs/audit_set_capcontid.3
    new file mode 100644
    index 000000000000..70ac8c7a4e95
    --- /dev/null
    +++ b/docs/audit_set_capcontid.3
    @@ -0,0 +1,24 @@
    +.TH "AUDIT_SET_CAPCONTID" "26" "Aug 2019" "Red Hat" "Linux Audit API"
    +.SH NAME
    +audit_set_capcontid \- Set a program's capability container id value
    +.SH SYNOPSIS
    +.B #include <libaudit.h>
    +.sp
    +int audit_set_capcontid(pid_t pid, uint32_t capcontid);
    +
    +.SH "DESCRIPTION"
    +
    +This function sets the pid task's attribute capability container id with the value of capcontid. The capcontid value may only be set by programs with the CAP_AUDIT_CONTROL capability in the initial user namespace or with capcontid. This normally means the root account or root in a container.
    +.sp
    +The capcontid value is part of the task structure and is inheritted by child processes within a user namespace. It is used to enable the capability to set container identifier of a child task in a descendent user namespace. Container orchestrator/engines should set this value only on children it wishes to be able to set audit container identifiers.
    +
    +.SH "RETURN VALUE"
    +
    +This function returns 0 on success and non-zero otherwise.
    +
    +.SH "SEE ALSO"
    +
    +.BR audit_get_capcontid (3).
    +
    +.SH AUTHOR
    +Richard Guy Briggs
    diff --git a/lib/libaudit.c b/lib/libaudit.c
    index 1a7fed76b9b0..4a2678ca2171 100644
    --- a/lib/libaudit.c
    +++ b/lib/libaudit.c
    @@ -992,6 +992,74 @@ uint32_t audit_get_session(void)
    }

    /*
    + * This function will retrieve the capability container identifier or -2 if
    + * there is an error.
    + */
    +uint32_t audit_get_capcontid(pid_t pid)
    +{
    + int capcontid;
    + int len, in;
    + char buf[16], fnbuf[48];
    +
    + if ((audit_get_features() & AUDIT_FEATURE_BITMAP_CONTAINERID) == 0)
    + return -2;
    + errno = 0;
    + snprintf(fnbuf, sizeof(fnbuf), "/proc/%d/audit_capcontainerid", pid);
    + in = open(fnbuf, O_NOFOLLOW|O_RDONLY);
    + if (in < 0)
    + return -2;
    + do {
    + len = read(in, buf, sizeof(buf));
    + } while (len < 0 && errno == EINTR);
    + close(in);
    + if (len < 0 || len >= sizeof(buf))
    + return -2;
    + buf[len] = 0;
    + errno = 0;
    + capcontid = strtol(buf, 0, 10);
    + if (errno)
    + return -2;
    + return capcontid;
    +}
    +
    +/*
    + * This function returns 0 on success and 1 on failure
    + */
    +int audit_set_capcontid(pid_t pid, uint32_t capcontid)
    +{
    + char capcontidbuf[16], fnbuf[48];
    + int o, count, rc = 0;
    +
    + if ((audit_get_features() & AUDIT_FEATURE_BITMAP_CONTAINERID) == 0)
    + return -2;
    + errno = 0;
    + count = snprintf(capcontidbuf, sizeof(capcontidbuf), "%u", capcontid);
    + snprintf(fnbuf, sizeof(fnbuf), "/proc/%d/audit_capcontainerid", pid);
    + o = open(fnbuf, O_NOFOLLOW|O_WRONLY|O_TRUNC);
    + if (o >= 0) {
    + int block, offset = 0;
    +
    + while (count > 0) {
    + block = write(o, &capcontidbuf[offset], (unsigned int)count);
    + if (block < 0) {
    + if (errno == EINTR)
    + continue;
    + audit_msg(LOG_ERR, "Error writing capcontid");
    + close(o);
    + return 1;
    + }
    + offset += block;
    + count -= block;
    + }
    + close(o);
    + } else {
    + audit_msg(LOG_ERR, "Error opening %s", fnbuf);
    + rc = 1;
    + }
    + return rc;
    +}
    +
    +/*
    * This function will retrieve the audit container identifier or -2 if
    * there is an error.
