From 12b3052c3ee8f508b2c7ee4ddd63ed03423409d8 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 15 Nov 2010 18:36:29 -0500 Subject: capabilities/syslog: open code cap_syslog logic to fix build failure The addition of CONFIG_SECURITY_DMESG_RESTRICT resulted in a build failure when CONFIG_PRINTK=n. This is because the capabilities code which used the new option was built even though the variable in question didn't exist. The patch here fixes this by moving the capabilities checks out of the LSM and into the caller. All (known) LSMs should have been calling the capabilities hook already so it actually makes the code organization better to eliminate the hook altogether. Signed-off-by: Eric Paris Acked-by: James Morris Signed-off-by: Linus Torvalds --- security/security.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'security/security.c') diff --git a/security/security.c b/security/security.c index 3ef5e2a7a741..1b798d3df710 100644 --- a/security/security.c +++ b/security/security.c @@ -197,9 +197,9 @@ int security_quota_on(struct dentry *dentry) return security_ops->quota_on(dentry); } -int security_syslog(int type, bool from_file) +int security_syslog(int type) { - return security_ops->syslog(type, from_file); + return security_ops->syslog(type); } int security_settime(struct timespec *ts, struct timezone *tz) -- cgit v1.2.3 From 3610cda53f247e176bcbb7a7cca64bc53b12acdb Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 5 Jan 2011 15:38:53 -0800 Subject: af_unix: Avoid socket->sk NULL OOPS in stream connect security hooks. unix_release() can asynchornously set socket->sk to NULL, and it does so without holding the unix_state_lock() on "other" during stream connects. However, the reverse mapping, sk->sk_socket, is only transitioned to NULL under the unix_state_lock(). Therefore make the security hooks follow the reverse mapping instead of the forward mapping. Reported-by: Jeremy Fitzhardinge Reported-by: Linus Torvalds Signed-off-by: David S. Miller --- security/security.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'security/security.c') diff --git a/security/security.c b/security/security.c index 1b798d3df710..e5fb07a3052d 100644 --- a/security/security.c +++ b/security/security.c @@ -977,8 +977,7 @@ EXPORT_SYMBOL(security_inode_getsecctx); #ifdef CONFIG_SECURITY_NETWORK -int security_unix_stream_connect(struct socket *sock, struct socket *other, - struct sock *newsk) +int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk) { return security_ops->unix_stream_connect(sock, other, newsk); } -- cgit v1.2.3 From 31e6b01f4183ff419a6d1f86177cbf4662347cec Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 7 Jan 2011 17:49:52 +1100 Subject: fs: rcu-walk for path lookup Perform common cases of path lookups without any stores or locking in the ancestor dentry elements. This is called rcu-walk, as opposed to the current algorithm which is a refcount based walk, or ref-walk. This results in far fewer atomic operations on every path element, significantly improving path lookup performance. It also avoids cacheline bouncing on common dentries, significantly improving scalability. The overall design is like this: * LOOKUP_RCU is set in nd->flags, which distinguishes rcu-walk from ref-walk. * Take the RCU lock for the entire path walk, starting with the acquiring of the starting path (eg. root/cwd/fd-path). So now dentry refcounts are not required for dentry persistence. * synchronize_rcu is called when unregistering a filesystem, so we can access d_ops and i_ops during rcu-walk. * Similarly take the vfsmount lock for the entire path walk. So now mnt refcounts are not required for persistence. Also we are free to perform mount lookups, and to assume dentry mount points and mount roots are stable up and down the path. * Have a per-dentry seqlock to protect the dentry name, parent, and inode, so we can load this tuple atomically, and also check whether any of its members have changed. * Dentry lookups (based on parent, candidate string tuple) recheck the parent sequence after the child is found in case anything changed in the parent during the path walk. * inode is also RCU protected so we can load d_inode and use the inode for limited things. * i_mode, i_uid, i_gid can be tested for exec permissions during path walk. * i_op can be loaded. When we reach the destination dentry, we lock it, recheck lookup sequence, and increment its refcount and mountpoint refcount. RCU and vfsmount locks are dropped. This is termed "dropping rcu-walk". If the dentry refcount does not match, we can not drop rcu-walk gracefully at the current point in the lokup, so instead return -ECHILD (for want of a better errno). This signals the path walking code to re-do the entire lookup with a ref-walk. Aside from the final dentry, there are other situations that may be encounted where we cannot continue rcu-walk. In that case, we drop rcu-walk (ie. take a reference on the last good dentry) and continue with a ref-walk. Again, if we can drop rcu-walk gracefully, we return -ECHILD and do the whole lookup using ref-walk. But it is very important that we can continue with ref-walk for most cases, particularly to avoid the overhead of double lookups, and to gain the scalability advantages on common path elements (like cwd and root). The cases where rcu-walk cannot continue are: * NULL dentry (ie. any uncached path element) * parent with d_inode->i_op->permission or ACLs * dentries with d_revalidate * Following links In future patches, permission checks and d_revalidate become rcu-walk aware. It may be possible eventually to make following links rcu-walk aware. Uncached path elements will always require dropping to ref-walk mode, at the very least because i_mutex needs to be grabbed, and objects allocated. Signed-off-by: Nick Piggin --- security/security.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'security/security.c') diff --git a/security/security.c b/security/security.c index 1b798d3df710..c645e263ca8d 100644 --- a/security/security.c +++ b/security/security.c @@ -513,6 +513,15 @@ int security_inode_permission(struct inode *inode, int mask) return security_ops->inode_permission(inode, mask); } +int security_inode_exec_permission(struct inode *inode, unsigned int flags) +{ + if (unlikely(IS_PRIVATE(inode))) + return 0; + if (flags) + return -ECHILD; + return security_ops->inode_permission(inode, MAY_EXEC); +} + int security_inode_setattr(struct dentry *dentry, struct iattr *attr) { if (unlikely(IS_PRIVATE(dentry->d_inode))) -- cgit v1.2.3