3.16.79-rc1 review patch. If anyone has any objections, please let me know.
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From: Alan Stern stern@rowland.harvard.edu
commit 416dacb819f59180e4d86a5550052033ebb6d72c upstream.
The syzbot fuzzer has reported a pair of problems in the hidraw_ioctl() function: slab-out-of-bounds read and use-after-free read. An example of the first:
BUG: KASAN: slab-out-of-bounds in strlen+0x79/0x90 lib/string.c:525 Read of size 1 at addr ffff8881c8035f38 by task syz-executor.4/2833
CPU: 1 PID: 2833 Comm: syz-executor.4 Not tainted 5.3.0-rc2+ #1 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+0xca/0x13e lib/dump_stack.c:113 print_address_description+0x6a/0x32c mm/kasan/report.c:351 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482 kasan_report+0xe/0x12 mm/kasan/common.c:612 strlen+0x79/0x90 lib/string.c:525 strlen include/linux/string.h:281 [inline] hidraw_ioctl+0x245/0xae0 drivers/hid/hidraw.c:446 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd2d/0x1330 fs/ioctl.c:696 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7a68f6dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829 RDX: 0000000000000000 RSI: 0000000080404805 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7a68f6e6d4 R13: 00000000004c21de R14: 00000000004d5620 R15: 00000000ffffffff
The two problems have the same cause: hidraw_ioctl() fails to test whether the device has been removed. This patch adds the missing test.
Reported-and-tested-by: syzbot+5a6c4ec678a0c6ee84ba@syzkaller.appspotmail.com Signed-off-by: Alan Stern stern@rowland.harvard.edu Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/hid/hidraw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/hid/hidraw.c +++ b/drivers/hid/hidraw.c @@ -383,7 +383,7 @@ static long hidraw_ioctl(struct file *fi
mutex_lock(&minors_lock); dev = hidraw_table[minor]; - if (!dev) { + if (!dev || !dev->exist) { ret = -ENODEV; goto out; }