    */
    diff --git a/lib/libaudit.h b/lib/libaudit.h
    index f4e820e9b097..2a140f6d0e4b 100644
    --- a/lib/libaudit.h
    +++ b/lib/libaudit.h
    @@ -255,6 +255,10 @@ extern "C" {
    #define AUDIT_SIGNAL_INFO2 1021 /* auditd signal sender info */
    #endif

    +#ifndef AUDIT_SET_CAPCONTID
    +#define AUDIT_SET_CAPCONTID 1022 /* set capcontid of specified pid */
    +#endif
    +
    #ifndef AUDIT_MMAP
    #define AUDIT_MMAP 1323 /* Descriptor and flags in mmap */
    #endif
    diff --git a/lib/msg_typetab.h b/lib/msg_typetab.h
    index e904ece158ce..453013bf434f 100644
    --- a/lib/msg_typetab.h
    +++ b/lib/msg_typetab.h
    @@ -46,6 +46,7 @@ _S(AUDIT_LOGIN, "LOGIN" )
    //_S(AUDIT_GET_FEATURE, "GET_FEATURE" )
    //_S(AUDIT_SIGNAL_INFO2, "SIGNAL_INFO2" )
    _S(AUDIT_CONTAINER_OP, "CONTAINER_OP" )
    +_S(AUDIT_SET_CAPCONTID, "SET_CAPCONTID" )
    _S(AUDIT_USER_AUTH, "USER_AUTH" )
    _S(AUDIT_USER_ACCT, "USER_ACCT" )
    _S(AUDIT_USER_MGMT, "USER_MGMT" )
    diff --git a/lib/netlink.c b/lib/netlink.c
    index 66a3a3b7e83c..d7c3c6124a68 100644
    --- a/lib/netlink.c
    +++ b/lib/netlink.c
    @@ -186,6 +186,7 @@ static int adjust_reply(struct audit_reply *rep, int len)
    case AUDIT_USER:
    case AUDIT_LOGIN:
    case AUDIT_CONTAINER_OP:
    + case AUDIT_SET_CAPCONTID:
    case AUDIT_KERNEL:
    case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
    case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2:
    diff --git a/src/ausearch-lol.c b/src/ausearch-lol.c
    index 05fe80fe3ad6..8ad88a14f30c 100644
    --- a/src/ausearch-lol.c
    +++ b/src/ausearch-lol.c
    @@ -250,6 +250,8 @@ static void check_events(lol *lo, time_t sec)
    (cur->l->e.type > AUDIT_LOGIN &&
    cur->l->e.type < AUDIT_CONTAINER_OP ) ||
    (cur->l->e.type > AUDIT_CONTAINER_OP &&
    + cur->l->e.type < AUDIT_SET_CAPCONTID ) ||
    + (cur->l->e.type > AUDIT_SET_CAPCONTID &&
    cur->l->e.type < AUDIT_FIRST_EVENT ) ||
    cur->l->e.type == AUDIT_PROCTITLE ||
    (cur->l->e.type >= AUDIT_MAC_UNLBL_ALLOW &&
    diff --git a/src/ausearch-parse.c b/src/ausearch-parse.c
    index 93482be3606e..9d8a5dd2d092 100644
    --- a/src/ausearch-parse.c
    +++ b/src/ausearch-parse.c
    @@ -192,6 +192,7 @@ int extract_search_items(llist *l)
    case AUDIT_MMAP:
    case AUDIT_PROCTITLE:
    case AUDIT_REPLACE...AUDIT_BPF:
    + case AUDIT_SET_CAPCONTID:
    // Nothing to parse
    break;
    case AUDIT_NETFILTER_CFG:
    --
    1.8.3.1
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