CVE-2024-46798

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

ASoC: dapm: Fix UAF for sndsocpcm_runtime object

When using kernel with the following extra config,

• CONFIG_KASAN=y
• CONFIGKASANGENERIC=y
• CONFIGKASANINLINE=y
• CONFIGKASANVMALLOC=y
• CONFIGFRAMEWARN=4096

kernel detects that sndpcmsuspendall() access a freed 'sndsocpcmruntime' object when the system is suspended, which leads to a use-after-free bug:

[ 52.047746] BUG: KASAN: use-after-free in sndpcmsuspend_all+0x1a8/0x270 [ 52.047765] Read of size 1 at addr ffff0000b9434d50 by task systemd-sleep/2330

[ 52.047785] Call trace: [ 52.047787] dumpbacktrace+0x0/0x3c0 [ 52.047794] showstack+0x34/0x50 [ 52.047797] dumpstacklvl+0x68/0x8c [ 52.047802] printaddressdescription.constprop.0+0x74/0x2c0 [ 52.047809] kasan_report+0x210/0x230 [ 52.047815] __asanreportload1noabort+0x3c/0x50 [ 52.047820] sndpcmsuspendall+0x1a8/0x270 [ 52.047824] sndsocsuspend+0x19c/0x4e0

The sndpcmsync_stop() has a NULL check on 'substream->runtime' before making any access. So we need to always set 'substream->runtime' to NULL everytime we kfree() it.