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Smack: allow for significantly longer Smack labels v4

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V4 updated to current linux-security#next
Targeted for git://gitorious.org/smack-next/kernel.git

Modern application runtime environments like to use
naming schemes that are structured and generated without
human intervention. Even though the Smack limit of 23
characters for a label name is perfectly rational for
human use there have been complaints that the limit is
a problem in environments where names are composed from
a set or sources, including vendor, author, distribution
channel and application name. Names like

	softwarehouse-pgwodehouse-coolappstore-mellowmuskrats

are becoming harder to avoid. This patch introduces long
label support in Smack. Labels are now limited to 255
characters instead of the old 23.

The primary reason for limiting the labels to 23 characters
was so they could be directly contained in CIPSO category sets.
This is still done were possible, but for labels that are too
large a mapping is required. This is perfectly safe for communication
that stays "on the box" and doesn't require much coordination
between boxes beyond what would have been required to keep label
names consistent.

The bulk of this patch is in smackfs, adding and updating
administrative interfaces. Because existing APIs can't be
changed new ones that do much the same things as old ones
have been introduced.

The Smack specific CIPSO data representation has been removed
and replaced with the data format used by netlabel. The CIPSO
header is now computed when a label is imported rather than
on use. This results in improved IP performance. The smack
label is now allocated separately from the containing structure,
allowing for larger strings.

Four new /smack interfaces have been introduced as four
of the old interfaces strictly required labels be specified
in fixed length arrays.

The access interface is supplemented with the check interface:
	access  "Subject                 Object                  rwxat"
	access2 "Subject Object rwaxt"

The load interface is supplemented with the rules interface:
	load   "Subject                 Object                  rwxat"
	load2  "Subject Object rwaxt"

The load-self interface is supplemented with the self-rules interface:
	load-self   "Subject                 Object                  rwxat"
	load-self2  "Subject Object rwaxt"

The cipso interface is supplemented with the wire interface:
	cipso  "Subject                  lvl cnt  c1  c2 ..."
	cipso2 "Subject lvl cnt  c1  c2 ..."

The old interfaces are maintained for compatibility.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
This commit is contained in:
Casey Schaufler 2012-05-06 15:22:02 -07:00 committed by Casey Schaufler
parent ceffec5541
commit f7112e6c9a
5 changed files with 1120 additions and 581 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

