cregit-Linux how code gets into the kernel

Release 4.17 kernel/kexec_file.c

Directory: kernel
/*
 * kexec: kexec_file_load system call
 *
 * Copyright (C) 2014 Red Hat Inc.
 * Authors:
 *      Vivek Goyal <vgoyal@redhat.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/capability.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/kexec.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/ima.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/vmalloc.h>
#include "kexec_internal.h"

static int kexec_calculate_store_digests(struct kimage *image);

/*
 * Currently this is the only default function that is exported as some
 * architectures need it to do additional handlings.
 * In the future, other default functions may be exported too if required.
 */

int kexec_image_probe_default(struct kimage *image, void *buf, unsigned long buf_len) { const struct kexec_file_ops * const *fops; int ret = -ENOEXEC; for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) { ret = (*fops)->probe(buf, buf_len); if (!ret) { image->fops = *fops; return ret; } } return ret; }

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/* Architectures can provide this probe function */
int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, unsigned long buf_len) { return kexec_image_probe_default(image, buf, buf_len); }

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AKASHI Takahiro1034.48%150.00%
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static void *kexec_image_load_default(struct kimage *image) { if (!image->fops || !image->fops->load) return ERR_PTR(-ENOEXEC); return image->fops->load(image, image->kernel_buf, image->kernel_buf_len, image->initrd_buf, image->initrd_buf_len, image->cmdline_buf, image->cmdline_buf_len); }

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AKASHI Takahiro6394.03%150.00%
Dave Young45.97%150.00%
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void * __weak arch_kexec_kernel_image_load(struct kimage *image) { return kexec_image_load_default(image); }

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Dave Young1372.22%150.00%
AKASHI Takahiro527.78%150.00%
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static int kexec_image_post_load_cleanup_default(struct kimage *image) { if (!image->fops || !image->fops->cleanup) return 0; return image->fops->cleanup(image->image_loader_data); }

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AKASHI Takahiro3792.50%150.00%
Dave Young37.50%150.00%
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int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) { return kexec_image_post_load_cleanup_default(image); }

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Dave Young1376.47%150.00%
AKASHI Takahiro423.53%150.00%
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#ifdef CONFIG_KEXEC_VERIFY_SIG
static int kexec_image_verify_sig_default(struct kimage *image, void *buf, unsigned long buf_len) { if (!image->fops || !image->fops->verify_sig) { pr_debug("kernel loader does not support signature verification.\n"); return -EKEYREJECTED; } return image->fops->verify_sig(buf, buf_len); }

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AKASHI Takahiro56100.00%1100.00%
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int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, unsigned long buf_len) { return kexec_image_verify_sig_default(image, buf, buf_len); }

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#endif /* * arch_kexec_apply_relocations_add - apply relocations of type RELA * @pi: Purgatory to be relocated. * @section: Section relocations applying to. * @relsec: Section containing RELAs. * @symtab: Corresponding symtab. * * Return: 0 on success, negative errno on error. */
int __weak arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section, const Elf_Shdr *relsec, const Elf_Shdr *symtab) { pr_err("RELA relocation unsupported.\n"); return -ENOEXEC; }

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Dave Young2264.71%150.00%
Philipp Rudo1235.29%150.00%
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/* * arch_kexec_apply_relocations - apply relocations of type REL * @pi: Purgatory to be relocated. * @section: Section relocations applying to. * @relsec: Section containing RELs. * @symtab: Corresponding symtab. * * Return: 0 on success, negative errno on error. */
int __weak arch_kexec_apply_relocations(struct purgatory_info *pi, Elf_Shdr *section, const Elf_Shdr *relsec, const Elf_Shdr *symtab) { pr_err("REL relocation unsupported.\n"); return -ENOEXEC; }

