In the Linux kernel, the following vulnerability has been resolved:
drivers: core: synchronize really_probe() and dev_uevent()
Synchronize the dev->driver usage in really_probe() and dev_uevent().
These can run in different threads, what can result in the following
race condition for dev->driver uninitialization:
really_probe() {
…
probe_failed:
…
device_unbind_cleanup(dev) {
…
dev->driver = NULL; // <= Failed probe sets dev->driver to NULL
…
}
…
}
dev_uevent() {
…
if (dev->driver)
// If dev->driver is NULLed from really_probe() from here on,
// after above check, the system crashes
add_uevent_var(env, “DRIVER=%s”, dev->driver->name);
…
}
really_probe() holds the lock, already. So nothing needs to be done
there. dev_uevent() is called with lock held, often, too. But not
always. What implies that we can’t add any locking in dev_uevent()
itself. So fix this race by adding the lock to the non-protected
path. This is the path where above race is observed:
dev_uevent+0x235/0x380
uevent_show+0x10c/0x1f0 <= Add lock here
dev_attr_show+0x3a/0xa0
sysfs_kf_seq_show+0x17c/0x250
kernfs_seq_show+0x7c/0x90
seq_read_iter+0x2d7/0x940
kernfs_fop_read_iter+0xc6/0x310
vfs_read+0x5bc/0x6b0
ksys_read+0xeb/0x1b0
__x64_sys_read+0x42/0x50
x64_sys_call+0x27ad/0x2d30
do_syscall_64+0xcd/0x1d0
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Similar cases are reported by syzkaller in
https://syzkaller.appspot.com/bug?extid=ffa8143439596313a85a
But these are regarding the initialization of dev->driver
dev->driver = drv;
As this switches dev->driver to non-NULL these reports can be considered
to be false-positives (which should be “fixed” by this commit, as well,
though).
The same issue was reported and tried to be fixed back in 2015 in
https://lore.kernel.org/lkml/[email protected]/
already.
Vendor | Product | Version | CPE |
---|---|---|---|
linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/base/core.c"
],
"versions": [
{
"version": "239378f16aa1",
"lessThan": "bb3641a58317",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "13d25e82b6d0",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "760603e30bf1",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "ec772ed7cb21",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "08891eeaa97c",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "a42b0060d6ff",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "95d03d369ea6",
"status": "affected",
"versionType": "git"
},
{
"version": "239378f16aa1",
"lessThan": "c0a40097f0bc",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"drivers/base/core.c"
],
"versions": [
{
"version": "2.6.21",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.21",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "4.19.317",
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.4.279",
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.221",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.162",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.1.95",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.35",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.9.6",
"lessThanOrEqual": "6.9.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.10",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]
git.kernel.org/stable/c/08891eeaa97c079b7f95d60b62dcf0e3ce034b69
git.kernel.org/stable/c/13d25e82b6d00d743c7961dcb260329f86bedf7c
git.kernel.org/stable/c/760603e30bf19d7b4c28e9d81f18b54fa3b745ad
git.kernel.org/stable/c/95d03d369ea647b89e950667f1c3363ea6f564e6
git.kernel.org/stable/c/a42b0060d6ff2f7e59290a26d5f162a3c6329b90
git.kernel.org/stable/c/bb3641a5831789d83a58a39ed4a928bcbece7080
git.kernel.org/stable/c/c0a40097f0bc81deafc15f9195d1fb54595cd6d0
git.kernel.org/stable/c/ec772ed7cb21b46fb132f89241682553efd0b721