From: Paul Moore paul@paul-moore.com
[ Upstream commit 200ea5a2292dc444a818b096ae6a32ba3caa51b9 ]
A previous fix, commit 83370b31a915 ("selinux: fix error initialization in inode_doinit_with_dentry()"), changed how failures were handled before a SELinux policy was loaded. Unfortunately that patch was potentially problematic for two reasons: it set the isec->initialized state without holding a lock, and it didn't set the inode's SELinux label to the "default" for the particular filesystem. The later can be a problem if/when a later attempt to revalidate the inode fails and SELinux reverts to the existing inode label.
This patch should restore the default inode labeling that existed before the original fix, without affecting the LABEL_INVALID marking such that revalidation will still be attempted in the future.
Fixes: 83370b31a915 ("selinux: fix error initialization in inode_doinit_with_dentry()") Reported-by: Sven Schnelle svens@linux.ibm.com Tested-by: Sven Schnelle svens@linux.ibm.com Reviewed-by: Ondrej Mosnacek omosnace@redhat.com Signed-off-by: Paul Moore paul@paul-moore.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/selinux/hooks.c | 31 +++++++++++++------------------ 1 file changed, 13 insertions(+), 18 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index af8ddae0ddedb..895d369bc4103 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1569,13 +1569,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent * inode_doinit with a dentry, before these inodes could * be used again by userspace. */ - isec->initialized = LABEL_INVALID; - /* - * There is nothing useful to jump to the "out" - * label, except a needless spin lock/unlock - * cycle. - */ - return 0; + goto out_invalid; }
len = INITCONTEXTLEN; @@ -1683,15 +1677,8 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent * inode_doinit() with a dentry, before these inodes * could be used again by userspace. */ - if (!dentry) { - isec->initialized = LABEL_INVALID; - /* - * There is nothing useful to jump to the "out" - * label, except a needless spin lock/unlock - * cycle. - */ - return 0; - } + if (!dentry) + goto out_invalid; rc = selinux_genfs_get_sid(dentry, sclass, sbsec->flags, &sid); dput(dentry); @@ -1704,11 +1691,10 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent out: spin_lock(&isec->lock); if (isec->initialized == LABEL_PENDING) { - if (!sid || rc) { + if (rc) { isec->initialized = LABEL_INVALID; goto out_unlock; } - isec->initialized = LABEL_INITIALIZED; isec->sid = sid; } @@ -1716,6 +1702,15 @@ out: out_unlock: spin_unlock(&isec->lock); return rc; + +out_invalid: + spin_lock(&isec->lock); + if (isec->initialized == LABEL_PENDING) { + isec->initialized = LABEL_INVALID; + isec->sid = sid; + } + spin_unlock(&isec->lock); + return 0; }
/* Convert a Linux signal to an access vector. */