Re: [RFC PATCH for 4.21 06/16] cpu_opv: Provide cpu_opv system call (v8)
flat view
From: Sergey Senozhatsky <hidden>
Date: 2018-10-16 08:10:37
Also in:
lkml
Hi Mathieu, On (10/10/18 15:19), Mathieu Desnoyers wrote: [..]
quoted hunk ↗ jump to hunk
+SYSCALL_DEFINE4(cpu_opv, struct cpu_op __user *, ucpuopv, int, cpuopcnt, + int, cpu, int, flags) +{
[..]
quoted hunk ↗ jump to hunk
+again: + ret = cpu_opv_pin_pages(cpuopv, cpuopcnt, &vaddr_ptrs); + if (ret) + goto end; + ret = do_cpu_opv(cpuopv, cpuopcnt, &vaddr_ptrs, cpu); + if (ret == -EAGAIN) + retry = true; +end: + for (i = 0; i < vaddr_ptrs.nr_vaddr; i++) { + struct vaddr *vaddr = &vaddr_ptrs.addr[i]; + int j; + + vm_unmap_user_ram((void *)vaddr->mem, vaddr->nr_pages);
A dumb question. Both vm_unmap_user_ram() and vm_map_user_ram() can BUG_ON(). So this is userspace -> syscall -> cpu_opv() -> vm_unmap_user_ram() -> BUG_ON() Any chance someone can exploit it? -ss