In the Linux kernel, the following vulnerability has been resolved:

crypto: ixp4xx - fix buffer chain unwind on allocation failure

chainup buffers() builds a linked list of buffer descriptors for a scatterlist. If dma pool alloc() fails while constructing the list, the current code sets buf to NULL and later dereferences it unconditionally at the end of the function:

buf->next = NULL; buf->phys next = 0;

This can lead to a null-pointer dereference on allocation failure.

If the failure happens after part of the descriptor chain has already been allocated and DMA-mapped, the partially constructed chain also needs to be released.

Fix this by terminating the partially constructed chain on allocation failure and letting the callers unwind it via their existing cleanup paths. Also fix ablk perform() to preserve the hook pointers before checking for failure, so partially built chains can be freed correctly.