dm-integrity: fix buffer overflow in inline mode with large tag size

Overview

In the Linux kernel, the following vulnerability has been resolved:

dm-integrity: fix buffer overflow in inline mode with large tag size

In inline mode, dm_integrity_check and dm_integrity_inline_recheck compute the checksum of each block into an on-stack buffer of HASH_MAX_DIGESTSIZE bytes. integrity_sector_checksum pads its result with zeroes up to the tag size, so if the tag size is larger than HASH_MAX_DIGESTSIZE, the padding runs past the end of the buffer. With CONFIG_STACKPROTECTOR the kernel panics in dm_integrity_check on the first read.

Enlarge both buffers to hold MAX_TAG_SIZE bytes, as commit b93b6643e9b5 ("dm integrity: fix a crash with unusually large tag size") did for integrity_metadata.

Note that this is not a security bug because the buffer overflow can only be triggered by root.

Affected

• Linux >= fb0987682c629c1d2c476f35f6fde405a5e304a4 < 3c7aad85aeb9e28386672e3a009aa2e61f751b86
• Linux >= fb0987682c629c1d2c476f35f6fde405a5e304a4 < 4f0ee735dc68e3e6c4dd9a666d7f7047163c4165
• Linux >= fb0987682c629c1d2c476f35f6fde405a5e304a4 < f49cd7820cd0a96f20e1aa2708adb002124e38a7
• Linux >= fb0987682c629c1d2c476f35f6fde405a5e304a4 < 764b683a6180fd72c931c13fea98d383506a3475
• Linux 6.11

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.