RDMA/ucma: Check AF family prior resolving address

Garbage supplied by user will cause to UCMA module provide zero
memory size for memcpy(), because it wasn't checked, it will
produce unpredictable results in rdma_resolve_addr().

[   42.873814] BUG: KASAN: null-ptr-deref in rdma_resolve_addr+0xc8/0xfb0
[   42.874816] Write of size 28 at addr 00000000000000a0 by task resaddr/1044
[   42.876765]
[   42.876960] CPU: 1 PID: 1044 Comm: resaddr Not tainted 4.16.0-rc1-00057-gaa56a5293d7e hardkernel#34
[   42.877840] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014
[   42.879691] Call Trace:
[   42.880236]  dump_stack+0x5c/0x77
[   42.880664]  kasan_report+0x163/0x380
[   42.881354]  ? rdma_resolve_addr+0xc8/0xfb0
[   42.881864]  memcpy+0x34/0x50
[   42.882692]  rdma_resolve_addr+0xc8/0xfb0
[   42.883366]  ? deref_stack_reg+0x88/0xd0
[   42.883856]  ? vsnprintf+0x31a/0x770
[   42.884686]  ? rdma_bind_addr+0xc40/0xc40
[   42.885327]  ? num_to_str+0x130/0x130
[   42.885773]  ? deref_stack_reg+0x88/0xd0
[   42.886217]  ? __read_once_size_nocheck.constprop.6+0x10/0x10
[   42.887698]  ? unwind_get_return_address_ptr+0x50/0x50
[   42.888302]  ? replace_slot+0x147/0x170
[   42.889176]  ? delete_node+0x12c/0x340
[   42.890223]  ? __radix_tree_lookup+0xa9/0x160
[   42.891196]  ? ucma_resolve_ip+0xb7/0x110
[   42.891917]  ucma_resolve_ip+0xb7/0x110
[   42.893003]  ? ucma_resolve_addr+0x190/0x190
[   42.893531]  ? _copy_from_user+0x5e/0x90
[   42.894204]  ucma_write+0x174/0x1f0
[   42.895162]  ? ucma_resolve_route+0xf0/0xf0
[   42.896309]  ? dequeue_task_fair+0x67e/0xd90
[   42.897192]  ? put_prev_entity+0x7d/0x170
[   42.897870]  ? ring_buffer_record_is_on+0xd/0x20
[   42.898439]  ? tracing_record_taskinfo_skip+0x20/0x50
[   42.899686]  __vfs_write+0xc4/0x350
[   42.900142]  ? kernel_read+0xa0/0xa0
[   42.900602]  ? firmware_map_remove+0xdf/0xdf
[   42.901135]  ? do_task_dead+0x5d/0x60
[   42.901598]  ? do_exit+0xcc6/0x1220
[   42.902789]  ? __fget+0xa8/0xf0
[   42.903190]  vfs_write+0xf7/0x280
[   42.903600]  SyS_write+0xa1/0x120
[   42.904206]  ? SyS_read+0x120/0x120
[   42.905710]  ? compat_start_thread+0x60/0x60
[   42.906423]  ? SyS_read+0x120/0x120
[   42.908716]  do_syscall_64+0xeb/0x250
[   42.910760]  entry_SYSCALL_64_after_hwframe+0x21/0x86
[   42.912735] RIP: 0033:0x7f138b0afe99
[   42.914734] RSP: 002b:00007f138b799e98 EFLAGS: 00000287 ORIG_RAX: 0000000000000001
[   42.917134] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f138b0afe99
[   42.919487] RDX: 000000000000002e RSI: 0000000020000c40 RDI: 0000000000000004
[   42.922393] RBP: 00007f138b799ec0 R08: 00007f138b79a700 R09: 0000000000000000
[   42.925266] R10: 00007f138b79a700 R11: 0000000000000287 R12: 00007f138b799fc0
[   42.927570] R13: 0000000000000000 R14: 00007ffdbae757c0 R15: 00007f138b79a9c0
[   42.930047]
[   42.932681] Disabling lock debugging due to kernel taint
[   42.934795] BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
[   42.936939] IP: memcpy_erms+0x6/0x10
[   42.938864] PGD 80000001bea92067 P4D 80000001bea92067 PUD 1bea96067 PMD 0
[   42.941576] Oops: 0002 [hardkernel#1] SMP KASAN PTI
[   42.943952] CPU: 1 PID: 1044 Comm: resaddr Tainted: G    B 4.16.0-rc1-00057-gaa56a5293d7e hardkernel#34
[   42.946964] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-0-g63451fca13-prebuilt.qemu-project.org 04/01/2014
[   42.952336] RIP: 0010:memcpy_erms+0x6/0x10
[   42.954707] RSP: 0018:ffff8801c8b479c8 EFLAGS: 00010286
[   42.957227] RAX: 00000000000000a0 RBX: ffff8801c8b47ba0 RCX: 000000000000001c
[   42.960543] RDX: 000000000000001c RSI: ffff8801c8b47bbc RDI: 00000000000000a0
[   42.963867] RBP: ffff8801c8b47b60 R08: 0000000000000000 R09: ffffed0039168ed1
[   42.967303] R10: 0000000000000001 R11: ffffed0039168ed0 R12: ffff8801c8b47bbc
[   42.970685] R13: 00000000000000a0 R14: 1ffff10039168f4a R15: 0000000000000000
[   42.973631] FS:  00007f138b79a700(0000) GS:ffff8801e5d00000(0000) knlGS:0000000000000000
[   42.976831] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   42.979239] CR2: 00000000000000a0 CR3: 00000001be908002 CR4: 00000000003606a0
[   42.982060] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   42.984877] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   42.988033] Call Trace:
[   42.990487]  rdma_resolve_addr+0xc8/0xfb0
[   42.993202]  ? deref_stack_reg+0x88/0xd0
[   42.996055]  ? vsnprintf+0x31a/0x770
[   42.998707]  ? rdma_bind_addr+0xc40/0xc40
[   43.000985]  ? num_to_str+0x130/0x130
[   43.003410]  ? deref_stack_reg+0x88/0xd0
[   43.006302]  ? __read_once_size_nocheck.constprop.6+0x10/0x10
[   43.008780]  ? unwind_get_return_address_ptr+0x50/0x50
[   43.011178]  ? replace_slot+0x147/0x170
[   43.013517]  ? delete_node+0x12c/0x340
[   43.016019]  ? __radix_tree_lookup+0xa9/0x160
[   43.018755]  ? ucma_resolve_ip+0xb7/0x110
[   43.021270]  ucma_resolve_ip+0xb7/0x110
[   43.023968]  ? ucma_resolve_addr+0x190/0x190
[   43.026312]  ? _copy_from_user+0x5e/0x90
[   43.029384]  ucma_write+0x174/0x1f0
[   43.031861]  ? ucma_resolve_route+0xf0/0xf0
[   43.034782]  ? dequeue_task_fair+0x67e/0xd90
[   43.037483]  ? put_prev_entity+0x7d/0x170
[   43.040215]  ? ring_buffer_record_is_on+0xd/0x20
[   43.042990]  ? tracing_record_taskinfo_skip+0x20/0x50
[   43.045595]  __vfs_write+0xc4/0x350
[   43.048624]  ? kernel_read+0xa0/0xa0
[   43.051604]  ? firmware_map_remove+0xdf/0xdf
[   43.055379]  ? do_task_dead+0x5d/0x60
[   43.058000]  ? do_exit+0xcc6/0x1220
[   43.060783]  ? __fget+0xa8/0xf0
[   43.063133]  vfs_write+0xf7/0x280
[   43.065677]  SyS_write+0xa1/0x120
[   43.068647]  ? SyS_read+0x120/0x120
[   43.071179]  ? compat_start_thread+0x60/0x60
[   43.074025]  ? SyS_read+0x120/0x120
[   43.076705]  do_syscall_64+0xeb/0x250
[   43.079006]  entry_SYSCALL_64_after_hwframe+0x21/0x86
[   43.081606] RIP: 0033:0x7f138b0afe99
[   43.083679] RSP: 002b:00007f138b799e98 EFLAGS: 00000287 ORIG_RAX: 0000000000000001
[   43.086802] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f138b0afe99
[   43.089989] RDX: 000000000000002e RSI: 0000000020000c40 RDI: 0000000000000004
[   43.092866] RBP: 00007f138b799ec0 R08: 00007f138b79a700 R09: 0000000000000000
[   43.096233] R10: 00007f138b79a700 R11: 0000000000000287 R12: 00007f138b799fc0
[   43.098913] R13: 0000000000000000 R14: 00007ffdbae757c0 R15: 00007f138b79a9c0
[   43.101809] Code: 90 90 90 90 90 eb 1e 0f 1f 00 48 89 f8 48 89 d1 48
c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48
89 d1 <f3> a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38
[   43.107950] RIP: memcpy_erms+0x6/0x10 RSP: ffff8801c8b479c8

