This is a note to let you know that I've just added the patch titled
efi/arm64: libstub: Deal gracefully with EFI_RNG_PROTOCOL failure
to the 5.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
efi-arm64-libstub-deal-gracefully-with-efi_rng_protocol-failure.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From d32de9130f6c79533508e2c7879f18997bfbe2a0 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
Date: Sat, 26 Sep 2020 10:52:42 +0200
Subject: efi/arm64: libstub: Deal gracefully with EFI_RNG_PROTOCOL failure
From: Ard Biesheuvel <ardb@xxxxxxxxxx>
commit d32de9130f6c79533508e2c7879f18997bfbe2a0 upstream.
Currently, on arm64, we abort on any failure from efi_get_random_bytes()
other than EFI_NOT_FOUND when it comes to setting the physical seed for
KASLR, but ignore such failures when obtaining the seed for virtual
KASLR or for early seeding of the kernel's entropy pool via the config
table. This is inconsistent, and may lead to unexpected boot failures.
So let's permit any failure for the physical seed, and simply report
the error code if it does not equal EFI_NOT_FOUND.
Cc: <stable@xxxxxxxxxxxxxxx> # v5.8+
Reported-by: Heinrich Schuchardt <xypron.glpk@xxxxxx>
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/efi/libstub/arm64-stub.c | 8 +++++---
drivers/firmware/efi/libstub/fdt.c | 4 +---
2 files changed, 6 insertions(+), 6 deletions(-)
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -62,10 +62,12 @@ efi_status_t handle_kernel_image(unsigne
status = efi_get_random_bytes(sizeof(phys_seed),
(u8 *)&phys_seed);
if (status == EFI_NOT_FOUND) {
- efi_info("EFI_RNG_PROTOCOL unavailable, no randomness supplied\n");
+ efi_info("EFI_RNG_PROTOCOL unavailable, KASLR will be disabled\n");
+ efi_nokaslr = true;
} else if (status != EFI_SUCCESS) {
- efi_err("efi_get_random_bytes() failed\n");
- return status;
+ efi_err("efi_get_random_bytes() failed (0x%lx), KASLR will be disabled\n",
+ status);
+ efi_nokaslr = true;
}
} else {
efi_info("KASLR disabled on kernel command line\n");
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -136,7 +136,7 @@ static efi_status_t update_fdt(void *ori
if (status)
goto fdt_set_fail;
- if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
+ if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && !efi_nokaslr) {
efi_status_t efi_status;
efi_status = efi_get_random_bytes(sizeof(fdt_val64),
@@ -145,8 +145,6 @@ static efi_status_t update_fdt(void *ori
status = fdt_setprop_var(fdt, node, "kaslr-seed", fdt_val64);
if (status)
goto fdt_set_fail;
- } else if (efi_status != EFI_NOT_FOUND) {
- return efi_status;
}
}
Patches currently in stable-queue which might be from ardb@xxxxxxxxxx are
queue-5.9/efi-arm64-libstub-deal-gracefully-with-efi_rng_protocol-failure.patch