202
Documentation/security/Smack.txt
View file

@ -15,7 +15,7 @@ at hand.
Smack consists of three major components:
- The kernel
- A start-up script and a few modified applications
- Basic utilities, which are helpful but not required
- Configuration data
The kernel component of Smack is implemented as a Linux
@ -23,37 +23,28 @@ Security Modules (LSM) module. It requires netlabel and
works best with file systems that support extended attributes,
although xattr support is not strictly required.
It is safe to run a Smack kernel under a "vanilla" distribution.
Smack kernels use the CIPSO IP option. Some network
configurations are intolerant of IP options and can impede
access to systems that use them as Smack does.
The startup script etc-init.d-smack should be installed
in /etc/init.d/smack and should be invoked early in the
start-up process. On Fedora rc5.d/S02smack is recommended.
This script ensures that certain devices have the correct
Smack attributes and loads the Smack configuration if
any is defined. This script invokes two programs that
ensure configuration data is properly formatted. These
programs are /usr/sbin/smackload and /usr/sin/smackcipso.
The system will run just fine without these programs,
but it will be difficult to set access rules properly.
The current git repositories for Smack user space are:
A version of "ls" that provides a "-M" option to display
Smack labels on long listing is available.
git@gitorious.org:meego-platform-security/smackutil.git
git@gitorious.org:meego-platform-security/libsmack.git
A hacked version of sshd that allows network logins by users
with specific Smack labels is available. This version does
not work for scp. You must set the /etc/ssh/sshd_config
line:
UsePrivilegeSeparation no
These should make and install on most modern distributions.
There are three commands included in smackutil:
The format of /etc/smack/usr is:
username smack
smackload - properly formats data for writing to /smack/load
smackcipso - properly formats data for writing to /smack/cipso
chsmack - display or set Smack extended attribute values
In keeping with the intent of Smack, configuration data is
minimal and not strictly required. The most important
configuration step is mounting the smackfs pseudo filesystem.
If smackutil is installed the startup script will take care
of this, but it can be manually as well.
Add this line to /etc/fstab:
@ -61,19 +52,148 @@ Add this line to /etc/fstab:
and create the /smack directory for mounting.
Smack uses extended attributes (xattrs) to store file labels.
The command to set a Smack label on a file is:
Smack uses extended attributes (xattrs) to store labels on filesystem
objects. The attributes are stored in the extended attribute security
name space. A process must have CAP_MAC_ADMIN to change any of these
attributes.
The extended attributes that Smack uses are:
SMACK64
Used to make access control decisions. In almost all cases
the label given to a new filesystem object will be the label
of the process that created it.
SMACK64EXEC
The Smack label of a process that execs a program file with
this attribute set will run with this attribute's value.
SMACK64MMAP
Don't allow the file to be mmapped by a process whose Smack
label does not allow all of the access permitted to a process
with the label contained in this attribute. This is a very
specific use case for shared libraries.
SMACK64TRANSMUTE
Can only have the value "TRUE". If this attribute is present
on a directory when an object is created in the directory and
the Smack rule (more below) that permitted the write access
to the directory includes the transmute ("t") mode the object
gets the label of the directory instead of the label of the
creating process. If the object being created is a directory
the SMACK64TRANSMUTE attribute is set as well.
SMACK64IPIN
This attribute is only available on file descriptors for sockets.
Use the Smack label in this attribute for access control
decisions on packets being delivered to this socket.
SMACK64IPOUT
This attribute is only available on file descriptors for sockets.
Use the Smack label in this attribute for access control
decisions on packets coming from this socket.
There are multiple ways to set a Smack label on a file:
# attr -S -s SMACK64 -V "value" path
# chsmack -a value path
NOTE: Smack labels are limited to 23 characters. The attr command
does not enforce this restriction and can be used to set
invalid Smack labels on files.
A process can see the smack label it is running with by
reading /proc/self/attr/current. A process with CAP_MAC_ADMIN
can set the process smack by writing there.
If you don't do anything special all users will get the floor ("_")
label when they log in. If you do want to log in via the hacked ssh
at other labels use the attr command to set the smack value on the
home directory and its contents.
Most Smack configuration is accomplished by writing to files
in the smackfs filesystem. This pseudo-filesystem is usually
mounted on /smack.
access
This interface reports whether a subject with the specified
Smack label has a particular access to an object with a
specified Smack label. Write a fixed format access rule to
this file. The next read will indicate whether the access
would be permitted. The text will be either "1" indicating
access, or "0" indicating denial.
access2
This interface reports whether a subject with the specified
Smack label has a particular access to an object with a
specified Smack label. Write a long format access rule to
this file. The next read will indicate whether the access
would be permitted. The text will be either "1" indicating
access, or "0" indicating denial.
ambient
This contains the Smack label applied to unlabeled network
packets.
cipso
This interface allows a specific CIPSO header to be assigned
to a Smack label. The format accepted on write is:
"%24s%4d%4d"["%4d"]...
The first string is a fixed Smack label. The first number is
the level to use. The second number is the number of categories.
The following numbers are the categories.
"level-3-cats-5-19 3 2 5 19"
cipso2
This interface allows a specific CIPSO header to be assigned
to a Smack label. The format accepted on write is:
"%s%4d%4d"["%4d"]...
The first string is a long Smack label. The first number is
