selinux: Convert isec->lock into a spinlock
Convert isec->lock from a mutex into a spinlock. Instead of holding the lock while sleeping in inode_doinit_with_dentry, set isec->initialized to LABEL_PENDING and release the lock. Then, when the sid has been determined, re-acquire the lock. If isec->initialized is still set to LABEL_PENDING, set isec->sid; otherwise, the sid has been set by another task (LABEL_INITIALIZED) or invalidated (LABEL_INVALID) in the meantime. This fixes a deadlock on gfs2 where * one task is in inode_doinit_with_dentry -> gfs2_getxattr, holds isec->lock, and tries to acquire the inode's glock, and * another task is in do_xmote -> inode_go_inval -> selinux_inode_invalidate_secctx, holds the inode's glock, and tries to acquire isec->lock. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> [PM: minor tweaks to keep checkpatch.pl happy] Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Andreas Gruenbacher
Paul Moore
Родитель
3322d0d64f
Коммит
9287aed2ad
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@ -231,7 +231,7 @@ static int inode_alloc_security(struct inode *inode)
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if (!isec)
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return -ENOMEM;
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mutex_init(&isec->lock);
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spin_lock_init(&isec->lock);
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INIT_LIST_HEAD(&isec->list);
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isec->inode = inode;
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isec->sid = SECINITSID_UNLABELED;
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@ -1382,7 +1382,8 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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{
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struct superblock_security_struct *sbsec = NULL;
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struct inode_security_struct *isec = inode->i_security;
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u32 sid;
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u32 task_sid, sid = 0;
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u16 sclass;
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struct dentry *dentry;
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#define INITCONTEXTLEN 255
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char *context = NULL;
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@ -1392,7 +1393,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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if (isec->initialized == LABEL_INITIALIZED)
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return 0;
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mutex_lock(&isec->lock);
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spin_lock(&isec->lock);
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if (isec->initialized == LABEL_INITIALIZED)
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goto out_unlock;
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@ -1411,12 +1412,18 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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goto out_unlock;
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}
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sclass = isec->sclass;
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task_sid = isec->task_sid;
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sid = isec->sid;
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isec->initialized = LABEL_PENDING;
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spin_unlock(&isec->lock);
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switch (sbsec->behavior) {
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case SECURITY_FS_USE_NATIVE:
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break;
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case SECURITY_FS_USE_XATTR:
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if (!(inode->i_opflags & IOP_XATTR)) {
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isec->sid = sbsec->def_sid;
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sid = sbsec->def_sid;
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break;
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}
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/* Need a dentry, since the xattr API requires one.
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@ -1438,7 +1445,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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* inode_doinit with a dentry, before these inodes could
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* be used again by userspace.
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*/
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goto out_unlock;
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goto out;
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}
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len = INITCONTEXTLEN;
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@ -1446,7 +1453,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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if (!context) {
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rc = -ENOMEM;
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dput(dentry);
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goto out_unlock;
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goto out;
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}
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context[len] = '\0';
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rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
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@ -1457,14 +1464,14 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, NULL, 0);
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if (rc < 0) {
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dput(dentry);
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goto out_unlock;
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goto out;
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}
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len = rc;
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context = kmalloc(len+1, GFP_NOFS);
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if (!context) {
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rc = -ENOMEM;
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dput(dentry);
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goto out_unlock;
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goto out;
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}
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context[len] = '\0';
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rc = __vfs_getxattr(dentry, inode, XATTR_NAME_SELINUX, context, len);
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@ -1476,7 +1483,7 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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"%d for dev=%s ino=%ld\n", __func__,
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-rc, inode->i_sb->s_id, inode->i_ino);
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kfree(context);
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goto out_unlock;
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goto out;
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}
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/* Map ENODATA to the default file SID */
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sid = sbsec->def_sid;
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@ -1506,28 +1513,25 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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}
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}
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kfree(context);
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isec->sid = sid;
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break;
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case SECURITY_FS_USE_TASK:
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isec->sid = isec->task_sid;
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sid = task_sid;
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break;
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case SECURITY_FS_USE_TRANS:
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/* Default to the fs SID. */
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isec->sid = sbsec->sid;
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sid = sbsec->sid;
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/* Try to obtain a transition SID. */
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rc = security_transition_sid(isec->task_sid, sbsec->sid,
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isec->sclass, NULL, &sid);
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rc = security_transition_sid(task_sid, sid, sclass, NULL, &sid);
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if (rc)
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goto out_unlock;
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isec->sid = sid;
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goto out;
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break;
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case SECURITY_FS_USE_MNTPOINT:
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isec->sid = sbsec->mntpoint_sid;
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sid = sbsec->mntpoint_sid;
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break;
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default:
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/* Default to the fs superblock SID. */
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isec->sid = sbsec->sid;
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sid = sbsec->sid;
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if ((sbsec->flags & SE_SBGENFS) && !S_ISLNK(inode->i_mode)) {
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/* We must have a dentry to determine the label on
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@ -1550,21 +1554,30 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
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* could be used again by userspace.
