SELinux: Create a common helper to determine an inode label
Create a common helper function to determine the label for a new inode.
This is then used by:
- may_create()
- selinux_dentry_init_security()
- selinux_inode_init_security()
This will change the behaviour of the functions slightly, bringing them all
into line.
Suggested-by: Stephen Smalley <[email protected]>
Signed-off-by: David Howells <[email protected]>
---
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ffa5a642629a..902113d71acd 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1684,6 +1684,32 @@ out:
return rc;
}
+/*
+ * Determine the label for an inode that might be unioned.
+ */
+static int selinux_determine_inode_label(const struct inode *dir,
+ const struct qstr *name,
+ u16 tclass,
+ u32 *_new_isid)
+{
+ const struct superblock_security_struct *sbsec = dir->i_sb->s_security;
+ const struct inode_security_struct *dsec = dir->i_security;
+ const struct task_security_struct *tsec = current_security();
+
+ if ((sbsec->flags & SE_SBINITIALIZED) &&
+ (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
+ *_new_isid = sbsec->mntpoint_sid;
+ } else if ((sbsec->flags & SBLABEL_MNT) &&
+ tsec->create_sid) {
+ *_new_isid = tsec->create_sid;
+ } else {
+ return security_transition_sid(tsec->sid, dsec->sid, tclass,
+ name, _new_isid);
+ }
+
+ return 0;
+}
+
/* Check whether a task can create a file. */
static int may_create(struct inode *dir,
struct dentry *dentry,
@@ -1700,7 +1726,6 @@ static int may_create(struct inode *dir,
sbsec = dir->i_sb->s_security;
sid = tsec->sid;
- newsid = tsec->create_sid;
ad.type = LSM_AUDIT_DATA_DENTRY;
ad.u.dentry = dentry;
@@ -1711,12 +1736,10 @@ static int may_create(struct inode *dir,
if (rc)
return rc;
- if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
- rc = security_transition_sid(sid, dsec->sid, tclass,
- &dentry->d_name, &newsid);
- if (rc)
- return rc;
- }
+ rc = selinux_determine_inode_label(dir, &dentry->d_name, tclass,
+ &newsid);
+ if (rc)
+ return rc;
rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
if (rc)
@@ -2723,32 +2746,14 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode,
struct qstr *name, void **ctx,
u32 *ctxlen)
{
- const struct cred *cred = current_cred();
- struct task_security_struct *tsec;
- struct inode_security_struct *dsec;
- struct superblock_security_struct *sbsec;
- struct inode *dir = d_backing_inode(dentry->d_parent);
u32 newsid;
int rc;
- tsec = cred->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),
- name,
- &newsid);
- if (rc) {
- printk(KERN_WARNING
- "%s: security_transition_sid failed, rc=%d\n",
- __func__, -rc);
- return rc;
- }
- }
+ rc = selinux_determine_inode_label(d_inode(dentry), name,
+ inode_mode_to_security_class(mode),
+ &newsid);
+ if (rc)
+ return rc;
return security_sid_to_context(newsid, (char **)ctx, ctxlen);
}
@@ -2771,22 +2776,12 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
sid = tsec->sid;
newsid = tsec->create_sid;
- if ((sbsec->flags & SE_SBINITIALIZED) &&
- (sbsec->behavior == SECURITY_FS_USE_MNTPOINT))
- newsid = sbsec->mntpoint_sid;
- else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
- rc = security_transition_sid(sid, dsec->sid,
- inode_mode_to_security_class(inode->i_mode),
- qstr, &newsid);
- if (rc) {
- printk(KERN_WARNING "%s: "
- "security_transition_sid failed, rc=%d (dev=%s "
- "ino=%ld)\n",
- __func__,
- -rc, inode->i_sb->s_id, inode->i_ino);
- return rc;
- }
- }
+ rc = selinux_determine_inode_label(
+ dir, qstr,
+ inode_mode_to_security_class(inode->i_mode),
+ &newsid);
+ if (rc)
+ return rc;
/* Possibly defer initialization to selinux_complete_init. */
if (sbsec->flags & SE_SBINITIALIZED) {
On 06/18/2015 12:41 PM, David Howells wrote:
> SELinux: Create a common helper to determine an inode label
>
> Create a common helper function to determine the label for a new inode.
> This is then used by:
>
> - may_create()
> - selinux_dentry_init_security()
> - selinux_inode_init_security()
>
> This will change the behaviour of the functions slightly, bringing them all
> into line.
>
> Suggested-by: Stephen Smalley <[email protected]>
> Signed-off-by: David Howells <[email protected]>
> ---
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index ffa5a642629a..902113d71acd 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -1684,6 +1684,32 @@ out:
> return rc;
> }
>
> +/*
> + * Determine the label for an inode that might be unioned.
