diff options
author | etienne <etienne.basset@numericable.fr> | 2009-03-04 07:33:51 +0100 |
---|---|---|
committer | James Morris <jmorris@namei.org> | 2009-03-05 08:30:01 +1100 |
commit | 113a0e4590881ce579ca992a80ddc562b3372ede (patch) | |
tree | 29dd1cd1c5f594efb51cdf9530a90ba2f3f2854e /security/smack | |
parent | 454804ab0302b354e35d992d08e53fe03313baaf (diff) | |
download | linux-113a0e4590881ce579ca992a80ddc562b3372ede.tar.bz2 |
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>
Diffstat (limited to 'security/smack')
-rw-r--r-- | security/smack/smackfs.c | 64 |
1 files changed, 49 insertions, 15 deletions
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index fd8d1eb43700..a1b57e4dba3e 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -651,10 +651,6 @@ static void *netlbladdr_seq_next(struct seq_file *s, void *v, loff_t *pos) return skp; } -/* -#define BEMASK 0x80000000 -*/ -#define BEMASK 0x00000001 #define BEBITS (sizeof(__be32) * 8) /* @@ -664,12 +660,10 @@ static int netlbladdr_seq_show(struct seq_file *s, void *v) { 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 @@ static int smk_open_netlbladdr(struct inode *inode, struct file *file) } /** + * 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 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, 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 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, 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 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, 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 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, 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, |