On Mon, Mar 09, 2020 at 04:16:48PM -0300, Jason Gunthorpe wrote:
> Empty device names cannot be added to sysfs and crash with:
>
> kobject: (00000000f9de3792): attempted to be registered with empty name!
> WARNING: CPU: 1 PID: 10856 at lib/kobject.c:234 kobject_add_internal+0x7ac/0x9a0 lib/kobject.c:234
> Kernel panic - not syncing: panic_on_warn set ...
> CPU: 1 PID: 10856 Comm: syz-executor459 Not tainted 5.6.0-rc3-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> __dump_stack lib/dump_stack.c:77 [inline]
> dump_stack+0x197/0x210 lib/dump_stack.c:118
> panic+0x2e3/0x75c kernel/panic.c:221
> __warn.cold+0x2f/0x3e kernel/panic.c:582
> report_bug+0x289/0x300 lib/bug.c:195
> fixup_bug arch/x86/kernel/traps.c:174 [inline]
> fixup_bug arch/x86/kernel/traps.c:169 [inline]
> do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
> do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
> invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
> RIP: 0010:kobject_add_internal+0x7ac/0x9a0 lib/kobject.c:234
> Code: 7a ca ca f9 e9 f0 f8 ff ff 4c 89 f7 e8 cd ca ca f9 e9 95 f9 ff ff e8 13 25 8c f9 4c 89 e6 48 c7 c7 a0 08 1a 89 e8 a3 76 5c f9 <0f> 0b 41 bd ea ff ff ff e9 52 ff ff ff e8 f2 24 8c f9 0f 0b e8 eb
> RSP: 0018:ffffc90002006eb0 EFLAGS: 00010286
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffffffff815eae46 RDI: fffff52000400dc8
> RBP: ffffc90002006f08 R08: ffff8880972ac500 R09: ffffed1015d26659
> R10: ffffed1015d26658 R11: ffff8880ae9332c7 R12: ffff888093034668
> R13: 0000000000000000 R14: ffff8880a69d7600 R15: 0000000000000001
> kobject_add_varg lib/kobject.c:390 [inline]
> kobject_add+0x150/0x1c0 lib/kobject.c:442
> device_add+0x3be/0x1d00 drivers/base/core.c:2412
> ib_register_device drivers/infiniband/core/device.c:1371 [inline]
> ib_register_device+0x93e/0xe40 drivers/infiniband/core/device.c:1343
> rxe_register_device+0x52e/0x655 drivers/infiniband/sw/rxe/rxe_verbs.c:1231
> rxe_add+0x122b/0x1661 drivers/infiniband/sw/rxe/rxe.c:302
> rxe_net_add+0x91/0xf0 drivers/infiniband/sw/rxe/rxe_net.c:539
> rxe_newlink+0x39/0x90 drivers/infiniband/sw/rxe/rxe.c:318
> nldev_newlink+0x28a/0x430 drivers/infiniband/core/nldev.c:1538
> rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
> rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
> rdma_nl_rcv+0x5d9/0x980 drivers/infiniband/core/netlink.c:259
> netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
> netlink_unicast+0x59e/0x7e0 net/netlink/af_netlink.c:1329
> netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1918
> sock_sendmsg_nosec net/socket.c:652 [inline]
> sock_sendmsg+0xd7/0x130 net/socket.c:672
> ____sys_sendmsg+0x753/0x880 net/socket.c:2343
> ___sys_sendmsg+0x100/0x170 net/socket.c:2397
> __sys_sendmsg+0x105/0x1d0 net/socket.c:2430
> __do_sys_sendmsg net/socket.c:2439 [inline]
> __se_sys_sendmsg net/socket.c:2437 [inline]
> __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2437
> do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> Prevent empty names when checking the name provided from userspace during
> newlink and rename.
>
> Cc: stable@xxxxxxxxxx
> Fixes: 3856ec4b93c9 ("RDMA/core: Add RDMA_NLDEV_CMD_NEWLINK/DELLINK support")
> Fixes: 05d940d3a3ec ("RDMA/nldev: Allow IB device rename through RDMA netlink")
> Reported-by: syzbot+da615ac67d4dbea32cbc@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
> drivers/infiniband/core/nldev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next
>
> diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
> index 37b433aa730610..7147a4e49167db 100644
> +++ b/drivers/infiniband/core/nldev.c
> @@ -1514,7 +1514,7 @@ static int nldev_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
>
> nla_strlcpy(ibdev_name, tb[RDMA_NLDEV_ATTR_DEV_NAME],
> sizeof(ibdev_name));
> - if (strchr(ibdev_name, '%'))
> + if (strchr(ibdev_name, '%') || strlen(ibdev_name) == 0)
> return -EINVAL;
>
> nla_strlcpy(type, tb[RDMA_NLDEV_ATTR_LINK_TYPE], sizeof(type));
Gah, a hunk got lost here:
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -918,6 +918,10 @@ static int nldev_set_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
nla_strlcpy(name, tb[RDMA_NLDEV_ATTR_DEV_NAME],
IB_DEVICE_NAME_MAX);
+ if (strlen(name) == 0) {
+ err = -EINVAL;
+ goto done;
+ }
err = ib_device_rename(device, name);
goto done;
}
Jason
