On Wed, May 18, 2022 at 8:31 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 and memset the data buffer to zero in sev_ioctl_do_platform_status.
Fixes: 38103671aad3 ("crypto: ccp: Use the stack and common buffer for status commands") 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
Reviewed-by: Peter Gonda pgonda@google.com