fb317eb23b
KMSAN reported the following kernel-infoleak issue: ===================================================== BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:29 [inline] iterate_and_advance2 include/linux/iov_iter.h:245 [inline] iterate_and_advance include/linux/iov_iter.h:271 [inline] _copy_to_iter+0x4ec/0x2bc0 lib/iov_iter.c:186 copy_to_iter include/linux/uio.h:197 [inline] simple_copy_to_iter net/core/datagram.c:532 [inline] __skb_datagram_iter.5+0x148/0xe30 net/core/datagram.c:420 skb_copy_datagram_iter+0x52/0x210 net/core/datagram.c:546 skb_copy_datagram_msg include/linux/skbuff.h:3960 [inline] netlink_recvmsg+0x43d/0x1630 net/netlink/af_netlink.c:1967 sock_recvmsg_nosec net/socket.c:1044 [inline] sock_recvmsg net/socket.c:1066 [inline] __sys_recvfrom+0x476/0x860 net/socket.c:2246 __do_sys_recvfrom net/socket.c:2264 [inline] __se_sys_recvfrom net/socket.c:2260 [inline] __x64_sys_recvfrom+0x130/0x200 net/socket.c:2260 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit was created at: slab_post_alloc_hook+0x103/0x9e0 mm/slab.h:768 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x5f7/0xb50 mm/slub.c:3523 kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:560 __alloc_skb+0x2fd/0x770 net/core/skbuff.c:651 alloc_skb include/linux/skbuff.h:1286 [inline] tipc_tlv_alloc net/tipc/netlink_compat.c:156 [inline] tipc_get_err_tlv+0x90/0x5d0 net/tipc/netlink_compat.c:170 tipc_nl_compat_recv+0x1042/0x15d0 net/tipc/netlink_compat.c:1324 genl_family_rcv_msg_doit net/netlink/genetlink.c:972 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1052 [inline] genl_rcv_msg+0x1220/0x12c0 net/netlink/genetlink.c:1067 netlink_rcv_skb+0x4a4/0x6a0 net/netlink/af_netlink.c:2545 genl_rcv+0x41/0x60 net/netlink/genetlink.c:1076 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0xf4b/0x1230 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x1242/0x1420 net/netlink/af_netlink.c:1910 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x997/0xd60 net/socket.c:2588 ___sys_sendmsg+0x271/0x3b0 net/socket.c:2642 __sys_sendmsg net/socket.c:2671 [inline] __do_sys_sendmsg net/socket.c:2680 [inline] __se_sys_sendmsg net/socket.c:2678 [inline] __x64_sys_sendmsg+0x2fa/0x4a0 net/socket.c:2678 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x63/0x6b Bytes 34-35 of 36 are uninitialized Memory access of size 36 starts at ffff88802d464a00 Data copied to user address 00007ff55033c0a0 CPU: 0 PID: 30322 Comm: syz-executor.0 Not tainted 6.6.0-14500-g1c41041124bd #10 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014 ===================================================== tipc_add_tlv() puts TLV descriptor and value onto `skb`. This size is calculated with TLV_SPACE() macro. It adds the size of struct tlv_desc and the length of TLV value passed as an argument, and aligns the result to a multiple of TLV_ALIGNTO, i.e., a multiple of 4 bytes. If the size of struct tlv_desc plus the length of TLV value is not aligned, the current implementation leaves the remaining bytes uninitialized. This is the cause of the above kernel-infoleak issue. This patch resolves this issue by clearing data up to an aligned size. Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat") Signed-off-by: Shigeru Yoshida <syoshida@redhat.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.