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Dave Young2264.71%150.00%
Philipp Rudo1235.29%150.00%
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/* * Free up memory used by kernel, initrd, and command line. This is temporary * memory allocation which is not needed any more after these buffers have * been loaded into separate segments and have been copied elsewhere. */
void kimage_file_post_load_cleanup(struct kimage *image) { struct purgatory_info *pi = &image->purgatory_info; vfree(image->kernel_buf); image->kernel_buf = NULL; vfree(image->initrd_buf); image->initrd_buf = NULL; kfree(image->cmdline_buf); image->cmdline_buf = NULL; vfree(pi->purgatory_buf); pi->purgatory_buf = NULL; vfree(pi->sechdrs); pi->sechdrs = NULL; /* See if architecture has anything to cleanup post load */ arch_kimage_file_post_load_cleanup(image); /* * Above call should have called into bootloader to free up * any data stored in kimage->image_loader_data. It should * be ok now to free it up. */ kfree(image->image_loader_data); image->image_loader_data = NULL; }

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Dave Young105100.00%1100.00%
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/* * In file mode list of segments is prepared by kernel. Copy relevant * data from user space, do error checking, prepare segment list */
static int kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, const char __user *cmdline_ptr, unsigned long cmdline_len, unsigned flags) { int ret = 0; void *ldata; loff_t size; ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf, &size, INT_MAX, READING_KEXEC_IMAGE); if (ret) return ret; image->kernel_buf_len = size; /* IMA needs to pass the measurement list to the next kernel. */ ima_add_kexec_buffer(image); /* Call arch image probe handlers */ ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, image->kernel_buf_len); if (ret) goto out; #ifdef CONFIG_KEXEC_VERIFY_SIG ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, image->kernel_buf_len); if (ret) { pr_debug("kernel signature verification failed.\n"); goto out; } pr_debug("kernel signature verification successful.\n"); #endif /* It is possible that there no initramfs is being loaded */ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf, &size, INT_MAX, READING_KEXEC_INITRAMFS); if (ret) goto out; image->initrd_buf_len = size; } if (cmdline_len) { image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len); if (IS_ERR(image->cmdline_buf)) { ret = PTR_ERR(image->cmdline_buf); image->cmdline_buf = NULL; goto out; } image->cmdline_buf_len = cmdline_len; /* command line should be a string with last byte null */ if (image->cmdline_buf[cmdline_len - 1] != '\0') { ret = -EINVAL; goto out; } } /* Call arch image load handlers */ ldata = arch_kexec_kernel_image_load(image); if (IS_ERR(ldata)) { ret = PTR_ERR(ldata); goto out; } image->image_loader_data = ldata; out: /* In case of error, free up all allocated memory in this function */ if (ret) kimage_file_post_load_cleanup(image); return ret; }

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Dave Young26685.81%125.00%
Mimi Zohar3310.65%250.00%
Al Viro113.55%125.00%
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static int kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, int initrd_fd, const char __user *cmdline_ptr, unsigned long cmdline_len, unsigned long flags) { int ret; struct kimage *image; bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; image = do_kimage_alloc_init(); if (!image) return -ENOMEM; image->file_mode = 1; if (kexec_on_panic) { /* Enable special crash kernel control page alloc policy. */ image->control_page = crashk_res.start; image->type = KEXEC_TYPE_CRASH; } ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, cmdline_ptr, cmdline_len, flags); if (ret) goto out_free_image; ret = sanity_check_segment_list(image); if (ret) goto out_free_post_load_bufs; ret = -ENOMEM; image->control_code_page = kimage_alloc_control_pages(image, get_order(KEXEC_CONTROL_PAGE_SIZE)); if (!image->control_code_page) { pr_err("Could not allocate control_code_buffer\n"); goto out_free_post_load_bufs; } if (!kexec_on_panic) { image->swap_page = kimage_alloc_control_pages(image, 0); if (!image->swap_page) { pr_err("Could not allocate swap buffer\n"); goto out_free_control_pages; } } *rimage = image; return 0; out_free_control_pages: kimage_free_page_list(&image->control_pages); out_free_post_load_bufs: kimage_file_post_load_cleanup(image); out_free_image: kfree(image); return ret; }

