Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  RDMA/rxe: Reject unknown opcodes before ICRC processing  Even after applying commit 7244491dab34 ("RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv"), a single unauthenticated UDP packet can still trigger panic.  That patch handled payload_size() underflow only for valid opcodes with short packets, not for packets carrying an unknown opcode.  The unknown-opcode OOB read described below predates that commit and reaches back to the initial Soft RoCE driver.  The check added there reads      pkt->paylen < header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE  where header_size(pkt) expands to rxe_opcode[pkt->opcode].length.  The rxe_opcode[] array has 256 entries but is only populated for defined IB opcodes; any other entry (for example opcode 0xff) is zero-initialized, so length == 0 and the check degenerates to      pkt->paylen < 0 + bth_pad(pkt) + RXE_ICRC_SIZE  which does not constrain pkt->paylen enough.  rxe_icrc_hdr() then computes      rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES  which underflows when length == 0 and passes a huge value to rxe_crc32(), causing an out-of-bounds read of the skb payload.  Reproduced on v7.0-rc7 with that fix applied, QEMU/KVM with CONFIG_RDMA_RXE=y and CONFIG_KASAN=y, after      rdma link add rxe0 type rxe netdev eth0  A single 48-byte UDP packet to port 4791 with BTH opcode=0xff and QPN=IB_MULTICAST_QPN triggers:      BUG: KASAN: slab-out-of-bounds in crc32_le+0x115/0x170     Read of size 1 at addr ...     The buggy address is located 0 bytes to the right of      allocated 704-byte region     Call Trace:      crc32_le+0x115/0x170      rxe_icrc_hdr.isra.0+0x226/0x300      rxe_icrc_check+0x13f/0x3a0      rxe_rcv+0x6e1/0x16e0      rxe_udp_encap_recv+0x20a/0x320      udp_queue_rcv_one_skb+0x7ed/0x12c0  Subsequent packets with the same shape fault on unmapped memory and panic the kernel.  The trigger requires only module load and "rdma link add"; no QP, no connection, and no authentication.  Fix this by rejecting packets whose opcode has no rxe_opcode[] entry, detected via the zero mask or zero length, before any length arithmetic runs.