Commit f91b1fea authored Jul 26, 2015 by Ard Biesheuvel Committed by Catalin Marinas Jul 27, 2015

arm64/efi: map the entire UEFI vendor string before reading it



At boot, the UTF-16 UEFI vendor string is copied from the system
table into a char array with a size of 100 bytes. However, this
size of 100 bytes is also used for memremapping() the source,
which may not be sufficient if the vendor string exceeds 50
UTF-16 characters, and the placement of the vendor string inside
a 4 KB page happens to leave the end unmapped.

So use the correct '100 * sizeof(efi_char16_t)' for the size of
the mapping.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Fixes: f84d0275 ("arm64: add EFI runtime services")
Cc: <stable@vger.kernel.org> # 3.16+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent cbfe8fa6

arch/arm64/kernel/efi.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -122,12 +122,12 @@ static int __init uefi_init(void)

		/* Show what we know for posterity */
		c16 = early_memremap(efi_to_phys(efi.systab->fw_vendor),
		sizeof(vendor));
		sizeof(vendor) * sizeof(efi_char16_t));
		if (c16) {
		for (i = 0; i < (int) sizeof(vendor) - 1 && *c16; ++i)
		vendor[i] = c16[i];
		vendor[i] = '\0';
		early_memunmap(c16, sizeof(vendor));
		early_memunmap(c16, sizeof(vendor) * sizeof(efi_char16_t));
		}

		pr_info("EFI v%u.%.02u by %s\n",