smackfs: check for allocation failures in smk_set_access()
While adding a new subject/object pair to smack_list, smk_set_access()
didn't check the return of kzalloc().
This patch changes smk_set_access() to return 0 or -ENOMEM, based on
kzalloc()'s return. It also updates its caller, smk_write_load(), to
check for smk_set_access()'s return, given it is no longer a void
return function.
Signed-off-by: Sergio Luis <[email protected]>
To: Casey Schaufler <[email protected]>
Cc: Ahmed S. Darwish <[email protected]>
Cc: LSM <[email protected]>
Cc: LKLM <[email protected]>
security/smack/smackfs.c | 20 ++++++++++++++++----
1 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index c21d8c8..44eb933 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -185,11 +185,15 @@ static int smk_open_load(struct inode *inode, struct file *file)
* the subject/object pair and replaces the access that was
* there. If the pair isn't found add it with the specified
* access.
+ *
+ * Returns 0 if nothing goes wrong or -ENOMEM if it fails
+ * during the allocation of the new pair to add.
*/
-static void smk_set_access(struct smack_rule *srp)
+static int smk_set_access(struct smack_rule *srp)
{
struct smk_list_entry *sp;
struct smk_list_entry *newp;
+ int ret = 0;
mutex_lock(&smack_list_lock);
@@ -202,14 +206,20 @@ static void smk_set_access(struct smack_rule *srp)
if (sp == NULL) {
newp = kzalloc(sizeof(struct smk_list_entry), GFP_KERNEL);
+ if (newp == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
newp->smk_rule = *srp;
newp->smk_next = smack_list;
smack_list = newp;
}
+out:
mutex_unlock(&smack_list_lock);
- return;
+ return ret;
}
/**
@@ -309,8 +319,10 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
goto out;
}
- smk_set_access(&rule);
- rc = count;
+ rc = smk_set_access(&rule);
+
+ if (!rc)
+ rc = count;
out:
kfree(data);
Sergio Luis wrote:
> smackfs: check for allocation failures in smk_set_access()
>
> While adding a new subject/object pair to smack_list, smk_set_access()
> didn't check the return of kzalloc().
>
> This patch changes smk_set_access() to return 0 or -ENOMEM, based on
> kzalloc()'s return. It also updates its caller, smk_write_load(), to
> check for smk_set_access()'s return, given it is no longer a void
> return function.
>
> Signed-off-by: Sergio Luis <[email protected]>
> To: Casey Schaufler <[email protected]>
> Cc: Ahmed S. Darwish <[email protected]>
> Cc: LSM <[email protected]>
> Cc: LKLM <[email protected]>
>
Acked-by: Casey Schaufler <[email protected]>
> security/smack/smackfs.c | 20 ++++++++++++++++----
> 1 files changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
> index c21d8c8..44eb933 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -185,11 +185,15 @@ static int smk_open_load(struct inode *inode, struct file *file)
> * the subject/object pair and replaces the access that was
> * there. If the pair isn't found add it with the specified
> * access.
> + *
> + * Returns 0 if nothing goes wrong or -ENOMEM if it fails
> + * during the allocation of the new pair to add.
> */
> -static void smk_set_access(struct smack_rule *srp)
> +static int smk_set_access(struct smack_rule *srp)
> {
> struct smk_list_entry *sp;
> struct smk_list_entry *newp;
> + int ret = 0;
>
> mutex_lock(&smack_list_lock);
>
> @@ -202,14 +206,20 @@ static void smk_set_access(struct smack_rule *srp)
>
> if (sp == NULL) {
> newp = kzalloc(sizeof(struct smk_list_entry), GFP_KERNEL);
> + if (newp == NULL) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> newp->smk_rule = *srp;
> newp->smk_next = smack_list;
> smack_list = newp;
> }
>
> +out:
> mutex_unlock(&smack_list_lock);
>
> - return;
> + return ret;
> }
>
> /**
> @@ -309,8 +319,10 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
> goto out;
> }
>
> - smk_set_access(&rule);
> - rc = count;
> + rc = smk_set_access(&rule);
> +
> + if (!rc)
> + rc = count;
>
> out:
> kfree(data);
>
>
>
On Mon, 22 Dec 2008, Casey Schaufler wrote:
> Sergio Luis wrote:
> > smackfs: check for allocation failures in smk_set_access()
> > While adding a new subject/object pair to smack_list, smk_set_access()
> > didn't check the return of kzalloc().
> > This patch changes smk_set_access() to return 0 or -ENOMEM, based on
> > kzalloc()'s return. It also updates its caller, smk_write_load(), to
> > check for smk_set_access()'s return, given it is no longer a void return
> > function.
> >
> > Signed-off-by: Sergio Luis <[email protected]>
> > To: Casey Schaufler <[email protected]>
> > Cc: Ahmed S. Darwish <[email protected]>
> > Cc: LSM <[email protected]>
> > Cc: LKLM <[email protected]>
> >
>
> Acked-by: Casey Schaufler <[email protected]>
>
Applied to:
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next
I'll push this to Linus after he pulls the main security update, or with
it on re-send.
--
--
James Morris
<[email protected]>