smack: pass error code through pointers
This patch makes the following functions to use ERR_PTR() and related
macros to pass the appropriate error code through returned pointers:
smk_parse_smack()
smk_import_entry()
smk_fetch()
It also makes all the other functions that use them to handle the
error cases properly. This ways correct error codes from places
where they happened can be propagated to the user space if necessary.
Doing this it fixes a bug in onlycap and unconfined files
handling. Previously their content was cleared on any error from
smk_import_entry/smk_parse_smack, be it EINVAL (as originally intended)
or ENOMEM. Right now it only reacts on EINVAL passing other codes
properly to userspace.
Comments have been updated accordingly.
Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index f09b8c7..a143328 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -245,8 +245,8 @@
* @ip: a pointer to the inode
* @dp: a pointer to the dentry
*
- * Returns a pointer to the master list entry for the Smack label
- * or NULL if there was no label to fetch.
+ * Returns a pointer to the master list entry for the Smack label,
+ * NULL if there was no label to fetch, or an error code.
*/
static struct smack_known *smk_fetch(const char *name, struct inode *ip,
struct dentry *dp)
@@ -256,14 +256,18 @@
struct smack_known *skp = NULL;
if (ip->i_op->getxattr == NULL)
- return NULL;
+ return ERR_PTR(-EOPNOTSUPP);
buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
if (buffer == NULL)
- return NULL;
+ return ERR_PTR(-ENOMEM);
rc = ip->i_op->getxattr(dp, name, buffer, SMK_LONGLABEL);
- if (rc > 0)
+ if (rc < 0)
+ skp = ERR_PTR(rc);
+ else if (rc == 0)
+ skp = NULL;
+ else
skp = smk_import_entry(buffer, rc);
kfree(buffer);
@@ -605,40 +609,44 @@
if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
op += strlen(SMK_FSHAT);
skp = smk_import_entry(op, 0);
- if (skp != NULL) {
- sp->smk_hat = skp;
- specified = 1;
- }
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
+ sp->smk_hat = skp;
+ specified = 1;
+
} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
op += strlen(SMK_FSFLOOR);
skp = smk_import_entry(op, 0);
- if (skp != NULL) {
- sp->smk_floor = skp;
- specified = 1;
- }
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
+ sp->smk_floor = skp;
+ specified = 1;
+
} else if (strncmp(op, SMK_FSDEFAULT,
strlen(SMK_FSDEFAULT)) == 0) {
op += strlen(SMK_FSDEFAULT);
skp = smk_import_entry(op, 0);
- if (skp != NULL) {
- sp->smk_default = skp;
- specified = 1;
- }
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
+ sp->smk_default = skp;
+ specified = 1;
+
} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
op += strlen(SMK_FSROOT);
skp = smk_import_entry(op, 0);
- if (skp != NULL) {
- sp->smk_root = skp;
- specified = 1;
- }
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
+ sp->smk_root = skp;
+ specified = 1;
+
} else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
op += strlen(SMK_FSTRANS);
skp = smk_import_entry(op, 0);
- if (skp != NULL) {
- sp->smk_root = skp;
- transmute = 1;
- specified = 1;
- }
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
+ sp->smk_root = skp;
+ transmute = 1;
+ specified = 1;
}
}
@@ -1118,7 +1126,9 @@
if (rc == 0 && check_import) {
skp = size ? smk_import_entry(value, size) : NULL;
- if (skp == NULL || (check_star &&
+ if (IS_ERR(skp))
+ rc = PTR_ERR(skp);
+ else if (skp == NULL || (check_star &&
(skp == &smack_known_star || skp == &smack_known_web)))
rc = -EINVAL;
}
@@ -1158,19 +1168,19 @@
if (strcmp(name, XATTR_NAME_SMACK) == 0) {
skp = smk_import_entry(value, size);
- if (skp != NULL)
+ if (!IS_ERR(skp))
isp->smk_inode = skp;
else
isp->smk_inode = &smack_known_invalid;
} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
skp = smk_import_entry(value, size);
- if (skp != NULL)
+ if (!IS_ERR(skp))
isp->smk_task = skp;
else
isp->smk_task = &smack_known_invalid;
} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
skp = smk_import_entry(value, size);
- if (skp != NULL)
+ if (!IS_ERR(skp))
isp->smk_mmap = skp;
else
isp->smk_mmap = &smack_known_invalid;
@@ -2403,8 +2413,8 @@
return -EINVAL;
skp = smk_import_entry(value, size);
- if (skp == NULL)
- return -EINVAL;
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
nsp->smk_inode = skp;
@@ -3177,7 +3187,7 @@
*/
dp = dget(opt_dentry);
skp = smk_fetch(XATTR_NAME_SMACK, inode, dp);
- if (skp != NULL)
+ if (!IS_ERR_OR_NULL(skp))
final = skp;
/*
@@ -3214,11 +3224,14 @@
* Don't let the exec or mmap label be "*" or "@".
*/
skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
- if (skp == &smack_known_star || skp == &smack_known_web)
+ if (IS_ERR(skp) || skp == &smack_known_star ||
+ skp == &smack_known_web)
skp = NULL;
isp->smk_task = skp;
+
skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
- if (skp == &smack_known_star || skp == &smack_known_web)
+ if (IS_ERR(skp) || skp == &smack_known_star ||
+ skp == &smack_known_web)
skp = NULL;
isp->smk_mmap = skp;
@@ -3302,8 +3315,8 @@
return -EINVAL;
skp = smk_import_entry(value, size);
- if (skp == NULL)
- return -EINVAL;
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
/*
* No process is ever allowed the web ("@") label.
@@ -4078,8 +4091,10 @@
return -EINVAL;
skp = smk_import_entry(rulestr, 0);
- if (skp)
- *rule = skp->smk_known;
+ if (IS_ERR(skp))
+ return PTR_ERR(skp);
+
+ *rule = skp->smk_known;
return 0;
}