the level to use. The second number is the number of categories.
The following numbers are the categories.
"level-3-cats-5-19 3 2 5 19"
direct
This contains the CIPSO level used for Smack direct label
representation in network packets.
doi
This contains the CIPSO domain of interpretation used in
network packets.
load
This interface allows access control rules in addition to
the system defined rules to be specified. The format accepted
on write is:
"%24s%24s%5s"
where the first string is the subject label, the second the
object label, and the third the requested access. The access
string may contain only the characters "rwxat-", and specifies
which sort of access is allowed. The "-" is a placeholder for
permissions that are not allowed. The string "r-x--" would
specify read and execute access. Labels are limited to 23
characters in length.
load2
This interface allows access control rules in addition to
the system defined rules to be specified. The format accepted
on write is:
"%s %s %s"
where the first string is the subject label, the second the
object label, and the third the requested access. The access
string may contain only the characters "rwxat-", and specifies
which sort of access is allowed. The "-" is a placeholder for
permissions that are not allowed. The string "r-x--" would
specify read and execute access.
load-self
This interface allows process specific access rules to be
defined. These rules are only consulted if access would
otherwise be permitted, and are intended to provide additional
restrictions on the process. The format is the same as for
the load interface.
load-self2
This interface allows process specific access rules to be
defined. These rules are only consulted if access would
otherwise be permitted, and are intended to provide additional
restrictions on the process. The format is the same as for
the load2 interface.
logging
This contains the Smack logging state.
mapped
This contains the CIPSO level used for Smack mapped label
representation in network packets.
netlabel
This interface allows specific internet addresses to be
treated as single label hosts. Packets are sent to single
label hosts without CIPSO headers, but only from processes
that have Smack write access to the host label. All packets
received from single label hosts are given the specified
label. The format accepted on write is:
"%d.%d.%d.%d label" or "%d.%d.%d.%d/%d label".
onlycap
This contains the label processes must have for CAP_MAC_ADMIN
and CAP_MAC_OVERRIDE to be effective. If this file is empty
these capabilities are effective at for processes with any
label. The value is set by writing the desired label to the
file or cleared by writing "-" to the file.
You can add access rules in /etc/smack/accesses. They take the form:
@ -83,10 +203,6 @@ access is a combination of the letters rwxa which specify the
kind of access permitted a subject with subjectlabel on an
object with objectlabel. If there is no rule no access is allowed.
A process can see the smack label it is running with by
reading /proc/self/attr/current. A privileged process can
set the process smack by writing there.
Look for additional programs on http://schaufler-ca.com
From the Smack Whitepaper:
@ -186,7 +302,7 @@ team. Smack labels are unstructured, case sensitive, and the only operation
ever performed on them is comparison for equality. Smack labels cannot
contain unprintable characters, the "/" (slash), the "\" (backslash), the "'"
(quote) and '"' (double-quote) characters.
Smack labels cannot begin with a '-', which is reserved for special options.
Smack labels cannot begin with a '-'. This is reserved for special options.
There are some predefined labels:
@ -194,7 +310,7 @@ There are some predefined labels:
^ Pronounced "hat", a single circumflex character.
* Pronounced "star", a single asterisk character.
? Pronounced "huh", a single question mark character.
@ Pronounced "Internet", a single at sign character.
@ Pronounced "web", a single at sign character.
Every task on a Smack system is assigned a label. System tasks, such as
init(8) and systems daemons, are run with the floor ("_") label. User tasks
@ -246,13 +362,14 @@ The format of an access rule is:
Where subject-label is the Smack label of the task, object-label is the Smack
label of the thing being accessed, and access is a string specifying the sort
of access allowed. The Smack labels are limited to 23 characters. The access
specification is searched for letters that describe access modes:
of access allowed. The access specification is searched for letters that
describe access modes:
a: indicates that append access should be granted.
r: indicates that read access should be granted.
w: indicates that write access should be granted.
x: indicates that execute access should be granted.
t: indicates that the rule requests transmutation.
Uppercase values for the specification letters are allowed as well.
Access mode specifications can be in any order. Examples of acceptable rules
@ -273,7 +390,7 @@ Examples of unacceptable rules are:
Spaces are not allowed in labels. Since a subject always has access to files
with the same label specifying a rule for that case is pointless. Only
valid letters (rwxaRWXA) and the dash ('-') character are allowed in
valid letters (rwxatRWXAT) and the dash ('-') character are allowed in
access specifications. The dash is a placeholder, so "a-r" is the same
as "ar". A lone dash is used to specify that no access should be allowed.
@ -297,6 +414,13 @@ but not any of its attributes by the circumstance of having read access to the
containing directory but not to the differently labeled file. This is an
artifact of the file name being data in the directory, not a part of the file.
If a directory is marked as transmuting (SMACK64TRANSMUTE=TRUE) and the
access rule that allows a process to create an object in that directory
includes 't' access the label assigned to the new object will be that
of the directory, not the creating process. This makes it much easier
for two processes with different labels to share data without granting
access to all of their files.
IPC objects, message queues, semaphore sets, and memory segments exist in flat
namespaces and access requests are only required to match the object in
question.

