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authorCasey Schaufler <casey@schaufler-ca.com>2012-03-13 19:14:19 -0700
committerCasey Schaufler <cschaufler@vaio-ubuntu.(none)>2012-05-14 22:45:17 -0700
commit2267b13a7cad1f9dfe0073c1f902d45953f9faff (patch)
treec0797ecce868fe590ac46a5d511a2f3812de15d1 /security/smack
parent2cc8a71641b4460783ea3bd7a3476043fdf85397 (diff)
downloadvexpress-lsk-2267b13a7cad1f9dfe0073c1f902d45953f9faff.tar.gz
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>
Diffstat (limited to 'security/smack')
-rw-r--r--security/smack/smack.h1
-rw-r--r--security/smack/smack_lsm.c44
2 files changed, 36 insertions, 9 deletions
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 4ede719922e..cf2594dfa93 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -66,6 +66,7 @@ struct task_smack {
#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 45c32f07416..df45d393918 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -556,6 +556,7 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
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 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
* 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 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
char *final;
char trattr[TRANS_TRUE_SIZE];
int transflag = 0;
+ int rc;
struct dentry *dp;
if (inode == NULL)
@@ -2670,17 +2675,38 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
*/
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);