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Dave Young232100.00%1100.00%
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SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags) { int ret = 0, i; struct kimage **dest_image, *image; /* We only trust the superuser with rebooting the system. */ if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) return -EPERM; /* Make sure we have a legal set of flags */ if (flags != (flags & KEXEC_FILE_FLAGS)) return -EINVAL; image = NULL; if (!mutex_trylock(&kexec_mutex)) return -EBUSY; dest_image = &kexec_image; if (flags & KEXEC_FILE_ON_CRASH) { dest_image = &kexec_crash_image; if (kexec_crash_image) arch_kexec_unprotect_crashkres(); } if (flags & KEXEC_FILE_UNLOAD) goto exchange; /* * In case of crash, new kernel gets loaded in reserved region. It is * same memory where old crash kernel might be loaded. Free any * current crash dump kernel before we corrupt it. */ if (flags & KEXEC_FILE_ON_CRASH) kimage_free(xchg(&kexec_crash_image, NULL)); ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, cmdline_len, flags); if (ret) goto out; ret = machine_kexec_prepare(image); if (ret) goto out; /* * Some architecture(like S390) may touch the crash memory before * machine_kexec_prepare(), we must copy vmcoreinfo data after it. */ ret = kimage_crash_copy_vmcoreinfo(image); if (ret) goto out; ret = kexec_calculate_store_digests(image); if (ret) goto out; for (i = 0; i < image->nr_segments; i++) { struct kexec_segment *ksegment; ksegment = &image->segment[i]; pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", i, ksegment->buf, ksegment->bufsz, ksegment->mem, ksegment->memsz); ret = kimage_load_segment(image, &image->segment[i]); if (ret) goto out; } kimage_terminate(image); /* * Free up any temporary buffers allocated which are not needed * after image has been loaded */ kimage_file_post_load_cleanup(image); exchange: image = xchg(dest_image, image); out: if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) arch_kexec_protect_crashkres(); mutex_unlock(&kexec_mutex); kimage_free(image); return ret; }
static int locate_mem_hole_top_down(unsigned long start, unsigned long end, struct kexec_buf *kbuf) { struct kimage *image = kbuf->image; unsigned long temp_start, temp_end; temp_end = min(end, kbuf->buf_max); temp_start = temp_end - kbuf->memsz; do { /* align down start */ temp_start = temp_start & (~(kbuf->buf_align - 1)); if (temp_start < start || temp_start < kbuf->buf_min) return 0; temp_end = temp_start + kbuf->memsz - 1; /* * Make sure this does not conflict with any of existing * segments */ if (kimage_is_destination_range(image, temp_start, temp_end)) { temp_start = temp_start - PAGE_SIZE; continue; } /* We found a suitable memory range */ break; } while (1); /* If we are here, we found a suitable memory range */ kbuf->mem = temp_start; /* Success, stop navigating through remaining System RAM ranges */ return 1; }

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Dave Young136100.00%1100.00%
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static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, struct kexec_buf *kbuf) { struct kimage *image = kbuf->image; unsigned long temp_start, temp_end; temp_start = max(start, kbuf->buf_min); do { temp_start = ALIGN(temp_start, kbuf->buf_align); temp_end = temp_start + kbuf->memsz - 1; if (temp_end > end || temp_end > kbuf->buf_max) return 0; /* * Make sure this does not conflict with any of existing * segments */ if (kimage_is_destination_range(image, temp_start, temp_end)) { temp_start = temp_start + PAGE_SIZE; continue; } /* We found a suitable memory range */ break; } while (1); /* If we are here, we found a suitable memory range */ kbuf->mem = temp_start; /* Success, stop navigating through remaining System RAM ranges */ return 1; }

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Dave Young123100.00%1100.00%
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static int locate_mem_hole_callback(struct resource *res, void *arg) { struct kexec_buf *kbuf = (struct kexec_buf *)arg; u64 start = res->start, end = res->end; unsigned long sz = end - start + 1; /* Returning 0 will take to next memory range */ if (sz < kbuf->memsz) return 0; if (end < kbuf->buf_min || start > kbuf->buf_max) return 0; /* * Allocate memory top down with-in ram range. Otherwise bottom up * allocation. */ if (kbuf->top_down) return locate_mem_hole_top_down(start, end, kbuf); return locate_mem_hole_bottom_up(start, end, kbuf); }

