2018-05-27 22:15:32

by Colin King

Subject: [PATCH][next] EVM: fix memory leak of temporary buffer 'temp'

From: Colin Ian King <[email protected]>

The allocation of 'temp' is not kfree'd and hence there is a memory
leak on each call of evm_read_xattrs. Fix this by kfree'ing it
after copying data from it back to the user space buffer 'buf'.

Detected by CoverityScan, CID#1469386 ("Resource Leak")

Fixes: fa516b66a1bf ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Colin Ian King <[email protected]>
---
security/integrity/evm/evm_secfs.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index a7a0a1acae99..fb8bc950aceb 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -158,6 +158,8 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
mutex_unlock(&xattr_list_mutex);
rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));

+ kfree(temp);
+
return rc;
}

--
2.17.0

2018-05-31 15:01:31

by Mimi Zohar

Subject: Re: [PATCH][next] EVM: fix memory leak of temporary buffer 'temp'

On Sun, 2018-05-27 at 23:15 +0100, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The allocation of 'temp' is not kfree'd and hence there is a memory
> leak on each call of evm_read_xattrs. Fix this by kfree'ing it
> after copying data from it back to the user space buffer 'buf'.
>
> Detected by CoverityScan, CID#1469386 ("Resource Leak")
>
> Fixes: fa516b66a1bf ("EVM: Allow runtime modification of the set of verified xattrs")
> Signed-off-by: Colin Ian King <[email protected]>

Thanks, this patch and "EVM: Fix null dereference on xattr when xattr
fails to allocate" are queued in the next-integrity branch.

Mimi

> ---
> security/integrity/evm/evm_secfs.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
> index a7a0a1acae99..fb8bc950aceb 100644
> --- a/security/integrity/evm/evm_secfs.c
> +++ b/security/integrity/evm/evm_secfs.c
> @@ -158,6 +158,8 @@ static ssize_t evm_read_xattrs(struct file *filp, char __user *buf,
> mutex_unlock(&xattr_list_mutex);
> rc = simple_read_from_buffer(buf, count, ppos, temp, strlen(temp));
>
> + kfree(temp);
> +
> return rc;
> }
>