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| author | Johan Hovold <johan+linaro@kernel.org> | 2022-12-16 12:15:14 +0300 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-12-20 05:13:45 +0300 |
| commit | 41a15855c1ee390a0ae9d0c29d32b451dd30a600 (patch) | |
| tree | d3e2b4f0e9024d7b9d385782e18bcdaedbf1069b | |
| parent | 6bb20c152b6bf7dd8ffb248f33c2593fd9aeb318 (diff) | |
| download | linux-41a15855c1ee390a0ae9d0c29d32b451dd30a600.tar.xz | |
efi: random: fix NULL-deref when refreshing seed
Do not try to refresh the RNG seed in case the firmware does not support
setting variables.
This is specifically needed to prevent a NULL-pointer dereference on the
Lenovo X13s with some firmware revisions, or more generally, whenever
the runtime services have been disabled (e.g. efi=noruntime or with
PREEMPT_RT).
Fixes: e7b813b32a42 ("efi: random: refresh non-volatile random seed when RNG is initialized")
Reported-by: Steev Klimaszewski <steev@kali.org>
Reported-by: Bjorn Andersson <andersson@kernel.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
| -rw-r--r-- | drivers/firmware/efi/efi.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 31a4090c66b3..09716eebe8ac 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -429,7 +429,9 @@ static int __init efisubsys_init(void) platform_device_register_simple("efi_secret", 0, NULL, 0); #endif - execute_with_initialized_rng(&refresh_nv_rng_seed_nb); + if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)) + execute_with_initialized_rng(&refresh_nv_rng_seed_nb); + return 0; err_remove_group: |