Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  net/rds: zero per-item info buffer before handing it to visitors  rds_for_each_conn_info() and rds_walk_conn_path_info() both hand a caller-allocated on-stack u64 buffer to a per-connection visitor and then copy the full item_len bytes back to user space via rds_info_copy() regardless of how much of the buffer the visitor actually wrote.  rds_ib_conn_info_visitor() and rds6_ib_conn_info_visitor() only write a subset of their output struct when the underlying rds_connection is not in state RDS_CONN_UP (src/dst addr, tos, sl and the two GIDs via explicit memsets). Several u32 fields (max_send_wr, max_recv_wr, max_send_sge, rdma_mr_max, rdma_mr_size, cache_allocs) and the 2-byte alignment hole between sl and cache_allocs remain as whatever stack contents preceded the visitor call and are then memcpy_to_user()'d out to user space.  struct rds_info_rdma_connection and struct rds6_info_rdma_connection are the only rds_info_* structs in include/uapi/linux/rds.h that are not marked __attribute__((packed)), so they have a real alignment hole. The other info visitors (rds_conn_info_visitor, rds6_conn_info_visitor, rds_tcp_tc_info, ...) write all fields of their packed output struct today and are not known to be vulnerable, but a future visitor that adds a conditional write-path would have the same bug.  Reproduction on a kernel built without CONFIG_INIT_STACK_ALL_ZERO=y: a local unprivileged user opens AF_RDS, sets SO_RDS_TRANSPORT=IB, binds to a local address on an RDMA-capable netdev (rxe soft-RoCE on any netdev is sufficient), sendto()'s any peer on the same subnet (fails cleanly but installs an rds_connection in the global hash in RDS_CONN_CONNECTING), then calls getsockopt(SOL_RDS, RDS_INFO_IB_CONNECTIONS). The returned 68-byte item contains 26 bytes of stack garbage including kernel text/data pointers:      0..7   0a 63 00 01 0a 63 00 02     src=10.99.0.1 dst=10.99.0.2     8..39  00 ...                      gids (memset-zeroed)     40..47 e0 92 a3 81 ff ff ff ff     kernel pointer (max_send_wr)     48..55 7f 37 b5 81 ff ff ff ff     kernel pointer (rdma_mr_max)     56..59 01 00 08 00                 rdma_mr_size (garbage)     60..61 00 00                       tos, sl     62..63 00 00                       alignment padding     64..67 18 00 00 00                 cache_allocs (garbage)  Fix by zeroing the per-item buffer in both rds_for_each_conn_info() and rds_walk_conn_path_info() before invoking the visitor. This covers the IPv4/IPv6 IB visitors and hardens all current and future visitors against the same class of bug.  No functional change for visitors that fully populate their output.  Changes in v2: - retarget at the net tree (subject prefix "[PATCH net v2]",   net/rds: prefix in the title) - pick up Reviewed-by tags from Sharath Srinivasan and   Allison Henderson

CVEs

• CVE-2026-52995