diff options
| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2020-02-21 09:48:49 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-02-26 15:31:43 +0100 |
| commit | be36f9e7517e17810ec369626a128d7948942259 (patch) | |
| tree | 6e406504b5c2be8fd04d103a9a601ec0fa1da316 | |
| parent | 8319e9d5ad98ffccd19f35664382c73cea216193 (diff) | |
efi: READ_ONCE rng seed size before munmap
This function is consistent with using size instead of seed->size
(except for one place that this patch fixes), but it reads seed->size
without using READ_ONCE, which means the compiler might still do
something unwanted. So, this commit simply adds the READ_ONCE
wrapper.
Fixes: 636259880a7e ("efi: Add support for seeding the RNG from a UEFI ...")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-efi@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200217123354.21140-1-Jason@zx2c4.com
Link: https://lore.kernel.org/r/20200221084849.26878-5-ardb@kernel.org
| -rw-r--r-- | drivers/firmware/efi/efi.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 621220ab3d0e..21ea99f65113 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -552,7 +552,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, seed = early_memremap(efi.rng_seed, sizeof(*seed)); if (seed != NULL) { - size = seed->size; + size = READ_ONCE(seed->size); early_memunmap(seed, sizeof(*seed)); } else { pr_err("Could not map UEFI random seed!\n"); @@ -562,7 +562,7 @@ int __init efi_config_parse_tables(void *config_tables, int count, int sz, sizeof(*seed) + size); if (seed != NULL) { pr_notice("seeding entropy pool\n"); - add_bootloader_randomness(seed->bits, seed->size); + add_bootloader_randomness(seed->bits, size); early_memunmap(seed, sizeof(*seed) + size); } else { pr_err("Could not map UEFI random seed!\n"); |