From bippy-a5840b7849dd Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2024-36916: blk-iocost: avoid out of bounds shift Description =========== 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 6.9.0-0_fbk700_debug_rc2_kbuilder_0_gc85af715cac0 #1 Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F09_3A23 12/08/2020 Call Trace: dump_stack_lvl+0x8f/0xe0 __ubsan_handle_shift_out_of_bounds+0x22c/0x280 iocg_kick_delay+0x30b/0x310 ioc_timer_fn+0x2fb/0x1f80 __run_timer_base+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. The Linux kernel CVE team has assigned CVE-2024-36916 to this issue. Affected and fixed versions =========================== Fixed in 5.10.217 with commit 62accf6c1d7b Fixed in 5.15.159 with commit 844fc023e9f1 Fixed in 6.1.91 with commit f6add0a6f78d Fixed in 6.6.31 with commit ce0e99cae00e Fixed in 6.8.10 with commit 488dc6808cb8 Fixed in 6.9 with commit beaa51b36012 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2024-36916 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: block/blk-iocost.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/62accf6c1d7b433752cb3591bba8967b7a801ad5 https://git.kernel.org/stable/c/844fc023e9f14a4fb1de5ae1eaefafd6d69c5fa1 https://git.kernel.org/stable/c/f6add0a6f78dc6360b822ca4b6f9f2f14174c8ca https://git.kernel.org/stable/c/ce0e99cae00e3131872936713b7f55eefd53ab86 https://git.kernel.org/stable/c/488dc6808cb8369685f18cee81e88e7052ac153b https://git.kernel.org/stable/c/beaa51b36012fad5a4d3c18b88a617aea7a9b96d