> + */
> +static int selinux_determine_inode_label(const struct inode *dir,
> + const struct qstr *name,
> + u16 tclass,
> + u32 *_new_isid)
> +{
> + const struct superblock_security_struct *sbsec = dir->i_sb->s_security;
> + const struct inode_security_struct *dsec = dir->i_security;
> + const struct task_security_struct *tsec = current_security();
> +
> + if ((sbsec->flags & SE_SBINITIALIZED) &&
> + (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
> + *_new_isid = sbsec->mntpoint_sid;
> + } else if ((sbsec->flags & SBLABEL_MNT) &&
> + tsec->create_sid) {
> + *_new_isid = tsec->create_sid;
> + } else {
> + return security_transition_sid(tsec->sid, dsec->sid, tclass,
> + name, _new_isid);
> + }
> +
> + return 0;
> +}
> +
> /* Check whether a task can create a file. */
> static int may_create(struct inode *dir,
> struct dentry *dentry,
> @@ -1700,7 +1726,6 @@ static int may_create(struct inode *dir,
> sbsec = dir->i_sb->s_security;
>
> sid = tsec->sid;
> - newsid = tsec->create_sid;
>
> ad.type = LSM_AUDIT_DATA_DENTRY;
> ad.u.dentry = dentry;
> @@ -1711,12 +1736,10 @@ static int may_create(struct inode *dir,
> if (rc)
> return rc;
>
> - if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
> - rc = security_transition_sid(sid, dsec->sid, tclass,
> - &dentry->d_name, &newsid);
> - if (rc)
> - return rc;
> - }
> + rc = selinux_determine_inode_label(dir, &dentry->d_name, tclass,
> + &newsid);
> + if (rc)
> + return rc;
>
> rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
> if (rc)
> @@ -2723,32 +2746,14 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode,
> struct qstr *name, void **ctx,
> u32 *ctxlen)
> {
> - const struct cred *cred = current_cred();
> - struct task_security_struct *tsec;
> - struct inode_security_struct *dsec;
> - struct superblock_security_struct *sbsec;
> - struct inode *dir = d_backing_inode(dentry->d_parent);
> u32 newsid;
> int rc;
>
> - tsec = cred->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),
> - name,
> - &newsid);
> - if (rc) {
> - printk(KERN_WARNING
> - "%s: security_transition_sid failed, rc=%d\n",
> - __func__, -rc);
> - return rc;
> - }
> - }
> + rc = selinux_determine_inode_label(d_inode(dentry), name,
We want d_inode(dentry->d_parent) here.
> + inode_mode_to_security_class(mode),
> + &newsid);
> + if (rc)
> + return rc;
>
> return security_sid_to_context(newsid, (char **)ctx, ctxlen);
> }
> @@ -2771,22 +2776,12 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
> sid = tsec->sid;
> newsid = tsec->create_sid;
>
> - if ((sbsec->flags & SE_SBINITIALIZED) &&
> - (sbsec->behavior == SECURITY_FS_USE_MNTPOINT))
> - newsid = sbsec->mntpoint_sid;
> - else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
> - rc = security_transition_sid(sid, dsec->sid,
> - inode_mode_to_security_class(inode->i_mode),
> - qstr, &newsid);
> - if (rc) {
> - printk(KERN_WARNING "%s: "
> - "security_transition_sid failed, rc=%d (dev=%s "
> - "ino=%ld)\n",
> - __func__,
> - -rc, inode->i_sb->s_id, inode->i_ino);
> - return rc;
> - }
> - }
> + rc = selinux_determine_inode_label(
> + dir, qstr,
> + inode_mode_to_security_class(inode->i_mode),
> + &newsid);
> + if (rc)
> + return rc;
>
> /* Possibly defer initialization to selinux_complete_init. */
> if (sbsec->flags & SE_SBINITIALIZED) {
>
>
On 06/18/2015 01:08 PM, Stephen Smalley wrote:
> On 06/18/2015 12:41 PM, David Howells wrote:
>> SELinux: Create a common helper to determine an inode label
>>
>> Create a common helper function to determine the label for a new inode.
>> This is then used by:
>>
>> - may_create()
>> - selinux_dentry_init_security()
>> - selinux_inode_init_security()
>>
>> This will change the behaviour of the functions slightly, bringing them all
>> into line.
>>
>> Suggested-by: Stephen Smalley <[email protected]>
>> Signed-off-by: David Howells <[email protected]>
>> ---
>> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
>> index ffa5a642629a..902113d71acd 100644
>> --- a/security/selinux/hooks.c
>> +++ b/security/selinux/hooks.c
>> @@ -1684,6 +1684,32 @@ out:
>> return rc;
>> }
>>
>> +/*
>> + * Determine the label for an inode that might be unioned.
