smack: fixes for unlabeled host support
The following patch (against 2.6.29rc5) fixes a few issues in the
smack/netlabel "unlabeled host support" functionnality that was added in
2.6.29rc. It should go in before -final.
1) smack_host_label disregard a "0.0.0.0/0 @" rule (or other label),
preventing 'tagged' tasks to access Internet (many systems drop packets with
IP options)
2) netmasks were not handled correctly, they were stored in a way _not
equivalent_ to conversion to be32 (it was equivalent for /0, /8, /16, /24,
/32 masks but not other masks)
3) smack_netlbladdr prefixes (IP/mask) were not consistent (mask&IP was not
done), so there could have been different list entries for the same IP
prefix; if those entries had different labels, well ...
4) they were not sorted
1) 2) 3) are bugs, 4) is a more cosmetic issue.
The patch :
-creates a new helper smk_netlbladdr_insert to insert a smk_netlbladdr,
-sorted by netmask length
-use the new sorted nature of smack_netlbladdrs list to simplify
smack_host_label : the first match _will_ be the more specific
-corrects endianness issues in smk_write_netlbladdr & netlbladdr_seq_show
Signed-off-by: <etienne.basset@numericable.fr>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index fd8d1eb..a1b57e4 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -651,10 +651,6 @@
return skp;
}
-/*
-#define BEMASK 0x80000000
-*/
-#define BEMASK 0x00000001
#define BEBITS (sizeof(__be32) * 8)
/*
@@ -664,12 +660,10 @@
{
struct smk_netlbladdr *skp = (struct smk_netlbladdr *) v;
unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
- __be32 bebits;
- int maskn = 0;
+ int maskn;
+ u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
- for (bebits = BEMASK; bebits != 0; maskn++, bebits <<= 1)
- if ((skp->smk_mask.s_addr & bebits) == 0)
- break;
+ for (maskn = 0; temp_mask; temp_mask <<= 1, maskn++);
seq_printf(s, "%u.%u.%u.%u/%d %s\n",
hp[0], hp[1], hp[2], hp[3], maskn, skp->smk_label);
@@ -703,6 +697,42 @@
}
/**
+ * smk_netlbladdr_insert
+ * @new : netlabel to insert
+ *
+ * This helper insert netlabel in the smack_netlbladdrs list
+ * sorted by netmask length (longest to smallest)
+ */
+static void smk_netlbladdr_insert(struct smk_netlbladdr *new)
+{
+ struct smk_netlbladdr *m;
+
+ if (smack_netlbladdrs == NULL) {
+ smack_netlbladdrs = new;
+ return;
+ }
+
+ /* the comparison '>' is a bit hacky, but works */
+ if (new->smk_mask.s_addr > smack_netlbladdrs->smk_mask.s_addr) {
+ new->smk_next = smack_netlbladdrs;
+ smack_netlbladdrs = new;
+ return;
+ }
+ for (m = smack_netlbladdrs; m != NULL; m = m->smk_next) {
+ if (m->smk_next == NULL) {
+ m->smk_next = new;
+ return;
+ }
+ if (new->smk_mask.s_addr > m->smk_next->smk_mask.s_addr) {
+ new->smk_next = m->smk_next;
+ m->smk_next = new;
+ return;
+ }
+ }
+}
+
+
+/**
* smk_write_netlbladdr - write() for /smack/netlabel
* @file: file pointer, not actually used
* @buf: where to get the data from
@@ -725,8 +755,9 @@
struct netlbl_audit audit_info;
struct in_addr mask;
unsigned int m;
- __be32 bebits = BEMASK;
+ u32 mask_bits = (1<<31);
__be32 nsa;
+ u32 temp_mask;
/*
* Must have privilege.
@@ -762,10 +793,13 @@
if (sp == NULL)
return -EINVAL;
- for (mask.s_addr = 0; m > 0; m--) {
- mask.s_addr |= bebits;
- bebits <<= 1;
+ for (temp_mask = 0; m > 0; m--) {
+ temp_mask |= mask_bits;
+ mask_bits >>= 1;
}
+ mask.s_addr = cpu_to_be32(temp_mask);
+
+ newname.sin_addr.s_addr &= mask.s_addr;
/*
* Only allow one writer at a time. Writes should be
* quite rare and small in any case.
@@ -773,6 +807,7 @@
mutex_lock(&smk_netlbladdr_lock);
nsa = newname.sin_addr.s_addr;
+ /* try to find if the prefix is already in the list */
for (skp = smack_netlbladdrs; skp != NULL; skp = skp->smk_next)
if (skp->smk_host.sin_addr.s_addr == nsa &&
skp->smk_mask.s_addr == mask.s_addr)
@@ -788,9 +823,8 @@
rc = 0;
skp->smk_host.sin_addr.s_addr = newname.sin_addr.s_addr;
skp->smk_mask.s_addr = mask.s_addr;
- skp->smk_next = smack_netlbladdrs;
skp->smk_label = sp;
- smack_netlbladdrs = skp;
+ smk_netlbladdr_insert(skp);
}
} else {
rc = netlbl_cfg_unlbl_static_del(&init_net, NULL,