Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 136d5d57 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Ingo Molnar
Browse files

efi/esrt: Fix handling of early ESRT table mapping 



As reported by Tyler, efi_esrt_init() will return without releasing the
ESRT table header mapping if it encounters a table with an unexpected
version. Replacing the 'return' with 'goto err_memunmap' would fix this
particular occurrence, but, as it turns out, the code is rather peculiar
to begin with:

 - it never uses the header mapping after memcpy()'ing out its contents,
 - it maps and unmaps the entire table without ever looking at the
   contents.

So let's refactor this code to unmap the table header right after the
memcpy() so we can get rid of the error handling path altogether, and
drop the second mapping entirely.

Reported-by: default avatarTyler Baicar <tbaicar@codeaurora.org>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180312084500.10764-5-ard.biesheuvel@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7e904a91

drivers/firmware/efi/esrt.c

+4 −13
Original line number Diff line number Diff line
@@ -279,6 +279,7 @@ void __init efi_esrt_init(void) 
	}



	memcpy(&tmpesrt, va, sizeof(tmpesrt));

	early_memunmap(va, size);



	if (tmpesrt.fw_resource_version == 1) {

		entry_size = sizeof (*v1_entries);
@@ -291,7 +292,7 @@ void __init efi_esrt_init(void) 
	if (tmpesrt.fw_resource_count > 0 && max - size < entry_size) {

		pr_err("ESRT memory map entry can only hold the header. (max: %zu size: %zu)\n",

		       max - size, entry_size);

		goto err_memunmap;

		return;

	}



	/*
@@ -304,7 +305,7 @@ void __init efi_esrt_init(void) 
	if (tmpesrt.fw_resource_count > 128) {

		pr_err("ESRT says fw_resource_count has very large value %d.\n",

		       tmpesrt.fw_resource_count);

		goto err_memunmap;

		return;

	}



	/*
@@ -315,18 +316,10 @@ void __init efi_esrt_init(void) 
	if (max < size + entries_size) {

		pr_err("ESRT does not fit on single memory map entry (size: %zu max: %zu)\n",

		       size, max);

		goto err_memunmap;

		return;

	}



	/* remap it with our (plausible) new pages */

	early_memunmap(va, size);

	size += entries_size;

	va = early_memremap(efi.esrt, size);

	if (!va) {

		pr_err("early_memremap(%p, %zu) failed.\n", (void *)efi.esrt,

		       size);

		return;

	}



	esrt_data = (phys_addr_t)efi.esrt;

	esrt_data_size = size;
@@ -336,8 +329,6 @@ void __init efi_esrt_init(void) 
	efi_mem_reserve(esrt_data, esrt_data_size);



	pr_debug("esrt-init: loaded.\n");

err_memunmap:

	early_memunmap(va, size);

}



static int __init register_entries(void)