proc/kcore: clean up ELF header generation (37e949bd) · Commits · 戴 / test

fs/proc/kcore.c

+141 −209

Original line number	Diff line number	Diff line
		@@ -49,15 +49,6 @@ static struct proc_dir_entry *proc_root_kcore;
		#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
		#endif

		/* An ELF note in memory */
		struct memelfnote
		{
		const char *name;
		int type;
		unsigned int datasz;
		void *data;
		};

		static LIST_HEAD(kclist_head);
		static DECLARE_RWSEM(kclist_lock);
		static int kcore_need_update = 1;
		@@ -73,7 +64,8 @@ void __init kclist_add(struct kcore_list new, void addr, size_t size,
		list_add_tail(&new->list, &kclist_head);
		}

		static size_t get_kcore_size(int nphdr, size_t elf_buflen)
		static size_t get_kcore_size(int nphdr, size_t phdrs_len, size_t *notes_len,
		size_t *data_offset)
		{
		size_t try, size;
		struct kcore_list *m;
		@@ -87,15 +79,15 @@ static size_t get_kcore_size(int nphdr, size_t elf_buflen)
		size = try;
		nphdr = nphdr + 1;
		}
		*elf_buflen = sizeof(struct elfhdr) +
		(nphdr + 2)sizeof(struct elf_phdr) +
		3 * ((sizeof(struct elf_note)) +
		roundup(sizeof(CORE_STR), 4)) +
		roundup(sizeof(struct elf_prstatus), 4) +
		roundup(sizeof(struct elf_prpsinfo), 4) +
		roundup(arch_task_struct_size, 4);
		elf_buflen = PAGE_ALIGN(elf_buflen);
		return size + *elf_buflen;

		phdrs_len = nphdr * sizeof(struct elf_phdr);
		notes_len = (3 (sizeof(struct elf_note) + ALIGN(sizeof(CORE_STR), 4)) +
		ALIGN(sizeof(struct elf_prstatus), 4) +
		ALIGN(sizeof(struct elf_prpsinfo), 4) +
		ALIGN(arch_task_struct_size, 4));
		data_offset = PAGE_ALIGN(sizeof(struct elfhdr) + phdrs_len +
		*notes_len);
		return *data_offset + size;
		}

		#ifdef CONFIG_HIGHMEM
		@@ -241,7 +233,7 @@ static int kcore_update_ram(void)
		LIST_HEAD(list);
		LIST_HEAD(garbage);
		int nphdr;
		size_t size;
		size_t phdrs_len, notes_len, data_offset;
		struct kcore_list tmp, pos;
		int ret = 0;

		@@ -263,7 +255,8 @@ static int kcore_update_ram(void)
		}
		list_splice_tail(&list, &kclist_head);

		proc_root_kcore->size = get_kcore_size(&nphdr, &size);
		proc_root_kcore->size = get_kcore_size(&nphdr, &phdrs_len, &notes_len,
		&data_offset);

		out:
		up_write(&kclist_lock);
		@@ -274,108 +267,94 @@ out:
		return ret;
		}

		/*****************************************************************************/
		/*
		* determine size of ELF note
		*/
		static int notesize(struct memelfnote *en)
		static void append_kcore_note(char notes, size_t i, const char *name,
		unsigned int type, const void *desc,
		size_t descsz)
		{
		int sz;

		sz = sizeof(struct elf_note);
		sz += roundup((strlen(en->name) + 1), 4);
		sz += roundup(en->datasz, 4);
		struct elf_note note = (struct elf_note )&notes[*i];

		return sz;
		} /* end notesize() */
		note->n_namesz = strlen(name) + 1;
		note->n_descsz = descsz;
		note->n_type = type;
		i += sizeof(note);
		memcpy(&notes[*i], name, note->n_namesz);
		i = ALIGN(i + note->n_namesz, 4);
		memcpy(&notes[*i], desc, descsz);
		i = ALIGN(i + descsz, 4);
		}

		/*****************************************************************************/
		/*
		* store a note in the header buffer
		*/
		static char storenote(struct memelfnote men, char *bufp)
		static ssize_t
		read_kcore(struct file file, char __user buffer, size_t buflen, loff_t *fpos)
		{
		struct elf_note en;
		char *buf = file->private_data;
		size_t phdrs_offset, notes_offset, data_offset;
		size_t phdrs_len, notes_len;
		struct kcore_list *m;
		size_t tsz;
		int nphdr;
		unsigned long start;
		size_t orig_buflen = buflen;
		int ret = 0;

		#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
		down_read(&kclist_lock);

		en.n_namesz = strlen(men->name) + 1;
		en.n_descsz = men->datasz;
		en.n_type = men->type;
		get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);
		phdrs_offset = sizeof(struct elfhdr);
		notes_offset = phdrs_offset + phdrs_len;

