Smack: recursive tramsmute
The transmuting directory feature of Smack requires that
the transmuting attribute be explicitly set in all cases.
It seems the users of this facility would expect that the
transmuting attribute be inherited by subdirectories that
are created in a transmuting directory. This does not seem
to add any additional complexity to the understanding of
how the system works.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 4ede719..cf2594d 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -66,6 +66,7 @@
#define SMK_INODE_INSTANT 0x01 /* inode is instantiated */
#define SMK_INODE_TRANSMUTE 0x02 /* directory is transmuting */
+#define SMK_INODE_CHANGED 0x04 /* smack was transmuted */
/*
* A label access rule.
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 45c32f0..df45d39 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -556,6 +556,7 @@
void **value, size_t *len)
{
struct smack_known *skp;
+ struct inode_smack *issp = inode->i_security;
char *csp = smk_of_current();
char *isp = smk_of_inode(inode);
char *dsp = smk_of_inode(dir);
@@ -577,10 +578,13 @@
* If the access rule allows transmutation and
* the directory requests transmutation then
* by all means transmute.
+ * Mark the inode as changed.
*/
if (may > 0 && ((may & MAY_TRANSMUTE) != 0) &&
- smk_inode_transmutable(dir))
+ smk_inode_transmutable(dir)) {
isp = dsp;
+ issp->smk_flags |= SMK_INODE_CHANGED;
+ }
*value = kstrdup(isp, GFP_KERNEL);
if (*value == NULL)
@@ -2552,6 +2556,7 @@
char *final;
char trattr[TRANS_TRUE_SIZE];
int transflag = 0;
+ int rc;
struct dentry *dp;
if (inode == NULL)
@@ -2670,17 +2675,38 @@
*/
dp = dget(opt_dentry);
fetched = smk_fetch(XATTR_NAME_SMACK, inode, dp);
- if (fetched != NULL) {
+ if (fetched != NULL)
final = fetched;
- if (S_ISDIR(inode->i_mode)) {
- trattr[0] = '\0';
- inode->i_op->getxattr(dp,
+
+ /*
+ * Transmuting directory
+ */
+ if (S_ISDIR(inode->i_mode)) {
+ /*
+ * If this is a new directory and the label was
+ * transmuted when the inode was initialized
+ * set the transmute attribute on the directory
+ * and mark the inode.
+ *
+ * If there is a transmute attribute on the
+ * directory mark the inode.
+ */
+ if (isp->smk_flags & SMK_INODE_CHANGED) {
+ isp->smk_flags &= ~SMK_INODE_CHANGED;
+ rc = inode->i_op->setxattr(dp,
XATTR_NAME_SMACKTRANSMUTE,
- trattr, TRANS_TRUE_SIZE);
- if (strncmp(trattr, TRANS_TRUE,
- TRANS_TRUE_SIZE) == 0)
- transflag = SMK_INODE_TRANSMUTE;
+ TRANS_TRUE, TRANS_TRUE_SIZE,
+ 0);
+ } else {
+ rc = inode->i_op->getxattr(dp,
+ XATTR_NAME_SMACKTRANSMUTE, trattr,
+ TRANS_TRUE_SIZE);
+ if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
+ TRANS_TRUE_SIZE) != 0)
+ rc = -EINVAL;
}
+ if (rc >= 0)
+ transflag = SMK_INODE_TRANSMUTE;
}
isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
isp->smk_mmap = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);