56
security/smack/smack.h
View file

@ -23,13 +23,19 @@
#include <linux/lsm_audit.h>
/*
* Smack labels were limited to 23 characters for a long time.
*/
#define SMK_LABELLEN 24
#define SMK_LONGLABEL 256
/*
* Maximum number of bytes for the levels in a CIPSO IP option.
* Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
* bigger than can be used, and 24 is the next lower multiple
* of 8, and there are too many issues if there isn't space set
* aside for the terminating null byte.
*/
#define SMK_MAXLEN 23
#define SMK_LABELLEN (SMK_MAXLEN+1)
#define SMK_CIPSOLEN 24
struct superblock_smack {
char *smk_root;
@ -78,15 +84,6 @@ struct smack_rule {
int smk_access;
};
/*
* An entry in the table mapping smack values to
* CIPSO level/category-set values.
*/
struct smack_cipso {
int smk_level;
char smk_catset[SMK_LABELLEN];
};
/*
* An entry in the table identifying hosts.
*/
@ -114,22 +111,19 @@ struct smk_netlbladdr {
* interfaces don't. The secid should go away when all of
* these components have been repaired.
*
* If there is a cipso value associated with the label it
* gets stored here, too. This will most likely be rare as
* the cipso direct mapping in used internally.
* The cipso value associated with the label gets stored here, too.
*
* Keep the access rules for this subject label here so that
* the entire set of rules does not need to be examined every
* time.
*/
struct smack_known {
struct list_head list;
char smk_known[SMK_LABELLEN];
u32 smk_secid;
struct smack_cipso *smk_cipso;
spinlock_t smk_cipsolock; /* for changing cipso map */
struct list_head smk_rules; /* access rules */
struct mutex smk_rules_lock; /* lock for the rules */
struct list_head list;
char *smk_known;
u32 smk_secid;
struct netlbl_lsm_secattr smk_netlabel; /* on wire labels */
struct list_head smk_rules; /* access rules */
struct mutex smk_rules_lock; /* lock for rules */
};
/*
@ -166,6 +160,7 @@ struct smack_known {
#define SMACK_CIPSO_DOI_DEFAULT 3 /* Historical */
#define SMACK_CIPSO_DOI_INVALID -1 /* Not a DOI */
#define SMACK_CIPSO_DIRECT_DEFAULT 250 /* Arbitrary */
#define SMACK_CIPSO_MAPPED_DEFAULT 251 /* Also arbitrary */
#define SMACK_CIPSO_MAXCATVAL 63 /* Bigger gets harder */
#define SMACK_CIPSO_MAXLEVEL 255 /* CIPSO 2.2 standard */
#define SMACK_CIPSO_MAXCATNUM 239 /* CIPSO 2.2 standard */
@ -216,10 +211,9 @@ struct inode_smack *new_inode_smack(char *);
int smk_access_entry(char *, char *, struct list_head *);
int smk_access(char *, char *, int, struct smk_audit_info *);
int smk_curacc(char *, u32, struct smk_audit_info *);
int smack_to_cipso(const char *, struct smack_cipso *);
char *smack_from_cipso(u32, char *);
char *smack_from_secid(const u32);
void smk_parse_smack(const char *string, int len, char *smack);
char *smk_parse_smack(const char *string, int len);
int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
char *smk_import(const char *, int);
struct smack_known *smk_import_entry(const char *, int);
struct smack_known *smk_find_entry(const char *);
@ -229,6 +223,7 @@ u32 smack_to_secid(const char *);
* Shared data.
*/
extern int smack_cipso_direct;
extern int smack_cipso_mapped;
extern char *smack_net_ambient;
extern char *smack_onlycap;
extern const char *smack_cipso_option;
@ -240,23 +235,12 @@ extern struct smack_known smack_known_invalid;
extern struct smack_known smack_known_star;
extern struct smack_known smack_known_web;
extern struct mutex smack_known_lock;
extern struct list_head smack_known_list;
extern struct list_head smk_netlbladdr_list;
extern struct security_operations smack_ops;
/*
* Stricly for CIPSO level manipulation.
* Set the category bit number in a smack label sized buffer.
*/
static inline void smack_catset_bit(int cat, char *catsetp)
{
if (cat > SMK_LABELLEN * 8)
return;
catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
}
/*
* Is the directory transmuting?
*/