		/* ELF file header. */
		if (buflen && *fpos < sizeof(struct elfhdr)) {
		struct elfhdr ehdr = {
		.e_ident = {
		[EI_MAG0] = ELFMAG0,
		[EI_MAG1] = ELFMAG1,
		[EI_MAG2] = ELFMAG2,
		[EI_MAG3] = ELFMAG3,
		[EI_CLASS] = ELF_CLASS,
		[EI_DATA] = ELF_DATA,
		[EI_VERSION] = EV_CURRENT,
		[EI_OSABI] = ELF_OSABI,
		},
		.e_type = ET_CORE,
		.e_machine = ELF_ARCH,
		.e_version = EV_CURRENT,
		.e_phoff = sizeof(struct elfhdr),
		.e_flags = ELF_CORE_EFLAGS,
		.e_ehsize = sizeof(struct elfhdr),
		.e_phentsize = sizeof(struct elf_phdr),
		.e_phnum = nphdr,
		};

		DUMP_WRITE(&en, sizeof(en));
		DUMP_WRITE(men->name, en.n_namesz);
		tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);
		if (copy_to_user(buffer, (char )&ehdr + fpos, tsz)) {
		ret = -EFAULT;
		goto out;
		}

		/* XXX - cast from long long to long to avoid need for libgcc.a */
		bufp = (char*) roundup((unsigned long)bufp,4);
		DUMP_WRITE(men->data, men->datasz);
		bufp = (char*) roundup((unsigned long)bufp,4);
		buffer += tsz;
		buflen -= tsz;
		*fpos += tsz;
		}

		#undef DUMP_WRITE
		/* ELF program headers. */
		if (buflen && *fpos < phdrs_offset + phdrs_len) {
		struct elf_phdr phdrs, phdr;

		return bufp;
		} /* end storenote() */
		phdrs = kzalloc(phdrs_len, GFP_KERNEL);
		if (!phdrs) {
		ret = -ENOMEM;
		goto out;
		}

		/*
		* store an ELF coredump header in the supplied buffer
		* nphdr is the number of elf_phdr to insert
		*/
		static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
		{
		struct elf_prstatus prstatus; /* NT_PRSTATUS */
		struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
		struct elf_phdr nhdr, phdr;
		struct elfhdr *elf;
		struct memelfnote notes[3];
		off_t offset = 0;
		struct kcore_list *m;
		phdrs[0].p_type = PT_NOTE;
		phdrs[0].p_offset = notes_offset;
		phdrs[0].p_filesz = notes_len;

		/* setup ELF header */
		elf = (struct elfhdr *) bufp;
		bufp += sizeof(struct elfhdr);
		offset += sizeof(struct elfhdr);
		memcpy(elf->e_ident, ELFMAG, SELFMAG);
		elf->e_ident[EI_CLASS] = ELF_CLASS;
		elf->e_ident[EI_DATA] = ELF_DATA;
		elf->e_ident[EI_VERSION]= EV_CURRENT;
		elf->e_ident[EI_OSABI] = ELF_OSABI;
		memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
		elf->e_type = ET_CORE;
		elf->e_machine = ELF_ARCH;
		elf->e_version = EV_CURRENT;
		elf->e_entry = 0;
		elf->e_phoff = sizeof(struct elfhdr);
		elf->e_shoff = 0;
		elf->e_flags = ELF_CORE_EFLAGS;
		elf->e_ehsize = sizeof(struct elfhdr);
		elf->e_phentsize= sizeof(struct elf_phdr);
		elf->e_phnum = nphdr;
		elf->e_shentsize= 0;
		elf->e_shnum = 0;
		elf->e_shstrndx = 0;

		/* setup ELF PT_NOTE program header */
		nhdr = (struct elf_phdr *) bufp;
		bufp += sizeof(struct elf_phdr);
		offset += sizeof(struct elf_phdr);
		nhdr->p_type = PT_NOTE;
		nhdr->p_offset = 0;
		nhdr->p_vaddr = 0;
		nhdr->p_paddr = 0;
		nhdr->p_filesz = 0;
		nhdr->p_memsz = 0;
		nhdr->p_flags = 0;
		nhdr->p_align = 0;

		/* setup ELF PT_LOAD program header for every area */
		phdr = &phdrs[1];
		list_for_each_entry(m, &kclist_head, list) {
		phdr = (struct elf_phdr *) bufp;
		bufp += sizeof(struct elf_phdr);
		offset += sizeof(struct elf_phdr);

		phdr->p_type = PT_LOAD;
		phdr->p_flags = PF_R \| PF_W \| PF_X;
		phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
		phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
		phdr->p_vaddr = (size_t)m->addr;
		if (m->type == KCORE_RAM)
		phdr->p_paddr = __pa(m->addr);
		@@ -385,117 +364,71 @@ static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
		phdr->p_paddr = (elf_addr_t)-1;
		phdr->p_filesz = phdr->p_memsz = m->size;
		phdr->p_align = PAGE_SIZE;
		phdr++;
		}