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Dave Young8983.96%150.00%
Tom Lendacky1716.04%150.00%
Total106100.00%2100.00%

/** * arch_kexec_walk_mem - call func(data) on free memory regions * @kbuf: Context info for the search. Also passed to @func. * @func: Function to call for each memory region. * * Return: The memory walk will stop when func returns a non-zero value * and that value will be returned. If all free regions are visited without * func returning non-zero, then zero will be returned. */
int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf, int (*func)(struct resource *, void *)) { if (kbuf->image->type == KEXEC_TYPE_CRASH) return walk_iomem_res_desc(crashk_res.desc, IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, crashk_res.start, crashk_res.end, kbuf, func); else return walk_system_ram_res(0, ULONG_MAX, kbuf, func); }

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Thiago Jung Bauermann6995.83%150.00%
Tom Lendacky34.17%150.00%
Total72100.00%2100.00%

/** * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel * @kbuf: Parameters for the memory search. * * On success, kbuf->mem will have the start address of the memory region found. * * Return: 0 on success, negative errno on error. */
int kexec_locate_mem_hole(struct kexec_buf *kbuf) { int ret; ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback); return ret == 1 ? 0 : -EADDRNOTAVAIL; }

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Thiago Jung Bauermann32100.00%1100.00%
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/** * kexec_add_buffer - place a buffer in a kexec segment * @kbuf: Buffer contents and memory parameters. * * This function assumes that kexec_mutex is held. * On successful return, @kbuf->mem will have the physical address of * the buffer in memory. * * Return: 0 on success, negative errno on error. */
int kexec_add_buffer(struct kexec_buf *kbuf) { struct kexec_segment *ksegment; int ret; /* Currently adding segment this way is allowed only in file mode */ if (!kbuf->image->file_mode) return -EINVAL; if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) return -EINVAL; /* * Make sure we are not trying to add buffer after allocating * control pages. All segments need to be placed first before * any control pages are allocated. As control page allocation * logic goes through list of segments to make sure there are * no destination overlaps. */ if (!list_empty(&kbuf->image->control_pages)) { WARN_ON(1); return -EINVAL; } /* Ensure minimum alignment needed for segments. */ kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); /* Walk the RAM ranges and allocate a suitable range for the buffer */ ret = kexec_locate_mem_hole(kbuf); if (ret) return ret; /* Found a suitable memory range */ ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; ksegment->kbuf = kbuf->buffer; ksegment->bufsz = kbuf->bufsz; ksegment->mem = kbuf->mem; ksegment->memsz = kbuf->memsz; kbuf->image->nr_segments++; return 0; }

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Dave Young15187.79%133.33%
Thiago Jung Bauermann2112.21%266.67%
Total172100.00%3100.00%