231
security/smack/smack_access.c
View file

@ -19,37 +19,31 @@
struct smack_known smack_known_huh = {
.smk_known = "?",
.smk_secid = 2,
.smk_cipso = NULL,
};
struct smack_known smack_known_hat = {
.smk_known = "^",
.smk_secid = 3,
.smk_cipso = NULL,
};
struct smack_known smack_known_star = {
.smk_known = "*",
.smk_secid = 4,
.smk_cipso = NULL,
};
struct smack_known smack_known_floor = {
.smk_known = "_",
.smk_secid = 5,
.smk_cipso = NULL,
};
struct smack_known smack_known_invalid = {
.smk_known = "",
.smk_secid = 6,
.smk_cipso = NULL,
};
struct smack_known smack_known_web = {
.smk_known = "@",
.smk_secid = 7,
.smk_cipso = NULL,
};
LIST_HEAD(smack_known_list);
@ -331,7 +325,7 @@ void smack_log(char *subject_label, char *object_label, int request,
}
#endif
static DEFINE_MUTEX(smack_known_lock);
DEFINE_MUTEX(smack_known_lock);
/**
* smk_find_entry - find a label on the list, return the list entry
@ -345,7 +339,7 @@ struct smack_known *smk_find_entry(const char *string)
struct smack_known *skp;
list_for_each_entry_rcu(skp, &smack_known_list, list) {
if (strncmp(skp->smk_known, string, SMK_MAXLEN) == 0)
if (strcmp(skp->smk_known, string) == 0)
return skp;
}
@ -356,27 +350,76 @@ struct smack_known *smk_find_entry(const char *string)
* smk_parse_smack - parse smack label from a text string
* @string: a text string that might contain a Smack label
* @len: the maximum size, or zero if it is NULL terminated.
* @smack: parsed smack label, or NULL if parse error
*
* Returns a pointer to the clean label, or NULL
*/
void smk_parse_smack(const char *string, int len, char *smack)
char *smk_parse_smack(const char *string, int len)
{
int found;
char *smack;
int i;
if (len <= 0 || len > SMK_MAXLEN)
len = SMK_MAXLEN;
if (len <= 0)
len = strlen(string) + 1;
for (i = 0, found = 0; i < SMK_LABELLEN; i++) {
if (found)
smack[i] = '\0';
else if (i >= len || string[i] > '~' || string[i] <= ' ' ||
string[i] == '/' || string[i] == '"' ||
string[i] == '\\' || string[i] == '\'') {
smack[i] = '\0';
found = 1;
} else
smack[i] = string[i];
/*
* Reserve a leading '-' as an indicator that
* this isn't a label, but an option to interfaces
* including /smack/cipso and /smack/cipso2
*/
if (string[0] == '-')
return NULL;
for (i = 0; i < len; i++)
if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
string[i] == '"' || string[i] == '\\' || string[i] == '\'')
break;
if (i == 0 || i >= SMK_LONGLABEL)
return NULL;
smack = kzalloc(i + 1, GFP_KERNEL);
if (smack != NULL) {
strncpy(smack, string, i + 1);
smack[i] = '\0';
}
return smack;
}
/**
* smk_netlbl_mls - convert a catset to netlabel mls categories
* @catset: the Smack categories
* @sap: where to put the netlabel categories
*
* Allocates and fills attr.mls
* Returns 0 on success, error code on failure.
*/
int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
int len)
{
unsigned char *cp;
unsigned char m;
int cat;
int rc;
int byte;
sap->flags |= NETLBL_SECATTR_MLS_CAT;
sap->attr.mls.lvl = level;
sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
sap->attr.mls.cat->startbit = 0;
for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
for (m = 0x80; m != 0; m >>= 1, cat++) {
if ((m & *cp) == 0)
continue;
rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
cat, GFP_ATOMIC);
if (rc < 0) {
netlbl_secattr_catmap_free(sap->attr.mls.cat);
return rc;
}
}
return 0;
}
/**
@ -390,33 +433,59 @@ void smk_parse_smack(const char *string, int len, char *smack)
struct smack_known *smk_import_entry(const char *string, int len)
