Eric Dumazet 38ba8b9241 can: j1939: fix kernel-infoleak in j1939_sk_sock2sockaddr_can() ... syzbot found that at least 2 bytes of kernel information were leaked during getsockname() on AF_CAN CAN_J1939 socket. Since struct sockaddr_can has in fact two holes, simply clear the whole area before filling it with useful data. BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253 CPU: 0 PID: 8466 Comm: syz-executor511 Not tainted 5.8.0-rc5-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+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253 instrument_copy_to_user include/linux/instrumented.h:91 [inline] _copy_to_user+0x18e/0x260 lib/usercopy.c:39 copy_to_user include/linux/uaccess.h:186 [inline] move_addr_to_user+0x3de/0x670 net/socket.c:237 __sys_getsockname+0x407/0x5e0 net/socket.c:1909 __do_sys_getsockname net/socket.c:1920 [inline] __se_sys_getsockname+0x91/0xb0 net/socket.c:1917 __x64_sys_getsockname+0x4a/0x70 net/socket.c:1917 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x440219 Code: Bad RIP value. RSP: 002b:00007ffe5ee150c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000033 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440219 RDX: 0000000020000240 RSI: 0000000020000100 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a20 R13: 0000000000401ab0 R14: 0000000000000000 R15: 0000000000000000 Local variable ----address@__sys_getsockname created at: __sys_getsockname+0x91/0x5e0 net/socket.c:1894 __sys_getsockname+0x91/0x5e0 net/socket.c:1894 Bytes 2-3 of 24 are uninitialized Memory access of size 24 starts at ffff8880ba2c7de8 Data copied to user address 0000000020000100 Fixes: 9d71dd0c70 ("can: add support of SAE J1939 protocol") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Cc: Robin van der Gracht <robin@protonic.nl> Cc: Oleksij Rempel <o.rempel@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: linux-can@vger.kernel.org Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Link: https://lore.kernel.org/r/20200813161834.4021638-1-edumazet@google.com Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>		2020-08-14 12:31:10 +02:00
..
j1939	can: j1939: fix kernel-infoleak in j1939_sk_sock2sockaddr_can()	2020-08-14 12:31:10 +02:00
af_can.c	net: can: kerneldoc fixes	2020-07-13 17:20:39 -07:00
af_can.h	can: introduce CAN midlayer private and allocate it automatically	2019-09-04 13:29:14 +02:00
bcm.c	net: make ->{get,set}sockopt in proto_ops optional	2020-07-19 18:16:41 -07:00
gw.c	can: gw: add support for CAN FD frames	2019-08-13 17:32:21 +02:00
Kconfig	treewide: replace '---help---' in Kconfig files with 'help'	2020-06-14 01:57:21 +09:00
Makefile	can: add support of SAE J1939 protocol	2019-09-04 14:22:33 +02:00
proc.c	can: introduce CAN midlayer private and allocate it automatically	2019-09-04 13:29:14 +02:00
raw.c	net: pass a sockptr_t into ->setsockopt	2020-07-24 15:41:54 -07:00