cbcvebase.
CVE-2022-49767
published 2025-05-01

CVE-2022-49767: In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: always use O_NONBLOCK read/write syzbot is reporting hung task at…

PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.19%
8.8th percentile
In the Linux kernel, the following vulnerability has been resolved: 9p/trans_fd: always use O_NONBLOCK read/write syzbot is reporting hung task at p9_fd_close() [1], for p9_mux_poll_stop() from p9_conn_destroy() from p9_fd_close() is failing to interrupt already started kernel_read() from p9_fd_read() from p9_read_work() and/or kernel_write() from p9_fd_write() from p9_write_work() requests. Since p9_socket_open() sets O_NONBLOCK flag, p9_mux_poll_stop() does not need to interrupt kernel_read()/kernel_write(). However, since p9_fd_open() does not set O_NONBLOCK flag, but pipe blocks unless signal is pending, p9_mux_poll_stop() needs to interrupt kernel_read()/kernel_write() when the file descriptor refers to a pipe. In other words, pipe file descriptor needs to be handled as if socket file descriptor. We somehow need to interrupt kernel_read()/kernel_write() on pipes. A minimal change, which this patch is doing, is to set O_NONBLOCK flag from p9_fd_open(), for O_NONBLOCK flag does not affect reading/writing of regular files. But this approach changes O_NONBLOCK flag on userspace- supplied file descriptors (which might break userspace programs), and O_NONBLOCK flag could be changed by userspace. It would be possible to set O_NONBLOCK flag every time p9_fd_read()/p9_fd_write() is invoked, but still remains small race window for clearing O_NONBLOCK flag. If we don't want to manipulate O_NONBLOCK flag, we might be able to surround kernel_read()/kernel_write() with set_thread_flag(TIF_SIGPENDING) and recalc_sigpending(). Since p9_read_work()/p9_write_work() works are processed by kernel threads which process global system_wq workqueue, signals could not be delivered from remote threads when p9_mux_poll_stop() from p9_conn_destroy() from p9_fd_close() is called. Therefore, calling set_thread_flag(TIF_SIGPENDING)/recalc_sigpending() every time would be needed if we count on signals for making kernel_read()/kernel_write() non-blocking. [Dominique: add comment at Chri

Affected

21 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.0.10-1 (bookworm)linux 6.0.10-1 (bookworm)
linuxlinux——
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < 0b5e6bd72b8171364616841603a70e4ba98370630b5e6bd72b8171364616841603a70e4ba9837063
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < 9f8554615df668e4bf83294633ee9d232b28ce459f8554615df668e4bf83294633ee9d232b28ce45
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < 7abf40f06a76c0dff42eada10597917e9776fbd47abf40f06a76c0dff42eada10597917e9776fbd4
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < b1ad04da7fe4515e2ce2d5f2dcab3b5b6d45614bb1ad04da7fe4515e2ce2d5f2dcab3b5b6d45614b
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < a8e2fc8f7b41fa9d9ca5f624f4e4d34fce5b40a9a8e2fc8f7b41fa9d9ca5f624f4e4d34fce5b40a9
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < 0e07032b4b4724b8ad1003698cb81083c18189990e07032b4b4724b8ad1003698cb81083c1818999
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < 5af16182c5639349415118e9e9aecd8355f7a08b5af16182c5639349415118e9e9aecd8355f7a08b
linuxlinux>= 27979bb2ff748613dba96ae66392a76fb0678527 < ef575281b21e9a34dfae544a187c6aac2ae424a9ef575281b21e9a34dfae544a187c6aac2ae424a9
linuxlinux_kernel< 4.9.3344.9.334
linuxlinux_kernel>= 0 < 5.10.158-15.10.158-1
linuxlinux_kernel>= 0 < 6.0.10-16.0.10-1
linuxlinux_kernel>= 0 < 6.0.10-16.0.10-1
linuxlinux_kernel>= 0 < 6.0.10-16.0.10-1
linuxlinux_kernel>= 4.10 < 4.14.3004.14.300
linuxlinux_kernel>= 4.15 < 4.19.2674.19.267
linuxlinux_kernel>= 4.20 < 5.4.2255.4.225
linuxlinux_kernel>= 5.11 < 5.15.805.15.80
linuxlinux_kernel>= 5.16 < 6.0.106.0.10
linuxlinux_kernel>= 5.5 < 5.10.1565.10.156

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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