{
struct smack_known *skp;
char smack[SMK_LABELLEN];
char *smack;
int slen;
int rc;
smk_parse_smack(string, len, smack);
if (smack[0] == '\0')
smack = smk_parse_smack(string, len);
if (smack == NULL)
return NULL;
mutex_lock(&smack_known_lock);
skp = smk_find_entry(smack);
if (skp != NULL)
goto freeout;
if (skp == NULL) {
skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
if (skp != NULL) {
strncpy(skp->smk_known, smack, SMK_MAXLEN);
skp->smk_secid = smack_next_secid++;
skp->smk_cipso = NULL;
INIT_LIST_HEAD(&skp->smk_rules);
spin_lock_init(&skp->smk_cipsolock);
mutex_init(&skp->smk_rules_lock);
/*
* Make sure that the entry is actually
* filled before putting it on the list.
*/
list_add_rcu(&skp->list, &smack_known_list);
}
skp = kzalloc(sizeof(*skp), GFP_KERNEL);
if (skp == NULL)
goto freeout;
skp->smk_known = smack;
skp->smk_secid = smack_next_secid++;
skp->smk_netlabel.domain = skp->smk_known;
skp->smk_netlabel.flags =
NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
/*
* If direct labeling works use it.
* Otherwise use mapped labeling.
*/
slen = strlen(smack);
if (slen < SMK_CIPSOLEN)
rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
&skp->smk_netlabel, slen);
else
rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
&skp->smk_netlabel, sizeof(skp->smk_secid));
if (rc >= 0) {
INIT_LIST_HEAD(&skp->smk_rules);
mutex_init(&skp->smk_rules_lock);
/*
* Make sure that the entry is actually
* filled before putting it on the list.
*/
list_add_rcu(&skp->list, &smack_known_list);
goto unlockout;
}
/*
* smk_netlbl_mls failed.
*/
kfree(skp);
skp = NULL;
freeout:
kfree(smack);
unlockout:
mutex_unlock(&smack_known_lock);
return skp;
@ -479,79 +548,9 @@ char *smack_from_secid(const u32 secid)
*/
u32 smack_to_secid(const char *smack)
{
struct smack_known *skp;
struct smack_known *skp = smk_find_entry(smack);
rcu_read_lock();
list_for_each_entry_rcu(skp, &smack_known_list, list) {
if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
rcu_read_unlock();
return skp->smk_secid;
}
}
rcu_read_unlock();
return 0;
}
/**
* smack_from_cipso - find the Smack label associated with a CIPSO option
* @level: Bell & LaPadula level from the network
* @cp: Bell & LaPadula categories from the network
*
* This is a simple lookup in the label table.
*
* Return the matching label from the label list or NULL.
*/
char *smack_from_cipso(u32 level, char *cp)
{
struct smack_known *kp;
char *final = NULL;
rcu_read_lock();
list_for_each_entry(kp, &smack_known_list, list) {
if (kp->smk_cipso == NULL)
continue;
spin_lock_bh(&kp->smk_cipsolock);
if (kp->smk_cipso->smk_level == level &&
memcmp(kp->smk_cipso->smk_catset, cp, SMK_LABELLEN) == 0)
final = kp->smk_known;
spin_unlock_bh(&kp->smk_cipsolock);
if (final != NULL)
break;
}
rcu_read_unlock();
return final;
}
/**
* smack_to_cipso - find the CIPSO option to go with a Smack label
* @smack: a pointer to the smack label in question
* @cp: where to put the result
*
* Returns zero if a value is available, non-zero otherwise.
*/
int smack_to_cipso(const char *smack, struct smack_cipso *cp)
{
struct smack_known *kp;
int found = 0;
rcu_read_lock();
list_for_each_entry_rcu(kp, &smack_known_list, list) {
if (kp->smk_known == smack ||
strcmp(kp->smk_known, smack) == 0) {
found = 1;
break;
}
}
rcu_read_unlock();
if (found == 0 || kp->smk_cipso == NULL)
return -ENOENT;
memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));
return 0;
if (skp == NULL)
return 0;
return skp->smk_secid;
}