/* Calculate and store the digest of segments */
static int kexec_calculate_store_digests(struct kimage *image) { struct crypto_shash *tfm; struct shash_desc *desc; int ret = 0, i, j, zero_buf_sz, sha_region_sz; size_t desc_size, nullsz; char *digest; void *zero_buf; struct kexec_sha_region *sha_regions; struct purgatory_info *pi = &image->purgatory_info; if (!IS_ENABLED(CONFIG_ARCH_HAS_KEXEC_PURGATORY)) return 0; zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); zero_buf_sz = PAGE_SIZE; tfm = crypto_alloc_shash("sha256", 0, 0); if (IS_ERR(tfm)) { ret = PTR_ERR(tfm); goto out; } desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); desc = kzalloc(desc_size, GFP_KERNEL); if (!desc) { ret = -ENOMEM; goto out_free_tfm; } sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); sha_regions = vzalloc(sha_region_sz); if (!sha_regions) goto out_free_desc; desc->tfm = tfm; desc->flags = 0; ret = crypto_shash_init(desc); if (ret < 0) goto out_free_sha_regions; digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); if (!digest) { ret = -ENOMEM; goto out_free_sha_regions; } for (j = i = 0; i < image->nr_segments; i++) { struct kexec_segment *ksegment; ksegment = &image->segment[i]; /* * Skip purgatory as it will be modified once we put digest * info in purgatory. */ if (ksegment->kbuf == pi->purgatory_buf) continue; ret = crypto_shash_update(desc, ksegment->kbuf, ksegment->bufsz); if (ret) break; /* * Assume rest of the buffer is filled with zero and * update digest accordingly. */ nullsz = ksegment->memsz - ksegment->bufsz; while (nullsz) { unsigned long bytes = nullsz; if (bytes > zero_buf_sz) bytes = zero_buf_sz; ret = crypto_shash_update(desc, zero_buf, bytes); if (ret) break; nullsz -= bytes; } if (ret) break; sha_regions[j].start = ksegment->mem; sha_regions[j].len = ksegment->memsz; j++; } if (!ret) { ret = crypto_shash_final(desc, digest); if (ret) goto out_free_digest; ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", sha_regions, sha_region_sz, 0); if (ret) goto out_free_digest; ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", digest, SHA256_DIGEST_SIZE, 0); if (ret) goto out_free_digest; } out_free_digest: kfree(digest); out_free_sha_regions: vfree(sha_regions); out_free_desc: kfree(desc); out_free_tfm: kfree(tfm); out: return ret; }

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Dave Young47297.32%133.33%
AKASHI Takahiro112.27%133.33%
Thomas Gleixner20.41%133.33%
Total485100.00%3100.00%

#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY /* * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. * @pi: Purgatory to be loaded. * @kbuf: Buffer to setup. * * Allocates the memory needed for the buffer. Caller is responsible to free * the memory after use. * * Return: 0 on success, negative errno on error. */
static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, struct kexec_buf *kbuf) { const Elf_Shdr *sechdrs; unsigned long bss_align; unsigned long bss_sz; unsigned long align; int i, ret; sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; kbuf->buf_align = bss_align = 1; kbuf->bufsz = bss_sz = 0; for (i = 0; i < pi->ehdr->e_shnum; i++) { if (!(sechdrs[i].sh_flags & SHF_ALLOC)) continue; align = sechdrs[i].sh_addralign; if (sechdrs[i].sh_type != SHT_NOBITS) { if (kbuf->buf_align < align) kbuf->buf_align = align; kbuf->bufsz = ALIGN(kbuf->bufsz, align); kbuf->bufsz += sechdrs[i].sh_size; } else { if (bss_align < align) bss_align = align; bss_sz = ALIGN(bss_sz, align); bss_sz += sechdrs[i].sh_size; } } kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); kbuf->memsz = kbuf->bufsz + bss_sz; if (kbuf->buf_align < bss_align) kbuf->buf_align = bss_align; kbuf->buffer = vzalloc(kbuf->bufsz); if (!kbuf->buffer) return -ENOMEM; pi->purgatory_buf = kbuf->buffer; ret = kexec_add_buffer(kbuf); if (ret) goto out; return 0; out: vfree(pi->purgatory_buf); pi->purgatory_buf = NULL; return ret; }

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Philipp Rudo19565.66%266.67%
Dave Young10234.34%133.33%
Total297100.00%3100.00%

/* * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. * @pi: Purgatory to be loaded. * @kbuf: Buffer prepared to store purgatory. * * Allocates the memory needed for the buffer. Caller is responsible to free * the memory after use. * * Return: 0 on success, negative errno on error. */
static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, struct kexec_buf *kbuf) { unsigned long bss_addr; unsigned long offset; Elf_Shdr *sechdrs; int i; /* * The section headers in kexec_purgatory are read-only. In order to * have them modifiable make a temporary copy. */ sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr)); if (!sechdrs) return -ENOMEM; memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, pi->ehdr->e_shnum * sizeof(Elf_Shdr)); pi->sechdrs = sechdrs; offset = 0; bss_addr = kbuf->mem + kbuf->bufsz; kbuf->image->start = pi->ehdr->e_entry; for (i = 0; i < pi->ehdr->e_shnum; i++) { unsigned long align; void *src, *dst; if (!(sechdrs[i].sh_flags & SHF_ALLOC)) continue; align = sechdrs[i].sh_addralign; if (sechdrs[i].sh_type == SHT_NOBITS) { bss_addr = ALIGN(bss_addr, align); sechdrs[i].sh_addr = bss_addr; bss_addr += sechdrs[i].sh_size; continue; } offset = ALIGN(offset, align); if (sechdrs[i].sh_flags & SHF_EXECINSTR && pi->ehdr->e_entry >= sechdrs[i].sh_addr && pi->ehdr->e_entry < (sechdrs[i].sh_addr + sechdrs[i].sh_size)) { kbuf->image->start -= sechdrs[i].sh_addr; kbuf->image->start += kbuf->mem + offset; } src = (void *)pi->ehdr + sechdrs[i].sh_offset; dst = pi->purgatory_buf + offset; memcpy(dst, src, sechdrs[i].sh_size); sechdrs[i].sh_addr = kbuf->mem + offset; sechdrs[i].sh_offset = offset; offset += sechdrs[i].sh_size; } return 0; }

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Philipp Rudo24165.31%466.67%
Dave Young12634.15%116.67%
Thiago Jung Bauermann20.54%116.67%
Total369100.00%6100.00%


static int kexec_apply_relocations(struct kimage *image) { int i, ret; struct purgatory_info *pi = &image->purgatory_info; const Elf_Shdr *sechdrs; sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; for (i = 0; i < pi->ehdr->e_shnum; i++) { const Elf_Shdr *relsec; const Elf_Shdr *symtab; Elf_Shdr *section; relsec = sechdrs + i; if (relsec->sh_type != SHT_RELA && relsec->sh_type != SHT_REL) continue; /* * For section of type SHT_RELA/SHT_REL, * ->sh_link contains section header index of associated * symbol table. And ->sh_info contains section header * index of section to which relocations apply. */ if (relsec->sh_info >= pi->ehdr->e_shnum || relsec->sh_link >= pi->ehdr->e_shnum) return -ENOEXEC; section = pi->sechdrs + relsec->sh_info; symtab = sechdrs + relsec->sh_link; if (!(section->sh_flags & SHF_ALLOC)) continue; /* * symtab->sh_link contain section header index of associated * string table. */ if (symtab->sh_link >= pi->ehdr->e_shnum) /* Invalid section number? */ continue; /* * Respective architecture needs to provide support for applying * relocations of type SHT_RELA/SHT_REL. */ if (relsec->sh_type == SHT_RELA) ret = arch_kexec_apply_relocations_add(pi, section, relsec, symtab); else if (relsec->sh_type == SHT_REL) ret = arch_kexec_apply_relocations(pi, section, relsec, symtab); if (ret) return ret; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Young16874.01%150.00%
Philipp Rudo5925.99%150.00%
Total227100.00%2100.00%

/* * kexec_load_purgatory - Load and relocate the purgatory object. * @image: Image to add the purgatory to. * @kbuf: Memory parameters to use. * * Allocates the memory needed for image->purgatory_info.sechdrs and * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible * to free the memory after use. * * Return: 0 on success, negative errno on error. */
int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) { struct purgatory_info *pi = &image->purgatory_info; int ret; if (kexec_purgatory_size <= 0) return -EINVAL; pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; ret = kexec_purgatory_setup_kbuf(pi, kbuf); if (ret) return ret; ret = kexec_purgatory_setup_sechdrs(pi, kbuf); if (ret) goto out_free_kbuf; ret = kexec_apply_relocations(image); if (ret) goto out; return 0; out: vfree(pi->sechdrs); pi->sechdrs = NULL; out_free_kbuf: vfree(pi->purgatory_buf); pi->purgatory_buf = NULL; return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Young9471.76%120.00%
Philipp Rudo2519.08%360.00%
Thiago Jung Bauermann129.16%120.00%
Total131100.00%5100.00%