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*/
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if (!dentry)
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goto out_unlock;
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rc = selinux_genfs_get_sid(dentry, isec->sclass,
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goto out;
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rc = selinux_genfs_get_sid(dentry, sclass,
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sbsec->flags, &sid);
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dput(dentry);
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if (rc)
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goto out_unlock;
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isec->sid = sid;
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goto out;
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}
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break;
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}
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out:
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spin_lock(&isec->lock);
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if (isec->initialized == LABEL_PENDING) {
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if (!sid || rc) {
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isec->initialized = LABEL_INVALID;
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goto out_unlock;
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}
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isec->initialized = LABEL_INITIALIZED;
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isec->sid = sid;
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}
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out_unlock:
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mutex_unlock(&isec->lock);
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spin_unlock(&isec->lock);
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return rc;
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}
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@ -3195,9 +3208,11 @@ static void selinux_inode_post_setxattr(struct dentry *dentry, const char *name,
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}
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isec = backing_inode_security(dentry);
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spin_lock(&isec->lock);
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isec->sclass = inode_mode_to_security_class(inode->i_mode);
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isec->sid = newsid;
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isec->initialized = LABEL_INITIALIZED;
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spin_unlock(&isec->lock);
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return;
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}
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@ -3290,9 +3305,11 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
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if (rc)
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return rc;
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spin_lock(&isec->lock);
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isec->sclass = inode_mode_to_security_class(inode->i_mode);
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isec->sid = newsid;
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isec->initialized = LABEL_INITIALIZED;
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spin_unlock(&isec->lock);
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return 0;
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}
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@ -3953,9 +3970,11 @@ static void selinux_task_to_inode(struct task_struct *p,
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struct inode_security_struct *isec = inode->i_security;
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u32 sid = task_sid(p);
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spin_lock(&isec->lock);
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isec->sclass = inode_mode_to_security_class(inode->i_mode);
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isec->sid = sid;
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isec->initialized = LABEL_INITIALIZED;
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spin_unlock(&isec->lock);
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}
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/* Returns error only if unable to parse addresses */
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@ -4274,24 +4293,24 @@ static int selinux_socket_post_create(struct socket *sock, int family,
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const struct task_security_struct *tsec = current_security();
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struct inode_security_struct *isec = inode_security_novalidate(SOCK_INODE(sock));
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struct sk_security_struct *sksec;
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u16 sclass = socket_type_to_security_class(family, type, protocol);
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u32 sid = SECINITSID_KERNEL;
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int err = 0;
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isec->sclass = socket_type_to_security_class(family, type, protocol);
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if (kern)
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isec->sid = SECINITSID_KERNEL;
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else {
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err = socket_sockcreate_sid(tsec, isec->sclass, &(isec->sid));
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if (!kern) {
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err = socket_sockcreate_sid(tsec, sclass, &sid);
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if (err)
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return err;
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}
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isec->sclass = sclass;
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isec->sid = sid;
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isec->initialized = LABEL_INITIALIZED;
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if (sock->sk) {
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sksec = sock->sk->sk_security;
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sksec->sid = isec->sid;
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sksec->sclass = isec->sclass;
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sksec->sclass = sclass;
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sksec->sid = sid;
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err = selinux_netlbl_socket_post_create(sock->sk, family);
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}
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@ -4467,16 +4486,22 @@ static int selinux_socket_accept(struct socket *sock, struct socket *newsock)
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int err;
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struct inode_security_struct *isec;
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struct inode_security_struct *newisec;
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u16 sclass;
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u32 sid;
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err = sock_has_perm(current, sock->sk, SOCKET__ACCEPT);
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if (err)
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return err;
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newisec = inode_security_novalidate(SOCK_INODE(newsock));
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isec = inode_security_novalidate(SOCK_INODE(sock));
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newisec->sclass = isec->sclass;
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newisec->sid = isec->sid;
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spin_lock(&isec->lock);
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sclass = isec->sclass;
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sid = isec->sid;
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spin_unlock(&isec->lock);
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newisec = inode_security_novalidate(SOCK_INODE(newsock));
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newisec->sclass = sclass;
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newisec->sid = sid;
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newisec->initialized = LABEL_INITIALIZED;
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return 0;
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@ -5979,9 +6004,9 @@ static void selinux_inode_invalidate_secctx(struct inode *inode)
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{
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struct inode_security_struct *isec = inode->i_security;
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mutex_lock(&isec->lock);
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spin_lock(&isec->lock);
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isec->initialized = LABEL_INVALID;
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mutex_unlock(&isec->lock);
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spin_unlock(&isec->lock);
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}
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/*
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@ -39,7 +39,8 @@ struct task_security_struct {
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enum label_initialized {
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LABEL_INVALID, /* invalid or not initialized */
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LABEL_INITIALIZED /* initialized */
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LABEL_INITIALIZED, /* initialized */
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LABEL_PENDING
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};
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struct inode_security_struct {
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@ -52,7 +53,7 @@ struct inode_security_struct {
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u32 sid; /* SID of this object */
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u16 sclass; /* security class of this object */
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unsigned char initialized; /* initialization flag */
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struct mutex lock;
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spinlock_t lock;
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};
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struct file_security_struct {
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