From: Ben Hutchings Date: Thu, 1 Dec 2022 00:28:51 +0100 Subject: efi: random: Properly limit the size of the random seed Forwarded: https://lore.kernel.org/stable/Y4fq5mGUbcKV8VwM@decadent.org.uk/T/ 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 4.19 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 4.19 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: 0513592520ae ("efi: random: reduce seed size to 32 bytes") Signed-off-by: Ben Hutchings --- 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 @@ -570,7 +570,7 @@ int __init efi_config_parse_tables(void sizeof(*seed) + size); if (seed != NULL) { pr_notice("seeding entropy pool\n"); - add_device_randomness(seed->bits, seed->size); + add_device_randomness(seed->bits, size); early_memunmap(seed, sizeof(*seed) + size); } else { pr_err("Could not map UEFI random seed!\n");