From 211a40c0870457b29100cffea0180fa5083caf96 Mon Sep 17 00:00:00 2001 From: etienne Date: Wed, 4 Mar 2009 07:33:51 +0100 Subject: 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: Acked-by: Casey Schaufler Reviewed-by: Paul Moore Signed-off-by: James Morris --- security/smack/smack_lsm.c | 43 ++++++++----------------------------------- 1 file changed, 8 insertions(+), 35 deletions(-) (limited to 'security/smack/smack_lsm.c') diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 0278bc083044..e7ded1326b0f 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -1498,58 +1498,31 @@ static int smack_socket_post_create(struct socket *sock, int family, * looks for host based access restrictions * * This version will only be appropriate for really small - * sets of single label hosts. Because of the masking - * it cannot shortcut out on the first match. There are - * numerious ways to address the problem, but none of them - * have been applied here. + * sets of single label hosts. * * Returns the label of the far end or NULL if it's not special. */ static char *smack_host_label(struct sockaddr_in *sip) { struct smk_netlbladdr *snp; - char *bestlabel = NULL; struct in_addr *siap = &sip->sin_addr; - struct in_addr *liap; - struct in_addr *miap; - struct in_addr bestmask; if (siap->s_addr == 0) return NULL; - bestmask.s_addr = 0; - for (snp = smack_netlbladdrs; snp != NULL; snp = snp->smk_next) { - liap = &snp->smk_host.sin_addr; - miap = &snp->smk_mask; - /* - * If the addresses match after applying the list entry mask - * the entry matches the address. If it doesn't move along to - * the next entry. - */ - if ((liap->s_addr & miap->s_addr) != - (siap->s_addr & miap->s_addr)) - continue; /* - * If the list entry mask identifies a single address - * it can't get any more specific. + * we break after finding the first match because + * the list is sorted from longest to shortest mask + * so we have found the most specific match */ - if (miap->s_addr == 0xffffffff) + if ((&snp->smk_host.sin_addr)->s_addr == + (siap->s_addr & (&snp->smk_mask)->s_addr)) { return snp->smk_label; - /* - * If the list entry mask is less specific than the best - * already found this entry is uninteresting. - */ - if ((miap->s_addr | bestmask.s_addr) == bestmask.s_addr) - continue; - /* - * This is better than any entry found so far. - */ - bestmask.s_addr = miap->s_addr; - bestlabel = snp->smk_label; + } } - return bestlabel; + return NULL; } /** -- cgit v1.2.3