CVE-2024-36916: blk-iocost: avoid out of bounds shift
In the Linux kernel, the following vulnerability has been resolved:
blk-iocost: avoid out of bounds shift
UBSAN catches undefined behavior in blk-iocost, where sometimes iocg->delay is shifted right by a number that is too large, resulting in undefined behavior on some architectures.
[ 186.556576] ------------[ cut here ]------------ UBSAN: shift-out-of-bounds in block/blk-iocost.c:1366:23 shift exponent 64 is too large for 64-bit type 'u64' (aka 'unsigned long long') CPU: 16 PID: 0 Comm: swapper/16 Tainted: G S E N 6.9.0-0fbk700debugrc2kbuilder0gc85af715cac0 #1 Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F093A23 12/08/2020 Call Trace: <IRQ> dumpstacklvl+0x8f/0xe0 ubsanhandleshiftoutofbounds+0x22c/0x280 iocgkickdelay+0x30b/0x310 ioctimerfn+0x2fb/0x1f80 runtimerbase+0x1b6/0x250 ...
Avoid that undefined behavior by simply taking the "delay = 0" branch if the shift is too large.
I am not sure what the symptoms of an undefined value delay will be, but I suspect it could be more than a little annoying to debug.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2024-36916?
CVE-2024-36916 is classified as a medium severity vulnerability in the Linux kernel.
How do I fix CVE-2024-36916?
To fix CVE-2024-36916, update your Linux kernel to one of the fixed versions: 5.10.223-1, 5.10.234-1, 6.1.123-1, 6.1.128-1, 6.12.12-1, or 6.12.16-1.
Which Linux distributions are affected by CVE-2024-36916?
CVE-2024-36916 affects Debian users of the Linux kernel package.
What does CVE-2024-36916 exploit in the Linux kernel?
CVE-2024-36916 targets undefined behavior in blk-iocost due to an out-of-bounds shift in the code.
Is CVE-2024-36916 being actively exploited in the wild?
Currently, there is no public indication that CVE-2024-36916 is being exploited in active attacks.