Messages in this thread | | | From | Peter Gonda <> | Date | Mon, 16 May 2022 08:53:16 -0700 | Subject | Re: [PATCH v2] crypto: ccp - Use kzalloc for sev ioctl interfaces to prevent kernel memory leak |
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On Mon, May 16, 2022 at 8:46 AM John Allen <john.allen@amd.com> wrote: > > For some sev ioctl interfaces, input may be passed that is less than or > equal to SEV_FW_BLOB_MAX_SIZE, but larger than the data that PSP > firmware returns. In this case, kmalloc will allocate memory that is the > size of the input rather than the size of the data. Since PSP firmware > doesn't fully overwrite the buffer, the sev ioctl interfaces with the > issue may return uninitialized slab memory. > > Currently, all of the ioctl interfaces in the ccp driver are safe, but > to prevent future problems, change all ioctl interfaces that allocate > memory with kmalloc to use kzalloc. > > Fixes: e799035609e15 ("crypto: ccp: Implement SEV_PEK_CSR ioctl command") > Fixes: 76a2b524a4b1d ("crypto: ccp: Implement SEV_PDH_CERT_EXPORT ioctl command") > Fixes: d6112ea0cb344 ("crypto: ccp - introduce SEV_GET_ID2 command") > Cc: stable@vger.kernel.org > Reported-by: Andy Nguyen <theflow@google.com> > Suggested-by: David Rientjes <rientjes@google.com> > Suggested-by: Peter Gonda <pgonda@google.com> > Signed-off-by: John Allen <john.allen@amd.com> > --- > v2: > - Add fixes tags and CC stable@vger.kernel.org > ---
static int sev_ioctl_do_platform_status(struct sev_issue_cmd *argp) { struct sev_user_data_status data; int ret;
ret = __sev_do_cmd_locked(SEV_CMD_PLATFORM_STATUS, &data, &argp->error); if (ret) return ret;
if (copy_to_user((void __user *)argp->data, &data, sizeof(data))) ret = -EFAULT;
return ret; }
Would it be safer to memset @data here to all zeros too?
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