/* * kexec_purgatory_find_symbol - find a symbol in the purgatory * @pi: Purgatory to search in. * @name: Name of the symbol. * * Return: pointer to symbol in read-only symtab on success, NULL on error. */
static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, const char *name) { const Elf_Shdr *sechdrs; const Elf_Ehdr *ehdr; const Elf_Sym *syms; const char *strtab; int i, k; if (!pi->ehdr) return NULL; ehdr = pi->ehdr; sechdrs = (void *)ehdr + ehdr->e_shoff; for (i = 0; i < ehdr->e_shnum; i++) { if (sechdrs[i].sh_type != SHT_SYMTAB) continue; if (sechdrs[i].sh_link >= ehdr->e_shnum) /* Invalid strtab section number */ continue; strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; syms = (void *)ehdr + sechdrs[i].sh_offset; /* Go through symbols for a match */ for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) continue; if (strcmp(strtab + syms[k].st_name, name) != 0) continue; if (syms[k].st_shndx == SHN_UNDEF || syms[k].st_shndx >= ehdr->e_shnum) { pr_debug("Symbol: %s has bad section index %d.\n", name, syms[k].st_shndx); return NULL; } /* Found the symbol we are looking for */ return &syms[k]; } } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Young23087.79%133.33%
Philipp Rudo3212.21%266.67%
Total262100.00%3100.00%


void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) { struct purgatory_info *pi = &image->purgatory_info; const Elf_Sym *sym; Elf_Shdr *sechdr; sym = kexec_purgatory_find_symbol(pi, name); if (!sym) return ERR_PTR(-EINVAL); sechdr = &pi->sechdrs[sym->st_shndx]; /* * Returns the address where symbol will finally be loaded after * kexec_load_segment() */ return (void *)(sechdr->sh_addr + sym->st_value); }

Contributors

PersonTokensPropCommitsCommitProp
Dave Young8398.81%150.00%
Philipp Rudo11.19%150.00%
Total84100.00%2100.00%

/* * Get or set value of a symbol. If "get_value" is true, symbol value is * returned in buf otherwise symbol value is set based on value in buf. */
int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, void *buf, unsigned int size, bool get_value) { struct purgatory_info *pi = &image->purgatory_info; const Elf_Sym *sym; Elf_Shdr *sec; char *sym_buf; sym = kexec_purgatory_find_symbol(pi, name); if (!sym) return -EINVAL; if (sym->st_size != size) { pr_err("symbol %s size mismatch: expected %lu actual %u\n", name, (unsigned long)sym->st_size, size); return -EINVAL; } sec = pi->sechdrs + sym->st_shndx; if (sec->sh_type == SHT_NOBITS) { pr_err("symbol %s is in a bss section. Cannot %s\n", name, get_value ? "get" : "set"); return -EINVAL; } sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; if (get_value) memcpy((void *)buf, sym_buf, size); else memcpy((void *)sym_buf, buf, size); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Young16789.30%133.33%
Philipp Rudo2010.70%266.67%
Total187100.00%3100.00%

#endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mstart, unsigned long long mend) { int i, j; unsigned long long start, end; struct crash_mem_range temp_range = {0, 0}; for (i = 0; i < mem->nr_ranges; i++) { start = mem->ranges[i].start; end = mem->ranges[i].end; if (mstart > end || mend < start) continue; /* Truncate any area outside of range */ if (mstart < start) mstart = start; if (mend > end) mend = end; /* Found completely overlapping range */ if (mstart == start && mend == end) { mem->ranges[i].start = 0; mem->ranges[i].end = 0; if (i < mem->nr_ranges - 1) { /* Shift rest of the ranges to left */ for (j = i; j < mem->nr_ranges - 1; j++) { mem->ranges[j].start = mem->ranges[j+1].start; mem->ranges[j].end = mem->ranges[j+1].end; } } mem->nr_ranges--; return 0; } if (mstart > start && mend < end) { /* Split original range */ mem->ranges[i].end = mstart - 1; temp_range.start = mend + 1; temp_range.end = end; } else if (mstart != start) mem->ranges[i].end = mstart - 1; else mem->ranges[i].start = mend + 1; break; } /* If a split happened, add the split to array */ if (!temp_range.end) return 0; /* Split happened */ if (i == mem->max_nr_ranges - 1) return -ENOMEM; /* Location where new range should go */ j = i + 1; if (j < mem->nr_ranges) { /* Move over all ranges one slot towards the end */ for (i = mem->nr_ranges - 1; i >= j; i--) mem->ranges[i + 1] = mem->ranges[i]; } mem->ranges[j].start = temp_range.start; mem->ranges[j].end = temp_range.end; mem->nr_ranges++; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
AKASHI Takahiro414100.00%1100.00%
Total414100.00%1100.00%