185
security/smack/smack_lsm.c
View file

@ -30,7 +30,6 @@
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/pipe_fs_i.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <linux/audit.h>
#include <linux/magic.h>
@ -57,16 +56,23 @@
static char *smk_fetch(const char *name, struct inode *ip, struct dentry *dp)
{
int rc;
char in[SMK_LABELLEN];
char *buffer;
char *result = NULL;
if (ip->i_op->getxattr == NULL)
return NULL;
rc = ip->i_op->getxattr(dp, name, in, SMK_LABELLEN);
if (rc < 0)
buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
if (buffer == NULL)
return NULL;
return smk_import(in, rc);
rc = ip->i_op->getxattr(dp, name, buffer, SMK_LONGLABEL);
if (rc > 0)
result = smk_import(buffer, rc);
kfree(buffer);
return result;
}
/**
@ -825,7 +831,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
* check label validity here so import wont fail on
* post_setxattr
*/
if (size == 0 || size >= SMK_LABELLEN ||
if (size == 0 || size >= SMK_LONGLABEL ||
smk_import(value, size) == NULL)
rc = -EINVAL;
} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
@ -1823,65 +1829,6 @@ static char *smack_host_label(struct sockaddr_in *sip)
return NULL;
}
/**
* smack_set_catset - convert a capset to netlabel mls categories
* @catset: the Smack categories
* @sap: where to put the netlabel categories
*
* Allocates and fills attr.mls.cat
*/
static void smack_set_catset(char *catset, struct netlbl_lsm_secattr *sap)
{
unsigned char *cp;
unsigned char m;
int cat;
int rc;
int byte;
if (!catset)
return;
sap->flags |= NETLBL_SECATTR_MLS_CAT;
sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
sap->attr.mls.cat->startbit = 0;
for (cat = 1, cp = catset, byte = 0; byte < SMK_LABELLEN; cp++, byte++)
for (m = 0x80; m != 0; m >>= 1, cat++) {
if ((m & *cp) == 0)
continue;
rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
cat, GFP_ATOMIC);
}
}
/**
* smack_to_secattr - fill a secattr from a smack value
* @smack: the smack value
* @nlsp: where the result goes
*
* Casey says that CIPSO is good enough for now.
* It can be used to effect.
* It can also be abused to effect when necessary.
* Apologies to the TSIG group in general and GW in particular.
*/
static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
{
struct smack_cipso cipso;
int rc;
nlsp->domain = smack;
nlsp->flags = NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
rc = smack_to_cipso(smack, &cipso);
if (rc == 0) {
nlsp->attr.mls.lvl = cipso.smk_level;
smack_set_catset(cipso.smk_catset, nlsp);
} else {
nlsp->attr.mls.lvl = smack_cipso_direct;
smack_set_catset(smack, nlsp);
}
}
/**
* smack_netlabel - Set the secattr on a socket
* @sk: the socket
@ -1894,8 +1841,8 @@ static void smack_to_secattr(char *smack, struct netlbl_lsm_secattr *nlsp)
*/
static int smack_netlabel(struct sock *sk, int labeled)
{
struct smack_known *skp;
struct socket_smack *ssp = sk->sk_security;
struct netlbl_lsm_secattr secattr;
int rc = 0;
/*
@ -1913,10 +1860,8 @@ static int smack_netlabel(struct sock *sk, int labeled)
labeled == SMACK_UNLABELED_SOCKET)
netlbl_sock_delattr(sk);
else {
netlbl_secattr_init(&secattr);
smack_to_secattr(ssp->smk_out, &secattr);
rc = netlbl_sock_setattr(sk, sk->sk_family, &secattr);
netlbl_secattr_destroy(&secattr);
skp = smk_find_entry(ssp->smk_out);
rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel);
}
bh_unlock_sock(sk);
@ -1989,7 +1934,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
struct socket *sock;
int rc = 0;
if (value == NULL || size > SMK_LABELLEN || size == 0)
if (value == NULL || size > SMK_LONGLABEL || size == 0)
return -EACCES;
sp = smk_import(value, size);
@ -2785,7 +2730,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
if (!capable(CAP_MAC_ADMIN))
return -EPERM;
if (value == NULL || size == 0 || size >= SMK_LABELLEN)
if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
return -EINVAL;
if (strcmp(name, "current") != 0)
