svn commit: r360401 - in stable/12: stand/defaults sys/kern sys/sys
Kyle Evans
kevans at FreeBSD.org
Mon Apr 27 22:29:25 UTC 2020
Author: kevans
Date: Mon Apr 27 22:29:24 2020
New Revision: 360401
URL: https://svnweb.freebsd.org/changeset/base/360401
Log:
MFC r359953, r359980, r359999: hostuuid preload
r359953:
kern uuid: break format validation out into a separate KPI
This new KPI, validate_uuid, strictly validates the formatting of the input
UUID and, optionally, populates a given struct uuid.
As noted in the header, the key differences are that the new KPI won't
recognize an empty string as a nil UUID and it won't do any kind of semantic
validation on it. Also key is that populating a struct uuid is optional, so
the caller doesn't necessarily need to allocate a bogus one on the stack
just to validate the string.
This KPI has specifically been broken out in support of D24288, which will
preload /etc/hostid in loader so that early boot hostuuid users (e.g.
anything that calls ether_gen_addr) can have a valid hostuuid to work with
once it's been stashed in /etc/hostid.
r359980:
validate_uuid: absorb the rest of parse_uuid with a flags arg
This makes the naming annoyance (validate_uuid vs. parse_uuid) less of an
issue and centralizes all of the functionality into the new KPI while still
making the extra validation optional. The end-result is all the same as far
as hostuuid validation-only goes.
r359999:
Preload hostuuid for early-boot use
prison0's hostuuid will get set by the hostid rc script, either after
generating it and saving it to /etc/hostid or by simply reading /etc/hostid.
Some things (e.g. arbitrary MAC address generation) may use the hostuuid as
a factor in early boot, so providing a way to read /etc/hostid (if it's
available) and using it before userland starts up is desirable. The code is
written such that the preload doesn't *have* to be /etc/hostid, thus not
assuming that there will be newline at the end of the buffer or even the
exact shape of the newline. White trailing whitespace/non-printables
trimmed, the result will be validated as a valid uuid before it's used for
early boot purposes.
The preload can be turned off with hostuuid_load="NO" in /boot/loader.conf,
just as other preloads; it's worth noting that this is a 37-byte file, the
overhead is believed to be generally minimal.
It doesn't seem necessary at this time to be concerned with kern.hostid.
One does wonder if we should consider validating hostuuids coming in
via jail_set(2); some bits seem to care about uuid form and we bother
validating format of smbios-provided uuid and in-fact whatever uuid comes
from /etc/hostid.
Modified:
stable/12/stand/defaults/loader.conf
stable/12/sys/kern/kern_jail.c
stable/12/sys/kern/kern_uuid.c
stable/12/sys/sys/uuid.h
Directory Properties:
stable/12/ (props changed)
Modified: stable/12/stand/defaults/loader.conf
==============================================================================
--- stable/12/stand/defaults/loader.conf Mon Apr 27 22:27:46 2020 (r360400)
+++ stable/12/stand/defaults/loader.conf Mon Apr 27 22:29:24 2020 (r360401)
@@ -33,6 +33,11 @@ bitmap_type="splash_image_data" # and place it on the
screensave_load="NO" # Set to YES to load a screensaver module
screensave_name="green_saver" # Set to the name of the screensaver module
+### Early hostid configuration ############################
+hostuuid_load="YES"
+hostuuid_name="/etc/hostid"
+hostuuid_type="hostuuid"
+
### Random number generator configuration ##################
# See rc.conf(5). The entropy_boot_file config variable must agree with the
# settings below.
Modified: stable/12/sys/kern/kern_jail.c
==============================================================================
--- stable/12/sys/kern/kern_jail.c Mon Apr 27 22:27:46 2020 (r360400)
+++ stable/12/sys/kern/kern_jail.c Mon Apr 27 22:29:24 2020 (r360401)
@@ -48,6 +48,7 @@ __FBSDID("$FreeBSD$");
#include <sys/taskqueue.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
+#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/racct.h>
@@ -61,6 +62,7 @@ __FBSDID("$FreeBSD$");
#include <sys/socket.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
+#include <sys/uuid.h>
#include <sys/vnode.h>
#include <net/if.h>
@@ -75,6 +77,7 @@ __FBSDID("$FreeBSD$");
#include <security/mac/mac_framework.h>
#define DEFAULT_HOSTUUID "00000000-0000-0000-0000-000000000000"
+#define PRISON0_HOSTUUID_MODULE "hostuuid"
MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
static MALLOC_DEFINE(M_PRISON_RACCT, "prison_racct", "Prison racct structures");
@@ -214,10 +217,38 @@ static unsigned jail_max_af_ips = 255;
void
prison0_init(void)
{
+ uint8_t *file, *data;
+ size_t size;
prison0.pr_cpuset = cpuset_ref(thread0.td_cpuset);
prison0.pr_osreldate = osreldate;
strlcpy(prison0.pr_osrelease, osrelease, sizeof(prison0.pr_osrelease));
+
+ /* If we have a preloaded hostuuid, use it. */
+ file = preload_search_by_type(PRISON0_HOSTUUID_MODULE);
+ if (file != NULL) {
+ data = preload_fetch_addr(file);
+ size = preload_fetch_size(file);
+ if (data != NULL) {
+ /*
+ * The preloaded data may include trailing whitespace, almost
+ * certainly a newline; skip over any whitespace or
+ * non-printable characters to be safe.
