On 10/26/2015 05:15 PM, Andreas Gruenbacher wrote:
Add functions dentry_security and inode_security for accessing
inode->i_security. These functions initially don't do much, but they
will later be used to revalidate the security labels when necessary.
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
security/selinux/hooks.c | 101 ++++++++++++++++++++++++++---------------------
1 file changed, 57 insertions(+), 44 deletions(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index fc8f626..65e8689 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -241,6 +241,24 @@ static int inode_alloc_security(struct inode *inode)
return 0;
}
+/*
+ * Get the security label of a dentry's inode.
+ */
+static struct inode_security_struct *dentry_security(struct dentry *dentry)
+{
+ struct inode *inode = d_backing_inode(dentry);
+
+ return inode->i_security;
+}
+
+/*
+ * Get the security label of an inode.
+ */
+static struct inode_security_struct *inode_security(struct inode *inode)
+{
+ return inode->i_security;
+}
+
static void inode_free_rcu(struct rcu_head *head)
{
struct inode_security_struct *isec;
<snip>
@@ -2207,7 +2222,6 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
struct task_security_struct *new_tsec;
struct inode_security_struct *isec;
struct common_audit_data ad;
- struct inode *inode = file_inode(bprm->file);
int rc;
/* SELinux context only depends on initial program or script and not
@@ -2217,7 +2231,7 @@ static int selinux_bprm_set_creds(struct linux_binprm *bprm)
old_tsec = current_security();
new_tsec = bprm->cred->security;
- isec = inode->i_security;
+ isec = dentry_security(bprm->file->f_path.dentry);
IIUC, this could change which inode label gets used when using overlayfs
(the overlay inode or the underlying inode). Not sure whether the
current code is correct for overlayfs (overlayfs + SELinux support still
in progress).
@@ -3154,7 +3168,7 @@ out_nofree:
static int selinux_inode_setsecurity(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
- struct inode_security_struct *isec = inode->i_security;
+ struct inode_security_struct *isec = inode_security(inode);
Was it intentional to not do this for selinux_inode_getsecurity() and
selinux_inode_getsecid()?
@@ -3241,8 +3254,8 @@ int ioctl_has_perm(const struct cred *cred, struct file *file,
{
struct common_audit_data ad;
struct file_security_struct *fsec = file->f_security;
- struct inode *inode = file_inode(file);
- struct inode_security_struct *isec = inode->i_security;
+ struct dentry *dentry = file->f_path.dentry;
+ struct inode_security_struct *isec = dentry_security(dentry);
struct lsm_ioctlop_audit ioctl;
u32 ssid = cred_sid(cred);
int rc;
@@ -3263,7 +3276,7 @@ int ioctl_has_perm(const struct cred *cred, struct file *file,
goto out;
}
- if (unlikely(IS_PRIVATE(inode)))
+ if (unlikely(IS_PRIVATE(dentry->d_inode)))
return 0;
rc = avc_has_extended_perms(ssid, isec->sid, isec->sclass,
@@ -3506,7 +3519,7 @@ static int selinux_file_open(struct file *file, const struct cred *cred)
struct inode_security_struct *isec;
fsec = file->f_security;
- isec = file_inode(file)->i_security;
+ isec = dentry_security(file->f_path.dentry);
Similarly for these cases, switching from file_inode(file) to
d_backing_inode(dentry) could affect overlayfs interaction IIUC. cc'd
David for clarification.
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