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b=JglQ2D7xWlF+jVeRZBQCYSfWeujkI2+Z/N52xLrrRIYJRtiaXcmZMSI85Z2z+Spfq yxzgLQgRU7QNGUw1WUuhVYR6C5azLNuDjlM8u9h8Qjgz+Hn8EHh1zuTUJ4MrGr+P/r lCWZgGxJ6eOzoWDXOSk0p3T2OBrOzjkZqhA8DwkM= Received: from pek-lxu-l1.wrs.com ([36.129.58.158]) by newxmesmtplogicsvrszc5-0.qq.com (NewEsmtp) with SMTP id 7AF038ED; Fri, 16 Feb 2024 15:30:47 +0800 X-QQ-mid: xmsmtpt1708068647tzqympn6w Message-ID: X-QQ-XMAILINFO: NhpLzBn2I3XwYSLVf/8Xh+7+MIRs05BE/7Vh5PSJieJn3W2fTye9GkDn6FJ70g xXdV/4O6/JYaFIHCw6UHV38RuHI6rhuZrjL7IrUuX+hakjaXZYY94m+sgAU7CGy+x2MOaZZONIaC iF2+NjBGCJ3/5GzpORsuxFio8wpZNqVi/0dxECcIZXwx91R+RUv26/quIc8i4es2kVO17wdWwBor J2uXIsmhmHnP6fmx8GOUn7ejfFbYq2D0f2kxw1+U9AySXwP4g6jQqAvmldae34dmYO/mHFWfPjeb WxmUkNfxFPrah53xVNXuLZFp7eyQNLjjpq/uPuyXCiJON6RSwRSZuJDDz1eFWn0MN66RPyETjhxT 5JJXIqdHXza3DnHQTgkuKywCBnWkaRfAE4hdZc7N7Vh109XsKXODV1XzWL2UedzjzrMbs4cWEYVt K/H0qpc31pDDXUC/5ptxnmjYQMwxPg2yxwp75t7IysYYrSdvn28UTeEH41NITDWSYkCuSHkLZo0s K0LTIKYRmZtoDIxydWPLZwIHb9d1Nw1qtxRwyU3SE/026t5DtjKOl3WkpcaHJsC7t0dbwnRjkviT NXF+s60ZYCt4wHVXUcEMfe1yGfHt5pn4wcjKTyyaL0mHOMmfABqoZyM3T6brzpgcAsBV90CXO6eM 6s4c1Yl/k/yx0A+v8qTkQmwB8NNa5931sYTkHyMQ+ZqYGILq3GBbg6ARu18BCnfvWnnOeRi8mPjN Ns8BoPHHBC90b5rq+DFEQbHFfUWWbyWEqfnQt4P6NxppxdnozrMhnqcbSYZ77G7lAwEszTfuSpXB UmwmaIljwPOVlz5izt9B+cmf6Y+F1TF+krGYOKhJ0ku1JW/GCOk+ULtadcCVfiHSiLIEApVxIYXp IiB7XnEprRNUuffUXA74Wnhlsgt9PwW/xO/6XtffWJ4Zmf4USrKpRCu8OSANW4qA== X-QQ-XMRINFO: OWPUhxQsoeAVDbp3OJHYyFg= From: Edward Adam Davis To: syzbot+ce750e124675d4599449@syzkaller.appspotmail.com Cc: isely@pobox.com, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-usb@vger.kernel.org, mchehab@kernel.org, pvrusb2-owner@isely.net, pvrusb2@isely.net, syzkaller-bugs@googlegroups.com Subject: [PATCH usb] media/pvrusb2: fix uaf in pvr2_context_set_notify Date: Fri, 16 Feb 2024 15:30:47 +0800 X-OQ-MSGID: <20240216073046.1137237-2-eadavis@qq.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <00000000000028b68806103b4266@google.com> References: <00000000000028b68806103b4266@google.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 [Syzbot reported] BUG: KASAN: slab-use-after-free in pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35 Read of size 4 at addr ffff888113aeb0d8 by task kworker/1:1/26 CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.8.0-rc1-syzkaller-00046-gf1a27f081c1f #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Workqueue: usb_hub_wq hub_event Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc4/0x620 mm/kasan/report.c:488 kasan_report+0xda/0x110 mm/kasan/report.c:601 pvr2_context_set_notify+0x2c4/0x310 drivers/media/usb/pvrusb2/pvrusb2-context.c:35 pvr2_context_notify drivers/media/usb/pvrusb2/pvrusb2-context.c:95 [inline] pvr2_context_disconnect+0x94/0xb0 drivers/media/usb/pvrusb2/pvrusb2-context.c:272 Freed by task 906: kasan_save_stack+0x33/0x50 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:640 poison_slab_object mm/kasan/common.c:241 [inline] __kasan_slab_free+0x106/0x1b0 mm/kasan/common.c:257 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2121 [inline] slab_free mm/slub.c:4299 [inline] kfree+0x105/0x340 mm/slub.c:4409 pvr2_context_check drivers/media/usb/pvrusb2/pvrusb2-context.c:137 [inline] pvr2_context_thread_func+0x69d/0x960 drivers/media/usb/pvrusb2/pvrusb2-context.c:158 [Analyze] Task A set disconnect_flag = !0, which resulted in Task B's condition being met and releasing mp, leading to this issue. [Fix] Place the disconnect_flag assignment operation after all code in pvr2_context_disconnect() to avoid this issue. Reported-and-tested-by: syzbot+ce750e124675d4599449@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis --- drivers/media/usb/pvrusb2/pvrusb2-context.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/usb/pvrusb2/pvrusb2-context.c b/drivers/media/usb/pvrusb2/pvrusb2-context.c index 1764674de98b..e93bca93ce4c 100644 --- a/drivers/media/usb/pvrusb2/pvrusb2-context.c +++ b/drivers/media/usb/pvrusb2/pvrusb2-context.c @@ -267,9 +267,9 @@ static void pvr2_context_exit(struct pvr2_context *mp) void pvr2_context_disconnect(struct pvr2_context *mp) { pvr2_hdw_disconnect(mp->hdw); - mp->disconnect_flag = !0; if (!pvr2_context_shutok()) pvr2_context_notify(mp); + mp->disconnect_flag = !0; }