Reported-by: <syzbot+1d8c43206853b369d00c@syzkaller.appspotmail.com>
Fixes: 7521663 ("RDMA/cma: Export rdma cm interface to userspace")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/ucma.c

@@ -664,19 +664,23 @@ static ssize_t ucma_resolve_ip(struct ucma_file *file,
 			       int in_len, int out_len)
 {
 	struct rdma_ucm_resolve_ip cmd;
+	struct sockaddr *src, *dst;
 	struct ucma_context *ctx;
 	int ret;
 
 	if (copy_from_user(&cmd, inbuf, sizeof(cmd)))
 		return -EFAULT;
 
+	src = (struct sockaddr *) &cmd.src_addr;
+	dst = (struct sockaddr *) &cmd.dst_addr;
+	if (!rdma_addr_size(src) || !rdma_addr_size(dst))
+		return -EINVAL;
+
 	ctx = ucma_get_ctx(file, cmd.id);
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
 
-	ret = rdma_resolve_addr(ctx->cm_id, (struct sockaddr *) &cmd.src_addr,
-				(struct sockaddr *) &cmd.dst_addr,
-				cmd.timeout_ms);
+	ret = rdma_resolve_addr(ctx->cm_id, src, dst, cmd.timeout_ms);
 	ucma_put_ctx(ctx);
 	return ret;
 }