The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 0c81ffc60d5280991773d17e84bda605387148b1 Mon Sep 17 00:00:00 2001
From: Leon Romanovsky leonro@mellanox.com Date: Tue, 13 Mar 2018 18:37:27 +0200 Subject: [PATCH] RDMA/ucma: Don't allow join attempts for unsupported AF family
Users can provide garbage while calling to ucma_join_ip_multicast(), it will indirectly cause to rdma_addr_size() return 0, making the call to ucma_process_join(), which had the right checks, but it is better to check the input as early as possible.
The following crash from syzkaller revealed it.
kernel BUG at lib/string.c:1052! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 0 PID: 4113 Comm: syz-executor0 Not tainted 4.16.0-rc5+ #261 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:fortify_panic+0x13/0x20 lib/string.c:1051 RSP: 0018:ffff8801ca81f8f0 EFLAGS: 00010286 RAX: 0000000000000022 RBX: 1ffff10039503f23 RCX: 0000000000000000 RDX: 0000000000000022 RSI: 1ffff10039503ed3 RDI: ffffed0039503f12 RBP: ffff8801ca81f8f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000006 R11: 0000000000000000 R12: ffff8801ca81f998 R13: ffff8801ca81f938 R14: ffff8801ca81fa58 R15: 000000000000fa00 FS: 0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:000000000a12a900 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000008138024 CR3: 00000001cbb58004 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: memcpy include/linux/string.h:344 [inline] ucma_join_ip_multicast+0x36b/0x3b0 drivers/infiniband/core/ucma.c:1421 ucma_write+0x2d6/0x3d0 drivers/infiniband/core/ucma.c:1633 __vfs_write+0xef/0x970 fs/read_write.c:480 vfs_write+0x189/0x510 fs/read_write.c:544 SYSC_write fs/read_write.c:589 [inline] SyS_write+0xef/0x220 fs/read_write.c:581 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f9ec99 RSP: 002b:00000000ff8172cc EFLAGS: 00000282 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000100 RDX: 0000000000000063 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Code: 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 0b 48 89 df e8 42 2c e3 fb eb de 55 48 89 fe 48 c7 c7 80 75 98 86 48 89 e5 e8 85 95 94 fb <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56 RIP: fortify_panic+0x13/0x20 lib/string.c:1051 RSP: ffff8801ca81f8f0
Fixes: 5bc2b7b397b0 ("RDMA/ucma: Allow user space to specify AF_IB when joining multicast") Reported-by: syzbot+2287ac532caa81900a4e@syzkaller.appspotmail.com Signed-off-by: Leon Romanovsky leonro@mellanox.com Reviewed-by: Sean Hefty sean.hefty@intel.com Signed-off-by: Doug Ledford dledford@redhat.com
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c index 3a9d0f5b5881..699a46d4c0c5 100644 --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -1349,7 +1349,7 @@ static ssize_t ucma_process_join(struct ucma_file *file, return -ENOSPC;
addr = (struct sockaddr *) &cmd->addr; - if (!cmd->addr_size || (cmd->addr_size != rdma_addr_size(addr))) + if (cmd->addr_size != rdma_addr_size(addr)) return -EINVAL;
if (cmd->join_flags == RDMA_MC_JOIN_FLAG_FULLMEMBER) @@ -1417,6 +1417,9 @@ static ssize_t ucma_join_ip_multicast(struct ucma_file *file, join_cmd.uid = cmd.uid; join_cmd.id = cmd.id; join_cmd.addr_size = rdma_addr_size((struct sockaddr *) &cmd.addr); + if (!join_cmd.addr_size) + return -EINVAL; + join_cmd.join_flags = RDMA_MC_JOIN_FLAG_FULLMEMBER; memcpy(&join_cmd.addr, &cmd.addr, join_cmd.addr_size);
@@ -1432,6 +1435,9 @@ static ssize_t ucma_join_multicast(struct ucma_file *file, if (copy_from_user(&cmd, inbuf, sizeof(cmd))) return -EFAULT;
+ if (!rdma_addr_size((struct sockaddr *)&cmd.addr)) + return -EINVAL; + return ucma_process_join(file, &cmd, out_len); }