From: Michael Bommarito <michael.bommarito@gmail.com> mainline inclusion from mainline-v7.1-rc3 commit 4c6f86d85d03cdb33addce86aa69aa795ca6c47a category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15307 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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. Cc: stable@vger.kernel.org Fixes: 8700e3e7c485 ("Soft RoCE driver") Link: https://patch.msgid.link/r/20260414111555.3386793-1-michael.bommarito@gmail.... Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Liu Kai <liukai284@huawei.com> --- drivers/infiniband/sw/rxe/rxe_recv.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/infiniband/sw/rxe/rxe_recv.c b/drivers/infiniband/sw/rxe/rxe_recv.c index 71a56c4b721a..592e351ccec5 100644 --- a/drivers/infiniband/sw/rxe/rxe_recv.c +++ b/drivers/infiniband/sw/rxe/rxe_recv.c @@ -364,6 +364,17 @@ void rxe_rcv(struct sk_buff *skb) pkt->qp = NULL; pkt->mask |= rxe_opcode[pkt->opcode].mask; + /* + * Unknown opcodes have a zero-initialized rxe_opcode[] entry, so + * both mask and length are 0. Reject them before any length math: + * rxe_icrc_hdr() would otherwise compute length - RXE_BTH_BYTES + * and pass the underflowed value to rxe_crc32(), producing an + * out-of-bounds read. + */ + if (unlikely(!rxe_opcode[pkt->opcode].mask || + !rxe_opcode[pkt->opcode].length)) + goto drop; + if (unlikely(pkt->paylen < header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE)) goto drop; -- 2.34.1