On 6/29/2023 7:14 PM, Paul Moore wrote:
> On Jun 29, 2023 Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
>> Implement Smack support for security_[gs]etselfattr.
>> Refactor the setprocattr hook to avoid code duplication.
>>
>> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
>> ---
>> security/smack/smack_lsm.c | 106 +++++++++++++++++++++++++++++++++++--
>> 1 file changed, 101 insertions(+), 5 deletions(-)
>>
>> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
>> index cf847cfe5ed8..4a84639e9db9 100644
>> --- a/security/smack/smack_lsm.c
>> +++ b/security/smack/smack_lsm.c
> ..
>
>> @@ -3629,6 +3668,61 @@ static int smack_setprocattr(const char *name, void *value, size_t size)
>> return size;
>> }
>>
>> +/**
>> + * smack_setselfattr - Set a Smack process attribute
>> + * @attr: which attribute to set
>> + * @ctx: buffer containing the data
>> + * @size: size of @ctx
>> + * @flags: unused
>> + *
>> + * Fill the passed user space @ctx with the details of the requested
>> + * attribute.
>> + *
>> + * Returns 0 on success, an error code otherwise.
>> + */
>> +static int smack_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
>> + size_t size, u32 flags)
>> +{
>> + struct lsm_ctx *lctx;
>> + int rc;
>> +
>> + lctx = kmalloc(size, GFP_KERNEL);
>> + if (lctx == NULL)
>> + return -ENOMEM;
>> +
>> + if (copy_from_user(lctx, ctx, size))
>> + rc = -EFAULT;
>> + else if (lctx->ctx_len > size)
>> + rc = -E2BIG;
>> + else
>> + rc = do_setattr(attr, lctx->ctx, lctx->ctx_len);
>> +
>> + kfree(lctx);
>> + if (rc > 0)
>> + return 0;
>> + return rc;
>> +}
>> +
>> +/**
>> + * smack_setprocattr - Smack process attribute setting
>> + * @name: the name of the attribute in /proc/.../attr
>> + * @value: the value to set
>> + * @size: the size of the value
>> + *
>> + * Sets the Smack value of the task. Only setting self
>> + * is permitted and only with privilege
>> + *
>> + * Returns the length of the smack label or an error code
>> + */
>> +static int smack_setprocattr(const char *name, void *value, size_t size)
>> +{
>> + int attr = lsm_name_to_attr(name);
>> +
>> + if (attr == LSM_ATTR_UNDEF)
> That should be '(attr != LSM_ATTR_UNDEF)', right?
Yes, you're right. I'll fix and respin.
>
>> + return do_setattr(attr, value, size);
>> + return -EINVAL;
>> +}
>> +
>> /**
>> * smack_unix_stream_connect - Smack access on UDS
>> * @sock: one sock
>> @@ -4939,6 +5033,8 @@ static struct security_hook_list smack_hooks[] __ro_after_init = {
>>
>> LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),
>>
>> + LSM_HOOK_INIT(getselfattr, smack_getselfattr),
>> + LSM_HOOK_INIT(setselfattr, smack_setselfattr),
>> LSM_HOOK_INIT(getprocattr, smack_getprocattr),
>> LSM_HOOK_INIT(setprocattr, smack_setprocattr),
>>
>> --
>> 2.40.1
> --
> paul-moore.com
