In the Linux kernel, the following vulnerability has been resolved:
RDMA/ionic: Fix kernel stack leak in ionic_create_cq()
struct ionic_cq_resp resp {
__u32 cqid[2]; // offset 0 - PARTIALLY SET (see below)
__u8 udma_mask; // offset 8 - SET (resp.udma_mask = vcq->udma_mask)
__u8 rsvd[7]; // offset 9 - NEVER SET <- LEAK
};
rsvd[7]: 7 bytes of stack memory leaked unconditionally.
cqid[2]: The loop at line 1256 iterates over udma_idx but skips indices
where !(vcq->udma_mask & BIT(udma_idx)). The array has 2 entries but
udma_count could be 1, meaning cqid[1] might never be written via
ionic_create_cq_common(). If udma_mask only has bit 0 set, cqid[1] (4
bytes) is also leaked. So potentially 11 bytes leaked.