There is a time where we need to calculate a context without the
inode having been created yet. To do this we take the negative dentry and
calculate a sid based on the process and the parent directory contexts.
Signed-off-by: David P. Quigley <dpquigl@xxxxxxxxxxxxx>
Signed-off-by: Matthew N. Dodd <Matthew.Dodd@xxxxxxxxxx>
---
include/linux/security.h | 11 +++++++++++
security/dummy.c | 7 +++++++
security/security.c | 9 +++++++++
security/selinux/hooks.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
4 files changed, 71 insertions(+), 2 deletions(-)
diff --git a/include/linux/security.h b/include/linux/security.h
index 8c0d687..6ccb010 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1240,6 +1240,8 @@ struct security_operations {
void (*sb_post_pivotroot) (struct nameidata * old_nd,
struct nameidata * new_nd);
+ int (*dentry_init_security) (struct dentry *dentry, int mode,
+ void **ctx, u32 *ctxlen);
int (*inode_alloc_security) (struct inode *inode);
void (*inode_free_security) (struct inode *inode);
int (*inode_init_security) (struct inode *inode, struct inode *dir,
@@ -1497,6 +1499,7 @@ void security_sb_post_mountroot(void);
void security_sb_post_addmount(struct vfsmount *mnt, struct nameidata *mountpoint_nd);
int security_sb_pivotroot(struct nameidata *old_nd, struct nameidata *new_nd);
void security_sb_post_pivotroot(struct nameidata *old_nd, struct nameidata *new_nd);
+int security_dentry_init_security(struct dentry *dentry, int mode, void **ctx, u32 *ctxlen);
int security_inode_alloc(struct inode *inode);
void security_inode_free(struct inode *inode);
int security_inode_init_security(struct inode *inode, struct inode *dir,
@@ -1793,6 +1796,14 @@ static inline void security_sb_post_pivotroot (struct nameidata *old_nd,
struct nameidata *new_nd)
{ }
+static inline int security_dentry_init_security(struct dentry *dentry,
+ int mode,
+ void **ctx,
+ u32 *ctxlen)
+{
+ return 0;
+}
+
static inline int security_inode_alloc (struct inode *inode)
{
return 0;
diff --git a/security/dummy.c b/security/dummy.c
index c2524ab..9a91650 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -245,6 +245,12 @@ static void dummy_sb_post_pivotroot (struct nameidata *old_nd, struct nameidata
return;
}
+static int dummy_dentry_init_security(struct dentry *dentry, int mode,
+ void **ctx, u32 *ctxlen)
+{
+ return -EOPNOTSUPP;
+}
+
static int dummy_inode_alloc_security (struct inode *inode)
{
return 0;
@@ -1003,6 +1009,7 @@ void security_fixup_ops (struct security_operations *ops)
set_to_dummy_if_null(ops, sb_post_addmount);
set_to_dummy_if_null(ops, sb_pivotroot);
set_to_dummy_if_null(ops, sb_post_pivotroot);
+ set_to_dummy_if_null(ops, dentry_init_security);
set_to_dummy_if_null(ops, inode_alloc_security);
set_to_dummy_if_null(ops, inode_free_security);
set_to_dummy_if_null(ops, inode_init_security);
diff --git a/security/security.c b/security/security.c
index cf853a7..c481405 100644
--- a/security/security.c
+++ b/security/security.c
@@ -308,6 +308,15 @@ void security_sb_post_pivotroot(struct nameidata *old_nd, struct nameidata *new_
security_ops->sb_post_pivotroot(old_nd, new_nd);
}
+int security_dentry_init_security(struct dentry *dentry,
+ int mode,
+ void **ctx,
+ u32 *ctxlen)
+{
+ return security_ops->dentry_init_security(dentry, mode, ctx, ctxlen);
+}
+EXPORT_SYMBOL(security_dentry_init_security);
+
int security_inode_alloc(struct inode *inode)
{
inode->i_security = NULL;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9083390..c9f5abc 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -60,6 +60,7 @@
#include <linux/udp.h>
#include <linux/dccp.h>
#include <linux/quota.h>
+#include <linux/fsnotify.h>
#include <linux/un.h> /* for Unix socket types */
#include <net/af_unix.h> /* for Unix socket types */
#include <linux/parser.h>
@@ -2086,6 +2087,42 @@ static int selinux_umount(struct vfsmount *mnt, int flags)
/* inode security operations */
+/*
+ * For now, we need a way to compute a SID for
+ * a dentry as the inode is not yet available
+ * (and under NFSv4 has no label backed by an EA anyway.
+ */
+static int selinux_dentry_init_security(struct dentry *dentry, int mode,
+ void **ctx, u32 *ctxlen)
+{
+ struct task_security_struct *tsec;
+ struct inode_security_struct *dsec;
+ struct superblock_security_struct *sbsec;
+ struct inode *dir = dentry->d_parent->d_inode;
+ u32 newsid;
+ int rc;
+
+ tsec = current->security;
+ dsec = dir->i_security;
+ sbsec = dir->i_sb->s_security;
+
+ if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) {
+ newsid = tsec->create_sid;
+ } else {
+ rc = security_transition_sid(tsec->sid, dsec->sid,
+ inode_mode_to_security_class(mode),
+ &newsid);
+ if (rc) {
+ printk(KERN_WARNING "%s: "
+ "security_transition_sid failed, rc=%d\n",
+ __FUNCTION__, -rc);
+ return rc;
+ }
+ }
+
+ return security_sid_to_context(newsid, (char **)ctx, ctxlen);
+}
+
static int selinux_inode_alloc_security(struct inode *inode)
{
return inode_alloc_security(inode);
@@ -2358,8 +2395,11 @@ static void selinux_inode_post_setxattr(struct dentry *dentry, char *name,
"%s, rc=%d\n", __FUNCTION__, (char*)value, -rc);
return;
}
-
+ isec->sclass = inode_mode_to_security_class(inode->i_mode);
isec->sid = newsid;
+ isec->initialized = 1;
+
+ fsnotify_change(dentry, ATTR_SECURITY_LABEL);
return;
}
@@ -2434,8 +2474,9 @@ static int selinux_inode_setsecurity(struct inode *inode, const char *name,
rc = security_context_to_sid((void*)value, size, &newsid);
if (rc)
return rc;
-
+ isec->sclass = inode_mode_to_security_class(inode->i_mode);
isec->sid = newsid;
+ isec->initialized = 1;
return 0;
}
@@ -4793,6 +4834,7 @@ static struct security_operations selinux_ops = {
.sb_mount = selinux_mount,
.sb_umount = selinux_umount,
+ .dentry_init_security = selinux_dentry_init_security,
.inode_alloc_security = selinux_inode_alloc_security,
.inode_free_security = selinux_inode_free_security,
.inode_init_security = selinux_inode_init_security,
--
1.5.3.4
--
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