UBUNTU-CVE-2018-1000204

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UBUNTU-CVE-2018-1000204

Summary:

Details: Linux Kernel version 3.18 to 4.16 incorrectly handles an SG_IO ioctl on /dev/sg0 with dxfer_direction=SG_DXFER_FROM_DEV and an empty 6-byte cmdp. This may lead to copying up to 1000 kernel heap pages to the userspace. This has been fixed upstream in https://github.com/torvalds/linux/commit/a45b599ad808c3c982fdcdc12b0b8611c2f92824 already. The problem has limited scope, as users don't usually have permissions to access SCSI devices. On the other hand, e.g. the Nero user manual suggests doing `chmod o+r+w /dev/sg*` to make the devices accessible. NOTE: third parties dispute the relevance of this report, noting that the requirement for an attacker to have both the CAP_SYS_ADMIN and CAP_SYS_RAWIO capabilities makes it "virtually impossible to exploit.

References: https://ubuntu.com/security/CVE-2018-1000204, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a45b599ad808c3c982fdcdc12b0b8611c2f92824, https://ubuntu.com/security/notices/USN-3696-1, https://ubuntu.com/security/notices/USN-3696-2, https://ubuntu.com/security/notices/USN-3752-1, https://ubuntu.com/security/notices/USN-3752-2, https://ubuntu.com/security/notices/USN-3754-1, https://ubuntu.com/security/notices/USN-3752-3, https://www.cve.org/CVERecord?id=CVE-2018-1000204