In the Linux kernel, the following vulnerability has been resolved:
rxrpc: rxrpc_verify_data ensure rx_dec_buffer alloc
rxrpc_recvmsg_data() calls rxrpc_verify_data() whenever the
rxrpc_call.rx_dec_buffer is unallocated and assumes that upon
successful return that rx_dec_buffer must be allocated.
However, rxrpc_verify_data() does not request an allocation if
the rxrpc_skb_priv.len is zero.
In addition, failure to allocate rx_dec_buffer will result in a
call to skb_copy_bits() with a NULL destination which can
trigger a NULL pointer dereference.
To prevent these issues rxrpc_verify_data() is modified to
always attempt to allocate the rxrpc_call.rx_dec_buffer if it
is NULL.
This issue was identified with assistance of a private
sashiko instance.
