diff options
| author | Justin Hibbits <jhibbits@FreeBSD.org> | 2026-04-22 15:51:06 +0000 |
|---|---|---|
| committer | Justin Hibbits <jhibbits@FreeBSD.org> | 2026-04-22 16:28:54 +0000 |
| commit | e3e8ec2ab620f026b42b4988fce49eff7cec16eb (patch) | |
| tree | c19e43e292977a8204b7e65dae6eb480bb2540a7 | |
| parent | 69cc351c4c911cfeda1851f3c18a4b61281708cb (diff) | |
kexec: Disallow kexec_load if securelevel > 0
kexec_load() + reboot is intended to be equivalent to a system reboot.
However kexec_load() can load arbitrary data as the target kernel,
leading to execution of arbitrary code, even though it's effectively in
a new context. Rather than being equivalent to a system reboot, it's
also equivalent to kldload(), which loads arbitrary code into the
running kernel. Since kldload() is blocked at securelevel 1, also block
kexec_load().
Reported by: markj
Fixes: e02c57ff3 ("kern: Introduce kexec system feature (MI)")
Sponsored by: Hewlett Packard Enterprise
Differential Revision: https://reviews.freebsd.org/D56580
| -rw-r--r-- | sys/kern/kern_kexec.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sys/kern/kern_kexec.c b/sys/kern/kern_kexec.c index 86ee9da9a606..5ba76512e963 100644 --- a/sys/kern/kern_kexec.c +++ b/sys/kern/kern_kexec.c @@ -342,6 +342,9 @@ sys_kexec_load(struct thread *td, struct kexec_load_args *uap) { int error; + error = securelevel_gt(td->td_ucred, 0); + if (error != 0) + return (error); // FIXME: Do w need a better privilege check than PRIV_REBOOT here? error = priv_check(td, PRIV_REBOOT); if (error != 0) |