int crash_prepare_elf64_headers(struct crash_mem *mem, int kernel_map, void **addr, unsigned long *sz) { Elf64_Ehdr *ehdr; Elf64_Phdr *phdr; unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; unsigned char *buf; unsigned int cpu, i; unsigned long long notes_addr; unsigned long mstart, mend; /* extra phdr for vmcoreinfo elf note */ nr_phdr = nr_cpus + 1; nr_phdr += mem->nr_ranges; /* * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64). * I think this is required by tools like gdb. So same physical * memory will be mapped in two elf headers. One will contain kernel * text virtual addresses and other will have __va(physical) addresses. */ nr_phdr++; elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr); elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN); buf = vzalloc(elf_sz); if (!buf) return -ENOMEM; ehdr = (Elf64_Ehdr *)buf; phdr = (Elf64_Phdr *)(ehdr + 1); memcpy(ehdr->e_ident, ELFMAG, SELFMAG); ehdr->e_ident[EI_CLASS] = ELFCLASS64; ehdr->e_ident[EI_DATA] = ELFDATA2LSB; ehdr->e_ident[EI_VERSION] = EV_CURRENT; ehdr->e_ident[EI_OSABI] = ELF_OSABI; memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD); ehdr->e_type = ET_CORE; ehdr->e_machine = ELF_ARCH; ehdr->e_version = EV_CURRENT; ehdr->e_phoff = sizeof(Elf64_Ehdr); ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); /* Prepare one phdr of type PT_NOTE for each present cpu */ for_each_present_cpu(cpu) { phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); phdr->p_offset = phdr->p_paddr = notes_addr; phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); (ehdr->e_phnum)++; phdr++; } /* Prepare one PT_NOTE header for vmcoreinfo */ phdr->p_type = PT_NOTE; phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note(); phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE; (ehdr->e_phnum)++; phdr++; /* Prepare PT_LOAD type program header for kernel text region */ if (kernel_map) { phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_vaddr = (Elf64_Addr)_text; phdr->p_filesz = phdr->p_memsz = _end - _text; phdr->p_offset = phdr->p_paddr = __pa_symbol(_text); ehdr->e_phnum++; phdr++; } /* Go through all the ranges in mem->ranges[] and prepare phdr */ for (i = 0; i < mem->nr_ranges; i++) { mstart = mem->ranges[i].start; mend = mem->ranges[i].end; phdr->p_type = PT_LOAD; phdr->p_flags = PF_R|PF_W|PF_X; phdr->p_offset = mstart; phdr->p_paddr = mstart; phdr->p_vaddr = (unsigned long long) __va(mstart); phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; phdr->p_align = 0; ehdr->e_phnum++; phdr++; pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n", phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, ehdr->e_phnum, phdr->p_offset); } *addr = buf; *sz = elf_sz; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
AKASHI Takahiro558100.00%1100.00%
Total558100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Dave Young301358.45%14.00%
AKASHI Takahiro127924.81%312.00%
Philipp Rudo60311.70%832.00%
Thiago Jung Bauermann1392.70%416.00%
Xunlei Pang420.81%312.00%
Mimi Zohar390.76%28.00%
Tom Lendacky200.39%14.00%
Al Viro110.21%14.00%
Minfei Huang70.14%14.00%
Thomas Gleixner20.04%14.00%
Total5155100.00%25100.00%
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