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	Sparse gets cross about us returning 0 from image_load(), which has a
return type of 'void *':
>> arch/arm64/kernel/kexec_image.c:130:16: sparse: sparse: Using plain integer as NULL pointer
Return NULL instead, as we don't use the return value for anything if it
does not indicate an error.
Cc: Benjamin Gwin <bgwin@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 108aa50365 ("arm64: kexec_file: try more regions if loading segments fails")
Link: https://lore.kernel.org/r/202011091736.T0zH8kaC-lkp@intel.com
Signed-off-by: Will Deacon <will@kernel.org>
		
	
			
		
			
				
	
	
		
			147 lines
		
	
	
	
		
			4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			147 lines
		
	
	
	
		
			4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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/*
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 * Kexec image loader
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 * Copyright (C) 2018 Linaro Limited
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 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
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 */
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#define pr_fmt(fmt)	"kexec_file(Image): " fmt
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/kexec.h>
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#include <linux/pe.h>
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#include <linux/string.h>
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#include <linux/verification.h>
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#include <asm/byteorder.h>
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#include <asm/cpufeature.h>
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#include <asm/image.h>
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#include <asm/memory.h>
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static int image_probe(const char *kernel_buf, unsigned long kernel_len)
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{
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	const struct arm64_image_header *h =
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		(const struct arm64_image_header *)(kernel_buf);
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	if (!h || (kernel_len < sizeof(*h)))
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		return -EINVAL;
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	if (memcmp(&h->magic, ARM64_IMAGE_MAGIC, sizeof(h->magic)))
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		return -EINVAL;
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	return 0;
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}
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static void *image_load(struct kimage *image,
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				char *kernel, unsigned long kernel_len,
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				char *initrd, unsigned long initrd_len,
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				char *cmdline, unsigned long cmdline_len)
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{
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	struct arm64_image_header *h;
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	u64 flags, value;
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	bool be_image, be_kernel;
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	struct kexec_buf kbuf;
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	unsigned long text_offset, kernel_segment_number;
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	struct kexec_segment *kernel_segment;
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	int ret;
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	/*
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	 * We require a kernel with an unambiguous Image header. Per
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	 * Documentation/arm64/booting.rst, this is the case when image_size
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	 * is non-zero (practically speaking, since v3.17).
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	 */
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	h = (struct arm64_image_header *)kernel;
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	if (!h->image_size)
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		return ERR_PTR(-EINVAL);
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	/* Check cpu features */
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	flags = le64_to_cpu(h->flags);
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	be_image = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_BE);
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	be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
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	if ((be_image != be_kernel) && !system_supports_mixed_endian())
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		return ERR_PTR(-EINVAL);
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	value = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_PAGE_SIZE);
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	if (((value == ARM64_IMAGE_FLAG_PAGE_SIZE_4K) &&
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			!system_supports_4kb_granule()) ||
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	    ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_64K) &&
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			!system_supports_64kb_granule()) ||
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	    ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_16K) &&
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			!system_supports_16kb_granule()))
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		return ERR_PTR(-EINVAL);
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	/* Load the kernel */
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	kbuf.image = image;
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	kbuf.buf_min = 0;
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	kbuf.buf_max = ULONG_MAX;
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	kbuf.top_down = false;
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	kbuf.buffer = kernel;
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	kbuf.bufsz = kernel_len;
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	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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	kbuf.memsz = le64_to_cpu(h->image_size);
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	text_offset = le64_to_cpu(h->text_offset);
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	kbuf.buf_align = MIN_KIMG_ALIGN;
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	/* Adjust kernel segment with TEXT_OFFSET */
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	kbuf.memsz += text_offset;
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	kernel_segment_number = image->nr_segments;
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	/*
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	 * The location of the kernel segment may make it impossible to satisfy
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	 * the other segment requirements, so we try repeatedly to find a
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	 * location that will work.
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	 */
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	while ((ret = kexec_add_buffer(&kbuf)) == 0) {
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		/* Try to load additional data */
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		kernel_segment = &image->segment[kernel_segment_number];
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		ret = load_other_segments(image, kernel_segment->mem,
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					  kernel_segment->memsz, initrd,
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					  initrd_len, cmdline);
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		if (!ret)
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			break;
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		/*
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		 * We couldn't find space for the other segments; erase the
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		 * kernel segment and try the next available hole.
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		 */
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		image->nr_segments -= 1;
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		kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz;
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		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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	}
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	if (ret) {
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		pr_err("Could not find any suitable kernel location!");
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		return ERR_PTR(ret);
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	}
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	kernel_segment = &image->segment[kernel_segment_number];
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	kernel_segment->mem += text_offset;
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	kernel_segment->memsz -= text_offset;
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	image->start = kernel_segment->mem;
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	pr_debug("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
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				kernel_segment->mem, kbuf.bufsz,
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				kernel_segment->memsz);
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	return NULL;
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}
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#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
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static int image_verify_sig(const char *kernel, unsigned long kernel_len)
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{
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	return verify_pefile_signature(kernel, kernel_len, NULL,
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				       VERIFYING_KEXEC_PE_SIGNATURE);
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}
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#endif
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const struct kexec_file_ops kexec_image_ops = {
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	.probe = image_probe,
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	.load = image_load,
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#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
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	.verify_sig = image_verify_sig,
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#endif
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};
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