+ */
+ while (size > 0 && data[size - 1] <= 0x20) {
+ data[size--] = '\0';
+ }
+ if (validate_uuid(data, size, NULL, 0) == 0) {
+ (void)strlcpy(prison0.pr_hostuuid, data,
+ size + 1);
+ } else if (bootverbose) {
+ printf("hostuuid: preload data malformed: '%s'",
+ data);
+ }
+ }
+ }
+ if (bootverbose)
+ printf("hostuuid: using %s\n", prison0.pr_hostuuid);
}
/*
Modified: stable/12/sys/kern/kern_uuid.c
==============================================================================
--- stable/12/sys/kern/kern_uuid.c Mon Apr 27 22:27:46 2020 (r360400)
+++ stable/12/sys/kern/kern_uuid.c Mon Apr 27 22:29:24 2020 (r360401)
@@ -382,19 +382,24 @@ be_uuid_dec(void const *buf, struct uuid *uuid)
}
int
-parse_uuid(const char *str, struct uuid *uuid)
+validate_uuid(const char *str, size_t size, struct uuid *uuid, int flags)
{
u_int c[11];
int n;
- /* An empty string represents a nil UUID. */
- if (*str == '\0') {
- bzero(uuid, sizeof(*uuid));
- return (0);
+ if (size == 0 || *str == '\0') {
+ /* An empty string may represent a nil UUID. */
+ if ((flags & VUUIDF_EMPTYOK) != 0) {
+ if (uuid != NULL)
+ bzero(uuid, sizeof(*uuid));
+ return (0);
+ }
+
+ return (EINVAL);
}
/* The UUID string representation has a fixed length. */
- if (strlen(str) != 36)
+ if (size != 36)
return (EINVAL);
/*
@@ -406,25 +411,39 @@ parse_uuid(const char *str, struct uuid *uuid)
if (str[8] != '-')
return (EINVAL);
+ /* Now check the format. */
n = sscanf(str, "%8x-%4x-%4x-%2x%2x-%2x%2x%2x%2x%2x%2x", c + 0, c + 1,
c + 2, c + 3, c + 4, c + 5, c + 6, c + 7, c + 8, c + 9, c + 10);
/* Make sure we have all conversions. */
if (n != 11)
return (EINVAL);
- /* Successful scan. Build the UUID. */
- uuid->time_low = c[0];
- uuid->time_mid = c[1];
- uuid->time_hi_and_version = c[2];
- uuid->clock_seq_hi_and_reserved = c[3];
- uuid->clock_seq_low = c[4];
- for (n = 0; n < 6; n++)
- uuid->node[n] = c[n + 5];
+ /* Successful scan. Build the UUID if requested. */
+ if (uuid != NULL) {
+ uuid->time_low = c[0];
+ uuid->time_mid = c[1];
+ uuid->time_hi_and_version = c[2];
+ uuid->clock_seq_hi_and_reserved = c[3];
+ uuid->clock_seq_low = c[4];
+ for (n = 0; n < 6; n++)
+ uuid->node[n] = c[n + 5];
+ }
- /* Check semantics... */
+ if ((flags & VUUIDF_CHECKSEMANTICS) == 0)
+ return (0);
+
return (((c[3] & 0x80) != 0x00 && /* variant 0? */
(c[3] & 0xc0) != 0x80 && /* variant 1? */
(c[3] & 0xe0) != 0xc0) ? EINVAL : 0); /* variant 2? */
+}
+
+#define VUUIDF_PARSEFLAGS (VUUIDF_EMPTYOK | VUUIDF_CHECKSEMANTICS)
+
+int
+parse_uuid(const char *str, struct uuid *uuid)
+{
+
+ return (validate_uuid(str, strlen(str), uuid, VUUIDF_PARSEFLAGS));
}
int
Modified: stable/12/sys/sys/uuid.h
==============================================================================
--- stable/12/sys/sys/uuid.h Mon Apr 27 22:27:46 2020 (r360400)
+++ stable/12/sys/sys/uuid.h Mon Apr 27 22:29:24 2020 (r360401)
@@ -66,7 +66,20 @@ int uuid_ether_del(const uint8_t *);
int snprintf_uuid(char *, size_t, struct uuid *);
int printf_uuid(struct uuid *);
int sbuf_printf_uuid(struct sbuf *, struct uuid *);
+
+/*
+ * validate_uuid will, with no flags passed, validate only the format of the
+ * passed in UUID. Flags below are available to give it part of or all of the
+ * functionality that parse_uuid has traditionally had: acknowledging an empty
+ * string as valid, and checking the semantics of the UUID as well.
+ */
+int validate_uuid(const char *, size_t, struct uuid *, int);
int parse_uuid(const char *, struct uuid *);
+
+/* Flags to validate_uuid(). */
+#define VUUIDF_EMPTYOK 0x0001
+#define VUUIDF_CHECKSEMANTICS 0x0002
+
int uuidcmp(const struct uuid *, const struct uuid *);
void be_uuid_dec(void const *buf, struct uuid *uuid);
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