CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HIn the Linux kernel, the following vulnerability has been resolved: ext4: don't zero the entire extent if EXT4_EXT_DATA_PARTIAL_VALID1 When allocating initialized blocks from a large unwritten extent, or when splitting an unwritten extent during end I/O and converting it to initialized, there is currently a potential issue of stale data if the extent needs to be split in the middle. 0 A B N [UUUUUUUUUUUU] U: unwritten extent [--DDDDDDDD--] D: valid data |<- ->| ----> this range needs to be initialized ext4_split_extent() first try to split this extent at B with EXT4_EXT_DATA_ENTIRE_VALID1 and EXT4_EXT_MAY_ZEROOUT flag set, but ext4_split_extent_at() failed to split this extent due to temporary lack of space. It zeroout B to N and mark the entire extent from 0 to N as written. 0 A B N [WWWWWWWWWWWW] W: written extent [SSDDDDDDDDZZ] Z: zeroed, S: stale data ext4_split_extent() then try to split this extent at A with EXT4_EXT_DATA_VALID2 flag set. This time, it split successfully and left a stale written extent from 0 to A. 0 A B N [WW|WWWWWWWWWW] [SS|DDDDDDDDZZ] Fix this by pass EXT4_EXT_DATA_PARTIAL_VALID1 to ext4_split_extent_at() when splitting at B, don't convert the entire extent to written and left it as unwritten after zeroing out B to N. The remaining work is just like the standard two-part split. ext4_split_extent() will pass the EXT4_EXT_DATA_VALID2 flag when it calls ext4_split_extent_at() for the second time, allowing it to properly handle the split. If the split is successful, it will keep extent from 0 to A as unwritten. A flaw was found in the Linux kernel's ext4 filesystem. This vulnerability occurs during the splitting of unwritten data blocks, where a portion of the data may be incorrectly marked as written while still containing stale, uninitialized information. A local attacker could potentially exploit this to access sensitive data that should have been zeroed out, leading to information disclosure.
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality compromise, and data integrity compromise. These vulnerabili…
Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Several of these vulnerabilities can lead to privilege escalation, denial of service, and data confidentiality breaches. The vulnerabilities are bei…
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and data integrity compromise. These vulnerabiliti…
Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Several of these vulnerabilities can lead to data confidentiality and integrity breaches, as well as the circumvention of security policies and deni…
Multiple vulnerabilities have been discovered in the SUSE Linux kernel. Some of these vulnerabilities allow for data confidentiality and integrity breaches, as well as bypassing security policies and causing denial of se…
Multiple vulnerabilities have been discovered in the Linux kernel of Ubuntu. Some of these vulnerabilities allow for privilege escalation, data confidentiality breaches, and denial of service attacks. The vulnerabilities…