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authorJason A. Donenfeld <Jason@zx2c4.com>2020-02-21 11:48:49 +0300
committerIngo Molnar <mingo@kernel.org>2020-02-26 17:31:43 +0300
commitbe36f9e7517e17810ec369626a128d7948942259 (patch)
tree6e406504b5c2be8fd04d103a9a601ec0fa1da316 /drivers/firmware
parent8319e9d5ad98ffccd19f35664382c73cea216193 (diff)
downloadlinux-be36f9e7517e17810ec369626a128d7948942259.tar.xz
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
Diffstat (limited to 'drivers/firmware')
-rw-r--r--drivers/firmware/efi/efi.c4
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");