CVE-2024-49933: blk_iocost: fix more out of bound shifts
In the Linux kernel, the following vulnerability has been resolved:
blkiocost: fix more out of bound shifts
Recently running UBSAN caught few out of bound shifts in the iocforgivedebts() function:
UBSAN: shift-out-of-bounds in block/blk-iocost.c:2142:38 shift exponent 80 is too large for 64-bit type 'u64' (aka 'unsigned long long') ... UBSAN: shift-out-of-bounds in block/blk-iocost.c:2144:30 shift exponent 80 is too large for 64-bit type 'u64' (aka 'unsigned long long') ... Call Trace: <IRQ> dumpstacklvl+0xca/0x130 ubsanhandleshiftoutofbounds+0x22c/0x280 ? lockacquire+0x6441/0x7c10 ioctimerfn+0x6cec/0x7750 ? blkiocostinit+0x720/0x720 ? calltimerfn+0x5d/0x470 calltimerfn+0xfa/0x470 ? blkiocostinit+0x720/0x720 runtimerbase+0x519/0x700 ...
Actual impact of this issue was not identified but I propose to fix the undefined behaviour. The proposed fix to prevent those out of bound shifts consist of precalculating exponent before using it the shift operations by taking min value from the actual exponent and maximum possible number of bits.
Other sources
In the Linux kernel, the following vulnerability has been resolved:
blkiocost: fix more out of bound shifts
Recently running UBSAN caught few out of bound shifts in the iocforgivedebts() function:
UBSAN: shift-out-of-bounds in block/blk-iocost.c:2142:38 shift exponent 80 is too large for 64-bit type 'u64' (aka 'unsigned long long') ... UBSAN: shift-out-of-bounds in block/blk-iocost.c:2144:30 shift exponent 80 is too large for 64-bit type 'u64' (aka 'unsigned long long') ... Call Trace: <IRQ> dumpstacklvl+0xca/0x130 ubsanhandleshiftoutofbounds+0x22c/0x280 ? lockacquire+0x6441/0x7c10 ioctimerfn+0x6cec/0x7750 ? blkiocostinit+0x720/0x720 ? calltimerfn+0x5d/0x470 calltimerfn+0xfa/0x470 ? blkiocostinit+0x720/0x720 runtimerbase+0x519/0x700 ...
Actual impact of this issue was not identified but I propose to fix the undefined behaviour. The proposed fix to prevent those out of bound shifts consist of precalculating exponent before using it the shift operations by taking min value from the actual exponent and maximum possible number of bits.
— NVD
This CVE was automatically created from a reference found in an email or other text. If you are reading this, then this CVE entry is probably erroneous, since this text should be replaced by the official CVE description automatically.
— Launchpad
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2024-49933?
CVE-2024-49933 has a medium severity level due to its potential to cause system instability.
What versions of Linux Kernel are affected by CVE-2024-49933?
CVE-2024-49933 affects Linux Kernel versions prior to 5.10.227 and between 5.11 to 5.15.168, 5.16 to 6.1.113, 6.2 to 6.6.55, 6.7 to 6.10.14, and 6.11 to 6.11.3.
How do I fix CVE-2024-49933?
To fix CVE-2024-49933, update your Linux Kernel to a version equal to or greater than 6.12.11-1 or apply the necessary patch provided in the remediation packages.
What specific function in the Linux Kernel is vulnerable in CVE-2024-49933?
The vulnerable function in CVE-2024-49933 is ioc_forgive_debts() located in block/blk-iocost.c.
Does CVE-2024-49933 require special conditions to be exploited?
CVE-2024-49933 can be triggered during specific I/O operations, making it susceptible to exploitation under certain system workloads.