>> + */
>> +static int selinux_determine_inode_label(const struct inode *dir,
>> + const struct qstr *name,
>> + u16 tclass,
>> + u32 *_new_isid)
>> +{
>> + const struct superblock_security_struct *sbsec = dir->i_sb->s_security;
>> + const struct inode_security_struct *dsec = dir->i_security;
>> + const struct task_security_struct *tsec = current_security();
>> +
>> + if ((sbsec->flags & SE_SBINITIALIZED) &&
>> + (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) {
>> + *_new_isid = sbsec->mntpoint_sid;
>> + } else if ((sbsec->flags & SBLABEL_MNT) &&
>> + tsec->create_sid) {
>> + *_new_isid = tsec->create_sid;
>> + } else {
>> + return security_transition_sid(tsec->sid, dsec->sid, tclass,
>> + name, _new_isid);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> /* Check whether a task can create a file. */
>> static int may_create(struct inode *dir,
>> struct dentry *dentry,
>> @@ -1700,7 +1726,6 @@ static int may_create(struct inode *dir,
>> sbsec = dir->i_sb->s_security;
>>
>> sid = tsec->sid;
>> - newsid = tsec->create_sid;
>>
>> ad.type = LSM_AUDIT_DATA_DENTRY;
>> ad.u.dentry = dentry;
>> @@ -1711,12 +1736,10 @@ static int may_create(struct inode *dir,
>> if (rc)
>> return rc;
>>
>> - if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
>> - rc = security_transition_sid(sid, dsec->sid, tclass,
>> - &dentry->d_name, &newsid);
>> - if (rc)
>> - return rc;
>> - }
>> + rc = selinux_determine_inode_label(dir, &dentry->d_name, tclass,
>> + &newsid);
>> + if (rc)
>> + return rc;
>>
>> rc = avc_has_perm(sid, newsid, tclass, FILE__CREATE, &ad);
>> if (rc)
>> @@ -2723,32 +2746,14 @@ static int selinux_dentry_init_security(struct dentry *dentry, int mode,
>> struct qstr *name, void **ctx,
>> u32 *ctxlen)
>> {
>> - const struct cred *cred = current_cred();
>> - struct task_security_struct *tsec;
>> - struct inode_security_struct *dsec;
>> - struct superblock_security_struct *sbsec;
>> - struct inode *dir = d_backing_inode(dentry->d_parent);
>> u32 newsid;
>> int rc;
>>
>> - tsec = cred->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),
>> - name,
>> - &newsid);
>> - if (rc) {
>> - printk(KERN_WARNING
>> - "%s: security_transition_sid failed, rc=%d\n",
>> - __func__, -rc);
>> - return rc;
>> - }
>> - }
>> + rc = selinux_determine_inode_label(d_inode(dentry), name,
>
> We want d_inode(dentry->d_parent) here.
Not sure why the caller didn't just pass in the dir inode in the first
place.
>
>> + inode_mode_to_security_class(mode),
>> + &newsid);
>> + if (rc)
>> + return rc;
>>
>> return security_sid_to_context(newsid, (char **)ctx, ctxlen);
>> }
>> @@ -2771,22 +2776,12 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
>> sid = tsec->sid;
>> newsid = tsec->create_sid;
>>
>> - if ((sbsec->flags & SE_SBINITIALIZED) &&
>> - (sbsec->behavior == SECURITY_FS_USE_MNTPOINT))
>> - newsid = sbsec->mntpoint_sid;
>> - else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) {
>> - rc = security_transition_sid(sid, dsec->sid,
>> - inode_mode_to_security_class(inode->i_mode),
>> - qstr, &newsid);
>> - if (rc) {
>> - printk(KERN_WARNING "%s: "
>> - "security_transition_sid failed, rc=%d (dev=%s "
>> - "ino=%ld)\n",
>> - __func__,
>> - -rc, inode->i_sb->s_id, inode->i_ino);
>> - return rc;
>> - }
>> - }
>> + rc = selinux_determine_inode_label(
>> + dir, qstr,
>> + inode_mode_to_security_class(inode->i_mode),
>> + &newsid);
>> + if (rc)
>> + return rc;
>>
>> /* Possibly defer initialization to selinux_complete_init. */
>> if (sbsec->flags & SE_SBINITIALIZED) {
>>
>>
>
Stephen Smalley <[email protected]> wrote:
> > + rc = selinux_determine_inode_label(d_inode(dentry), name,
>
> We want d_inode(dentry->d_parent) here.
Aargh. I forgot to commit it.
David
Stephen Smalley <[email protected]> wrote:
> >> + rc = selinux_determine_inode_label(d_inode(dentry), name,
> >
> > We want d_inode(dentry->d_parent) here.
>
> Not sure why the caller didn't just pass in the dir inode in the first
> place.
Might be something in one of the other LSMs?
David