| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47613: i2c: virtio: fix completion handling |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| i2c: virtio: fix completion handling |
| |
| The driver currently assumes that the notify callback is only received |
| when the device is done with all the queued buffers. |
| |
| However, this is not true, since the notify callback could be called |
| without any of the queued buffers being completed (for example, with |
| virtio-pci and shared interrupts) or with only some of the buffers being |
| completed (since the driver makes them available to the device in |
| multiple separate virtqueue_add_sgs() calls). |
| |
| This can lead to incorrect data on the I2C bus or memory corruption in |
| the guest if the device operates on buffers which are have been freed by |
| the driver. (The WARN_ON in the driver is also triggered.) |
| |
| BUG kmalloc-128 (Tainted: G W ): Poison overwritten |
| First byte 0x0 instead of 0x6b |
| Allocated in i2cdev_ioctl_rdwr+0x9d/0x1de age=243 cpu=0 pid=28 |
| memdup_user+0x2e/0xbd |
| i2cdev_ioctl_rdwr+0x9d/0x1de |
| i2cdev_ioctl+0x247/0x2ed |
| vfs_ioctl+0x21/0x30 |
| sys_ioctl+0xb18/0xb41 |
| Freed in i2cdev_ioctl_rdwr+0x1bb/0x1de age=68 cpu=0 pid=28 |
| kfree+0x1bd/0x1cc |
| i2cdev_ioctl_rdwr+0x1bb/0x1de |
| i2cdev_ioctl+0x247/0x2ed |
| vfs_ioctl+0x21/0x30 |
| sys_ioctl+0xb18/0xb41 |
| |
| Fix this by calling virtio_get_buf() from the notify handler like other |
| virtio drivers and by actually waiting for all the buffers to be |
| completed. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47613 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.15 with commit 3cfc88380413d20f777dc6648a38f683962e52bf and fixed in 5.15.10 with commit 9cbb957441ed8873577d7d313a3d79d69f1dad5c |
| Issue introduced in 5.15 with commit 3cfc88380413d20f777dc6648a38f683962e52bf and fixed in 5.16 with commit b503de239f62eca898cfb7e820d9a35499137d22 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47613 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/i2c/busses/i2c-virtio.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/9cbb957441ed8873577d7d313a3d79d69f1dad5c |
| https://git.kernel.org/stable/c/b503de239f62eca898cfb7e820d9a35499137d22 |