		/*
		* Set up the notes in similar form to SVR4 core dumps made
		* with info from their /proc.
		*/
		nhdr->p_offset = offset;

		/* set up the process status */
		notes[0].name = CORE_STR;
		notes[0].type = NT_PRSTATUS;
		notes[0].datasz = sizeof(struct elf_prstatus);
		notes[0].data = &prstatus;

		memset(&prstatus, 0, sizeof(struct elf_prstatus));

		nhdr->p_filesz = notesize(&notes[0]);
		bufp = storenote(&notes[0], bufp);

		/* set up the process info */
		notes[1].name = CORE_STR;
		notes[1].type = NT_PRPSINFO;
		notes[1].datasz = sizeof(struct elf_prpsinfo);
		notes[1].data = &prpsinfo;

		memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
		prpsinfo.pr_state = 0;
		prpsinfo.pr_sname = 'R';
		prpsinfo.pr_zomb = 0;

		strcpy(prpsinfo.pr_fname, "vmlinux");
		strlcpy(prpsinfo.pr_psargs, saved_command_line, sizeof(prpsinfo.pr_psargs));

		nhdr->p_filesz += notesize(&notes[1]);
		bufp = storenote(&notes[1], bufp);

		/* set up the task structure */
		notes[2].name = CORE_STR;
		notes[2].type = NT_TASKSTRUCT;
		notes[2].datasz = arch_task_struct_size;
		notes[2].data = current;

		nhdr->p_filesz += notesize(&notes[2]);
		bufp = storenote(&notes[2], bufp);

		} /* end elf_kcore_store_hdr() */

		/*****************************************************************************/
		/*
		* read from the ELF header and then kernel memory
		*/
		static ssize_t
		read_kcore(struct file file, char __user buffer, size_t buflen, loff_t *fpos)
		{
		char *buf = file->private_data;
		size_t size, tsz;
		size_t elf_buflen;
		int nphdr;
		unsigned long start;
		size_t orig_buflen = buflen;
		int ret = 0;

		down_read(&kclist_lock);
		size = get_kcore_size(&nphdr, &elf_buflen);

		if (buflen == 0 \|\| *fpos >= size)
		tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);
		if (copy_to_user(buffer, (char )phdrs + fpos - phdrs_offset,
		tsz)) {
		kfree(phdrs);
		ret = -EFAULT;
		goto out;
		}
		kfree(phdrs);

		buffer += tsz;
		buflen -= tsz;
		*fpos += tsz;
		}

		/* trim buflen to not go beyond EOF */
		if (buflen > size - *fpos)
		buflen = size - *fpos;
		/* ELF note segment. */
		if (buflen && *fpos < notes_offset + notes_len) {
		struct elf_prstatus prstatus = {};
		struct elf_prpsinfo prpsinfo = {
		.pr_sname = 'R',
		.pr_fname = "vmlinux",
		};
		char *notes;
		size_t i = 0;

		/* construct an ELF core header if we'll need some of it */
		if (*fpos < elf_buflen) {
		char * elf_buf;
		strlcpy(prpsinfo.pr_psargs, saved_command_line,
		sizeof(prpsinfo.pr_psargs));

		tsz = elf_buflen - *fpos;
		if (buflen < tsz)
		tsz = buflen;
		elf_buf = kzalloc(elf_buflen, GFP_KERNEL);
		if (!elf_buf) {
		notes = kzalloc(notes_len, GFP_KERNEL);
		if (!notes) {
		ret = -ENOMEM;
		goto out;
		}
		elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
		if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
		kfree(elf_buf);

		append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
		sizeof(prstatus));
		append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
		sizeof(prpsinfo));
		append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
		arch_task_struct_size);

		tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos);
		if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) {
		kfree(notes);
		ret = -EFAULT;
		goto out;
		}
		kfree(elf_buf);
		kfree(notes);

		buffer += tsz;
		buflen -= tsz;
		*fpos += tsz;
		buffer += tsz;

		/* leave now if filled buffer already */
		if (buflen == 0)
		goto out;
		}

		/*
		* Check to see if our file offset matches with any of
		* the addresses in the elf_phdr on our list.
		*/
		start = kc_offset_to_vaddr(*fpos - elf_buflen);
		start = kc_offset_to_vaddr(*fpos - data_offset);
		if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
		tsz = buflen;

		while (buflen) {
		struct kcore_list *m;

		list_for_each_entry(m, &kclist_head, list) {
		if (start >= m->addr && start < (m->addr+m->size))
		break;
		@@ -557,7 +490,6 @@ out:
		return orig_buflen - buflen;
		}


		static int open_kcore(struct inode inode, struct file filp)
		{
		if (!capable(CAP_SYS_RAWIO))

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