This is a note to let you know that I've just added the patch titled
efi: random: Properly limit the size of the random seed
to the 4.14-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-random-properly-limit-the-size-of-the-random-seed.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ben@xxxxxxxxxxxxxxx Sat Dec 3 14:43:55 2022
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Date: Thu, 1 Dec 2022 00:47:22 +0100
Subject: efi: random: Properly limit the size of the random seed
To: stable@xxxxxxxxxxxxxxx
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>, "Jason A. Donenfeld" <Jason@xxxxxxxxx>, Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
Message-ID: <Y4frikbdKtF5V1WU@xxxxxxxxxxxxxxx>
Content-Disposition: inline
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Commit be36f9e7517e ("efi: READ_ONCE rng seed size before munmap")
added a READ_ONCE() and also changed the call to
add_bootloader_randomness() to use the local size variable. Neither
of these changes was actually needed and this was not backported to
the 4.14 stable branch.
Commit 161a438d730d ("efi: random: reduce seed size to 32 bytes")
reverted the addition of READ_ONCE() and added a limit to the value of
size. This depends on the earlier commit, because size can now differ
from seed->size, but it was wrongly backported to the 4.14 stable
branch by itself.
Apply the missing change to the add_bootloader_randomness() parameter
(except that here we are still using add_device_randomness()).
Fixes: 700485f70e50 ("efi: random: reduce seed size to 32 bytes")
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/firmware/efi/efi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -541,7 +541,7 @@ int __init efi_config_parse_tables(void
seed = early_memremap(efi.rng_seed,
sizeof(*seed) + size);
if (seed != NULL) {
- add_device_randomness(seed->bits, seed->size);
+ add_device_randomness(seed->bits, size);
early_memunmap(seed, sizeof(*seed) + size);
pr_notice("seeding entropy pool\n");
} else {
Patches currently in stable-queue which might be from ben@xxxxxxxxxxxxxxx are
queue-4.14/efi-random-properly-limit-the-size-of-the-random-seed.patch