@ -2921,10 +2866,9 @@ static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
static char *smack_from_secattr(struct netlbl_lsm_secattr *sap,
struct socket_smack *ssp)
{
struct smack_known *skp;
char smack[SMK_LABELLEN];
struct smack_known *kp;
char *sp;
int pcat;
int found = 0;
if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
/*
@ -2932,59 +2876,27 @@ static char *smack_from_secattr(struct netlbl_lsm_secattr *sap,
* If there are flags but no level netlabel isn't
* behaving the way we expect it to.
*
* Get the categories, if any
* Look it up in the label table
* Without guidance regarding the smack value
* for the packet fall back on the network
* ambient value.
*/
memset(smack, '\0', SMK_LABELLEN);
if ((sap->flags & NETLBL_SECATTR_MLS_CAT) != 0)
for (pcat = -1;;) {
pcat = netlbl_secattr_catmap_walk(
sap->attr.mls.cat, pcat + 1);
if (pcat < 0)
break;
smack_catset_bit(pcat, smack);
}
/*
* If it is CIPSO using smack direct mapping
* we are already done. WeeHee.
*/
if (sap->attr.mls.lvl == smack_cipso_direct) {
/*
* The label sent is usually on the label list.
*
* If it is not we may still want to allow the
* delivery.
*
* If the recipient is accepting all packets
* because it is using the star ("*") label
* for SMACK64IPIN provide the web ("@") label
* so that a directed response will succeed.
* This is not very correct from a MAC point
* of view, but gets around the problem that
* locking prevents adding the newly discovered
* label to the list.
* The case where the recipient is not using
* the star label should obviously fail.
* The easy way to do this is to provide the
* star label as the subject label.
*/
skp = smk_find_entry(smack);
if (skp != NULL)
return skp->smk_known;
if (ssp != NULL &&
ssp->smk_in == smack_known_star.smk_known)
return smack_known_web.smk_known;
return smack_known_star.smk_known;
rcu_read_lock();
list_for_each_entry(kp, &smack_known_list, list) {
if (sap->attr.mls.lvl != kp->smk_netlabel.attr.mls.lvl)
continue;
if (memcmp(sap->attr.mls.cat,
kp->smk_netlabel.attr.mls.cat,
SMK_CIPSOLEN) != 0)
continue;
found = 1;
break;
}
/*
* Look it up in the supplied table if it is not
* a direct mapping.
*/
sp = smack_from_cipso(sap->attr.mls.lvl, smack);
if (sp != NULL)
return sp;
rcu_read_unlock();
if (found)
return kp->smk_known;
if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known)
return smack_known_web.smk_known;
return smack_known_star.smk_known;
@ -3184,11 +3096,13 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
u16 family = sk->sk_family;
struct smack_known *skp;
struct socket_smack *ssp = sk->sk_security;
struct netlbl_lsm_secattr secattr;
struct sockaddr_in addr;
struct iphdr *hdr;
char *sp;
char *hsp;
int rc;
struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
@ -3235,16 +3149,14 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
hdr = ip_hdr(skb);
addr.sin_addr.s_addr = hdr->saddr;
rcu_read_lock();
if (smack_host_label(&addr) == NULL) {
rcu_read_unlock();
netlbl_secattr_init(&secattr);
smack_to_secattr(sp, &secattr);
rc = netlbl_req_setattr(req, &secattr);
netlbl_secattr_destroy(&secattr);
} else {
rcu_read_unlock();
hsp = smack_host_label(&addr);
rcu_read_unlock();
if (hsp == NULL) {
skp = smk_find_entry(sp);
rc = netlbl_req_setattr(req, &skp->smk_netlabel);
} else
netlbl_req_delattr(req);
}
return rc;
}
@ -3668,15 +3580,6 @@ struct security_operations smack_ops = {
static __init void init_smack_known_list(void)
{
/*
* Initialize CIPSO locks
*/
spin_lock_init(&smack_known_huh.smk_cipsolock);
spin_lock_init(&smack_known_hat.smk_cipsolock);
spin_lock_init(&smack_known_star.smk_cipsolock);
spin_lock_init(&smack_known_floor.smk_cipsolock);
spin_lock_init(&smack_known_invalid.smk_cipsolock);
spin_lock_init(&smack_known_web.smk_cipsolock);
/*
* Initialize rule list locks
*/

1027
security/smack/smackfs.c
View file

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