Описание
In the Linux kernel, the following vulnerability has been resolved:
virtio_net: Do not send RSS key if it is not supported
There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop.
Running the following command in any QEMU virtual machine with virtionet will reproduce this problem:
This is how the problem happens:
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ethtool_set_rxfh() calls virtnet_set_rxfh()
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virtnet_set_rxfh() calls virtnet_commit_rss_command()
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virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather
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Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
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This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function):
if (!sz) { virtio_error(vdev, "virtio: zero sized buffers a...
In the Linux kernel, the following vulnerability has been resolved:
virtio_net: Do not send RSS key if it is not supported
There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop.
Running the following command in any QEMU virtual machine with virtionet will reproduce this problem:
This is how the problem happens:
-
ethtool_set_rxfh() calls virtnet_set_rxfh()
-
virtnet_set_rxfh() calls virtnet_commit_rss_command()
-
virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather
-
Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size;
-
This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function):
if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are not allowed");
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virtio_error() (also QEMU function) set the device as broken
vdev->broken = true;
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Qemu bails out, and do not repond this crazy kernel.
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The kernel is waiting for the response to come back (function virtnet_send_command())
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The kernel is waiting doing the following :
while (!virtqueue_get_buf(vi->cvq, &tmp) && !virtqueue_is_broken(vi->cvq)) cpu_relax();
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None of the following functions above is true, thus, the kernel loops here forever. Keeping in mind that virtqueue_is_broken() does not look at the qemu
vdev->broken, so, it never realizes that the vitio is broken at QEMU side.
Fix it by not sending RSS commands if the feature is not available in the device.
Ссылки
- https://nvd.nist.gov/vuln/detail/CVE-2024-35981
- https://git.kernel.org/stable/c/059a49aa2e25c58f90b50151f109dd3c4cdb3a47
- https://git.kernel.org/stable/c/28e9a64638cd16bc1ecac9ff74ffeacb9fb652de
- https://git.kernel.org/stable/c/43a71c1b4b3a6d4db857b1435d271540279fc7de
- https://git.kernel.org/stable/c/539a2b995a4ed93125cb0efae0f793b00ab2158b
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: virtio_net: Do not send RSS key if it is not supported There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop. Running the following command in any QEMU virtual machine with virtionet will reproduce this problem: # ethtool -X eth0 hfunc toeplitz This is how the problem happens: 1) ethtool_set_rxfh() calls virtnet_set_rxfh() 2) virtnet_set_rxfh() calls virtnet_commit_rss_command() 3) virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather 4) Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size; 5) This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function): if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are not allowed"); 6) vir...
In the Linux kernel, the following vulnerability has been resolved: virtio_net: Do not send RSS key if it is not supported There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop. Running the following command in any QEMU virtual machine with virtionet will reproduce this problem: # ethtool -X eth0 hfunc toeplitz This is how the problem happens: 1) ethtool_set_rxfh() calls virtnet_set_rxfh() 2) virtnet_set_rxfh() calls virtnet_commit_rss_command() 3) virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather 4) Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size; 5) This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function): if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are not allowed"); 6) vi...
In the Linux kernel, the following vulnerability has been resolved: virtio_net: Do not send RSS key if it is not supported There is a bug when setting the RSS options in virtio_net that can break the whole machine, getting the kernel into an infinite loop. Running the following command in any QEMU virtual machine with virtionet will reproduce this problem: # ethtool -X eth0 hfunc toeplitz This is how the problem happens: 1) ethtool_set_rxfh() calls virtnet_set_rxfh() 2) virtnet_set_rxfh() calls virtnet_commit_rss_command() 3) virtnet_commit_rss_command() populates 4 entries for the rss scatter-gather 4) Since the command above does not have a key, then the last scatter-gatter entry will be zeroed, since rss_key_size == 0. sg_buf_size = vi->rss_key_size; 5) This buffer is passed to qemu, but qemu is not happy with a buffer with zero length, and do the following in virtqueue_map_desc() (QEMU function): if (!sz) { virtio_error(vdev, "virtio: zero sized buffers are
In the Linux kernel, the following vulnerability has been resolved: v ...
Уязвимость функции virtnet_get_rxfh() модуля drivers/net/virtio_net.c ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании