From 6d8c4e3b0150ff537902477ed62f8a8e9e70007b Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 10 Jul 2006 04:44:55 -0700 Subject: [PATCH] FDPIC: Add coredump capability for the ELF-FDPIC binfmt Add coredump capability for the ELF-FDPIC binfmt. Signed-off-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/binfmt_elf_fdpic.c | 676 +++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 674 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index a4ff873..2f33658 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -24,7 +24,9 @@ #include #include #include +#include #include +#include #include #include #include @@ -48,6 +50,12 @@ typedef char *elf_caddr_t; #define kdebug(fmt, ...) do {} while(0) #endif +#if 0 +#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ ) +#else +#define kdcore(fmt, ...) do {} while(0) +#endif + MODULE_LICENSE("GPL"); static int load_elf_fdpic_binary(struct linux_binprm *, struct pt_regs *); @@ -70,10 +78,16 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *, static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *, struct file *, struct mm_struct *); +#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE) +static int elf_fdpic_core_dump(long, struct pt_regs *, struct file *); +#endif + static struct linux_binfmt elf_fdpic_format = { .module = THIS_MODULE, .load_binary = load_elf_fdpic_binary, -// .core_dump = elf_fdpic_core_dump, +#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE) + .core_dump = elf_fdpic_core_dump, +#endif .min_coredump = ELF_EXEC_PAGESIZE, }; @@ -87,7 +101,7 @@ static void __exit exit_elf_fdpic_binfmt(void) unregister_binfmt(&elf_fdpic_format); } -module_init(init_elf_fdpic_binfmt); +core_initcall(init_elf_fdpic_binfmt); module_exit(exit_elf_fdpic_binfmt); static int is_elf_fdpic(struct elfhdr *hdr, struct file *file) @@ -1118,3 +1132,661 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params, return 0; } + +/*****************************************************************************/ +/* + * ELF-FDPIC core dumper + * + * Modelled on fs/exec.c:aout_core_dump() + * Jeremy Fitzhardinge + * + * Modelled on fs/binfmt_elf.c core dumper + */ +#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE) + +/* + * These are the only things you should do on a core-file: use only these + * functions to write out all the necessary info. + */ +static int dump_write(struct file *file, const void *addr, int nr) +{ + return file->f_op->write(file, addr, nr, &file->f_pos) == nr; +} + +static int dump_seek(struct file *file, loff_t off) +{ + if (file->f_op->llseek) { + if (file->f_op->llseek(file, off, SEEK_SET) != off) + return 0; + } else { + file->f_pos = off; + } + return 1; +} + +/* + * Decide whether a segment is worth dumping; default is yes to be + * sure (missing info is worse than too much; etc). + * Personally I'd include everything, and use the coredump limit... + * + * I think we should skip something. But I am not sure how. H.J. + */ +static int maydump(struct vm_area_struct *vma) +{ + /* Do not dump I/O mapped devices or special mappings */ + if (vma->vm_flags & (VM_IO | VM_RESERVED)) { + kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags); + return 0; + } + + /* If we may not read the contents, don't allow us to dump + * them either. "dump_write()" can't handle it anyway. + */ + if (!(vma->vm_flags & VM_READ)) { + kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags); + return 0; + } + + /* Dump shared memory only if mapped from an anonymous file. */ + if (vma->vm_flags & VM_SHARED) { + if (vma->vm_file->f_dentry->d_inode->i_nlink == 0) { + kdcore("%08lx: %08lx: no (share)", vma->vm_start, vma->vm_flags); + return 1; + } + + kdcore("%08lx: %08lx: no (share)", vma->vm_start, vma->vm_flags); + return 0; + } + +#ifdef CONFIG_MMU + /* If it hasn't been written to, don't write it out */ + if (!vma->anon_vma) { + kdcore("%08lx: %08lx: no (!anon)", vma->vm_start, vma->vm_flags); + return 0; + } +#endif + + kdcore("%08lx: %08lx: yes", vma->vm_start, vma->vm_flags); + return 1; +} + +/* An ELF note in memory */ +struct memelfnote +{ + const char *name; + int type; + unsigned int datasz; + void *data; +}; + +static int notesize(struct memelfnote *en) +{ + int sz; + + sz = sizeof(struct elf_note); + sz += roundup(strlen(en->name) + 1, 4); + sz += roundup(en->datasz, 4); + + return sz; +} + +/* #define DEBUG */ + +#define DUMP_WRITE(addr, nr) \ + do { if (!dump_write(file, (addr), (nr))) return 0; } while(0) +#define DUMP_SEEK(off) \ + do { if (!dump_seek(file, (off))) return 0; } while(0) + +static int writenote(struct memelfnote *men, struct file *file) +{ + struct elf_note en; + + en.n_namesz = strlen(men->name) + 1; + en.n_descsz = men->datasz; + en.n_type = men->type; + + DUMP_WRITE(&en, sizeof(en)); + DUMP_WRITE(men->name, en.n_namesz); + /* XXX - cast from long long to long to avoid need for libgcc.a */ + DUMP_SEEK(roundup((unsigned long)file->f_pos, 4)); /* XXX */ + DUMP_WRITE(men->data, men->datasz); + DUMP_SEEK(roundup((unsigned long)file->f_pos, 4)); /* XXX */ + + return 1; +} +#undef DUMP_WRITE +#undef DUMP_SEEK + +#define DUMP_WRITE(addr, nr) \ + if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \ + goto end_coredump; +#define DUMP_SEEK(off) \ + if (!dump_seek(file, (off))) \ + goto end_coredump; + +static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs) +{ + 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_FDPIC_CORE_EFLAGS; + elf->e_ehsize = sizeof(struct elfhdr); + elf->e_phentsize = sizeof(struct elf_phdr); + elf->e_phnum = segs; + elf->e_shentsize = 0; + elf->e_shnum = 0; + elf->e_shstrndx = 0; + return; +} + +static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset) +{ + phdr->p_type = PT_NOTE; + phdr->p_offset = offset; + phdr->p_vaddr = 0; + phdr->p_paddr = 0; + phdr->p_filesz = sz; + phdr->p_memsz = 0; + phdr->p_flags = 0; + phdr->p_align = 0; + return; +} + +static inline void fill_note(struct memelfnote *note, const char *name, int type, + unsigned int sz, void *data) +{ + note->name = name; + note->type = type; + note->datasz = sz; + note->data = data; + return; +} + +/* + * fill up all the fields in prstatus from the given task struct, except + * registers which need to be filled up seperately. + */ +static void fill_prstatus(struct elf_prstatus *prstatus, + struct task_struct *p, long signr) +{ + prstatus->pr_info.si_signo = prstatus->pr_cursig = signr; + prstatus->pr_sigpend = p->pending.signal.sig[0]; + prstatus->pr_sighold = p->blocked.sig[0]; + prstatus->pr_pid = p->pid; + prstatus->pr_ppid = p->parent->pid; + prstatus->pr_pgrp = process_group(p); + prstatus->pr_sid = p->signal->session; + if (thread_group_leader(p)) { + /* + * This is the record for the group leader. Add in the + * cumulative times of previous dead threads. This total + * won't include the time of each live thread whose state + * is included in the core dump. The final total reported + * to our parent process when it calls wait4 will include + * those sums as well as the little bit more time it takes + * this and each other thread to finish dying after the + * core dump synchronization phase. + */ + cputime_to_timeval(cputime_add(p->utime, p->signal->utime), + &prstatus->pr_utime); + cputime_to_timeval(cputime_add(p->stime, p->signal->stime), + &prstatus->pr_stime); + } else { + cputime_to_timeval(p->utime, &prstatus->pr_utime); + cputime_to_timeval(p->stime, &prstatus->pr_stime); + } + cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime); + cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime); + + prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap; + prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap; +} + +static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p, + struct mm_struct *mm) +{ + unsigned int i, len; + + /* first copy the parameters from user space */ + memset(psinfo, 0, sizeof(struct elf_prpsinfo)); + + len = mm->arg_end - mm->arg_start; + if (len >= ELF_PRARGSZ) + len = ELF_PRARGSZ - 1; + if (copy_from_user(&psinfo->pr_psargs, + (const char __user *) mm->arg_start, len)) + return -EFAULT; + for (i = 0; i < len; i++) + if (psinfo->pr_psargs[i] == 0) + psinfo->pr_psargs[i] = ' '; + psinfo->pr_psargs[len] = 0; + + psinfo->pr_pid = p->pid; + psinfo->pr_ppid = p->parent->pid; + psinfo->pr_pgrp = process_group(p); + psinfo->pr_sid = p->signal->session; + + i = p->state ? ffz(~p->state) + 1 : 0; + psinfo->pr_state = i; + psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i]; + psinfo->pr_zomb = psinfo->pr_sname == 'Z'; + psinfo->pr_nice = task_nice(p); + psinfo->pr_flag = p->flags; + SET_UID(psinfo->pr_uid, p->uid); + SET_GID(psinfo->pr_gid, p->gid); + strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); + + return 0; +} + +/* Here is the structure in which status of each thread is captured. */ +struct elf_thread_status +{ + struct list_head list; + struct elf_prstatus prstatus; /* NT_PRSTATUS */ + elf_fpregset_t fpu; /* NT_PRFPREG */ + struct task_struct *thread; +#ifdef ELF_CORE_COPY_XFPREGS + elf_fpxregset_t xfpu; /* NT_PRXFPREG */ +#endif + struct memelfnote notes[3]; + int num_notes; +}; + +/* + * In order to add the specific thread information for the elf file format, + * we need to keep a linked list of every thread's pr_status and then create + * a single section for them in the final core file. + */ +static int elf_dump_thread_status(long signr, struct elf_thread_status *t) +{ + struct task_struct *p = t->thread; + int sz = 0; + + t->num_notes = 0; + + fill_prstatus(&t->prstatus, p, signr); + elf_core_copy_task_regs(p, &t->prstatus.pr_reg); + + fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus), + &t->prstatus); + t->num_notes++; + sz += notesize(&t->notes[0]); + + t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu); + if (t->prstatus.pr_fpvalid) { + fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu), + &t->fpu); + t->num_notes++; + sz += notesize(&t->notes[1]); + } + +#ifdef ELF_CORE_COPY_XFPREGS + if (elf_core_copy_task_xfpregs(p, &t->xfpu)) { + fill_note(&t->notes[2], "LINUX", NT_PRXFPREG, sizeof(t->xfpu), + &t->xfpu); + t->num_notes++; + sz += notesize(&t->notes[2]); + } +#endif + return sz; +} + +/* + * dump the segments for an MMU process + */ +#ifdef CONFIG_MMU +static int elf_fdpic_dump_segments(struct file *file, struct mm_struct *mm, + size_t *size, unsigned long *limit) +{ + struct vm_area_struct *vma; + + for (vma = current->mm->mmap; vma; vma = vma->vm_next) { + unsigned long addr; + + if (!maydump(vma)) + continue; + + for (addr = vma->vm_start; + addr < vma->vm_end; + addr += PAGE_SIZE + ) { + struct vm_area_struct *vma; + struct page *page; + + if (get_user_pages(current, current->mm, addr, 1, 0, 1, + &page, &vma) <= 0) { + DUMP_SEEK(file->f_pos + PAGE_SIZE); + } + else if (page == ZERO_PAGE(addr)) { + DUMP_SEEK(file->f_pos + PAGE_SIZE); + page_cache_release(page); + } + else { + void *kaddr; + + flush_cache_page(vma, addr, page_to_pfn(page)); + kaddr = kmap(page); + if ((*size += PAGE_SIZE) > *limit || + !dump_write(file, kaddr, PAGE_SIZE) + ) { + kunmap(page); + page_cache_release(page); + return -EIO; + } + kunmap(page); + page_cache_release(page); + } + } + } + + return 0; + +end_coredump: + return -EFBIG; +} +#endif + +/* + * dump the segments for a NOMMU process + */ +#ifndef CONFIG_MMU +static int elf_fdpic_dump_segments(struct file *file, struct mm_struct *mm, + size_t *size, unsigned long *limit) +{ + struct vm_list_struct *vml; + + for (vml = current->mm->context.vmlist; vml; vml = vml->next) { + struct vm_area_struct *vma = vml->vma; + + if (!maydump(vma)) + continue; + + if ((*size += PAGE_SIZE) > *limit) + return -EFBIG; + + if (!dump_write(file, (void *) vma->vm_start, + vma->vm_end - vma->vm_start)) + return -EIO; + } + + return 0; +} +#endif + +/* + * Actual dumper + * + * This is a two-pass process; first we find the offsets of the bits, + * and then they are actually written out. If we run out of core limit + * we just truncate. + */ +static int elf_fdpic_core_dump(long signr, struct pt_regs *regs, + struct file *file) +{ +#define NUM_NOTES 6 + int has_dumped = 0; + mm_segment_t fs; + int segs; + size_t size = 0; + int i; + struct vm_area_struct *vma; + struct elfhdr *elf = NULL; + loff_t offset = 0, dataoff; + unsigned long limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; + int numnote; + struct memelfnote *notes = NULL; + struct elf_prstatus *prstatus = NULL; /* NT_PRSTATUS */ + struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */ + struct task_struct *g, *p; + LIST_HEAD(thread_list); + struct list_head *t; + elf_fpregset_t *fpu = NULL; +#ifdef ELF_CORE_COPY_XFPREGS + elf_fpxregset_t *xfpu = NULL; +#endif + int thread_status_size = 0; +#ifndef CONFIG_MMU + struct vm_list_struct *vml; +#endif + elf_addr_t *auxv; + + /* + * We no longer stop all VM operations. + * + * This is because those proceses that could possibly change map_count + * or the mmap / vma pages are now blocked in do_exit on current + * finishing this core dump. + * + * Only ptrace can touch these memory addresses, but it doesn't change + * the map_count or the pages allocated. So no possibility of crashing + * exists while dumping the mm->vm_next areas to the core file. + */ + + /* alloc memory for large data structures: too large to be on stack */ + elf = kmalloc(sizeof(*elf), GFP_KERNEL); + if (!elf) + goto cleanup; + prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL); + if (!prstatus) + goto cleanup; + psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL); + if (!psinfo) + goto cleanup; + notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL); + if (!notes) + goto cleanup; + fpu = kmalloc(sizeof(*fpu), GFP_KERNEL); + if (!fpu) + goto cleanup; +#ifdef ELF_CORE_COPY_XFPREGS + xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL); + if (!xfpu) + goto cleanup; +#endif + + if (signr) { + struct elf_thread_status *tmp; + read_lock(&tasklist_lock); + do_each_thread(g,p) + if (current->mm == p->mm && current != p) { + tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC); + if (!tmp) { + read_unlock(&tasklist_lock); + goto cleanup; + } + INIT_LIST_HEAD(&tmp->list); + tmp->thread = p; + list_add(&tmp->list, &thread_list); + } + while_each_thread(g,p); + read_unlock(&tasklist_lock); + list_for_each(t, &thread_list) { + struct elf_thread_status *tmp; + int sz; + + tmp = list_entry(t, struct elf_thread_status, list); + sz = elf_dump_thread_status(signr, tmp); + thread_status_size += sz; + } + } + + /* now collect the dump for the current */ + fill_prstatus(prstatus, current, signr); + elf_core_copy_regs(&prstatus->pr_reg, regs); + +#ifdef CONFIG_MMU + segs = current->mm->map_count; +#else + segs = 0; + for (vml = current->mm->context.vmlist; vml; vml = vml->next) + segs++; +#endif +#ifdef ELF_CORE_EXTRA_PHDRS + segs += ELF_CORE_EXTRA_PHDRS; +#endif + + /* Set up header */ + fill_elf_fdpic_header(elf, segs + 1); /* including notes section */ + + has_dumped = 1; + current->flags |= PF_DUMPCORE; + + /* + * Set up the notes in similar form to SVR4 core dumps made + * with info from their /proc. + */ + + fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus); + fill_psinfo(psinfo, current->group_leader, current->mm); + fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo); + + numnote = 2; + + auxv = (elf_addr_t *) current->mm->saved_auxv; + + i = 0; + do + i += 2; + while (auxv[i - 2] != AT_NULL); + fill_note(¬es[numnote++], "CORE", NT_AUXV, + i * sizeof(elf_addr_t), auxv); + + /* Try to dump the FPU. */ + if ((prstatus->pr_fpvalid = + elf_core_copy_task_fpregs(current, regs, fpu))) + fill_note(notes + numnote++, + "CORE", NT_PRFPREG, sizeof(*fpu), fpu); +#ifdef ELF_CORE_COPY_XFPREGS + if (elf_core_copy_task_xfpregs(current, xfpu)) + fill_note(notes + numnote++, + "LINUX", NT_PRXFPREG, sizeof(*xfpu), xfpu); +#endif + + fs = get_fs(); + set_fs(KERNEL_DS); + + DUMP_WRITE(elf, sizeof(*elf)); + offset += sizeof(*elf); /* Elf header */ + offset += (segs+1) * sizeof(struct elf_phdr); /* Program headers */ + + /* Write notes phdr entry */ + { + struct elf_phdr phdr; + int sz = 0; + + for (i = 0; i < numnote; i++) + sz += notesize(notes + i); + + sz += thread_status_size; + + fill_elf_note_phdr(&phdr, sz, offset); + offset += sz; + DUMP_WRITE(&phdr, sizeof(phdr)); + } + + /* Page-align dumped data */ + dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE); + + /* write program headers for segments dump */ + for ( +#ifdef CONFIG_MMU + vma = current->mm->mmap; vma; vma = vma->vm_next +#else + vml = current->mm->context.vmlist; vml; vml = vml->next +#endif + ) { + struct elf_phdr phdr; + size_t sz; + +#ifndef CONFIG_MMU + vma = vml->vma; +#endif + + sz = vma->vm_end - vma->vm_start; + + phdr.p_type = PT_LOAD; + phdr.p_offset = offset; + phdr.p_vaddr = vma->vm_start; + phdr.p_paddr = 0; + phdr.p_filesz = maydump(vma) ? sz : 0; + phdr.p_memsz = sz; + offset += phdr.p_filesz; + phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0; + if (vma->vm_flags & VM_WRITE) + phdr.p_flags |= PF_W; + if (vma->vm_flags & VM_EXEC) + phdr.p_flags |= PF_X; + phdr.p_align = ELF_EXEC_PAGESIZE; + + DUMP_WRITE(&phdr, sizeof(phdr)); + } + +#ifdef ELF_CORE_WRITE_EXTRA_PHDRS + ELF_CORE_WRITE_EXTRA_PHDRS; +#endif + + /* write out the notes section */ + for (i = 0; i < numnote; i++) + if (!writenote(notes + i, file)) + goto end_coredump; + + /* write out the thread status notes section */ + list_for_each(t, &thread_list) { + struct elf_thread_status *tmp = + list_entry(t, struct elf_thread_status, list); + + for (i = 0; i < tmp->num_notes; i++) + if (!writenote(&tmp->notes[i], file)) + goto end_coredump; + } + + DUMP_SEEK(dataoff); + + if (elf_fdpic_dump_segments(file, current->mm, &size, &limit) < 0) + goto end_coredump; + +#ifdef ELF_CORE_WRITE_EXTRA_DATA + ELF_CORE_WRITE_EXTRA_DATA; +#endif + + if (file->f_pos != offset) { + /* Sanity check */ + printk(KERN_WARNING + "elf_core_dump: file->f_pos (%lld) != offset (%lld)\n", + file->f_pos, offset); + } + +end_coredump: + set_fs(fs); + +cleanup: + while (!list_empty(&thread_list)) { + struct list_head *tmp = thread_list.next; + list_del(tmp); + kfree(list_entry(tmp, struct elf_thread_status, list)); + } + + kfree(elf); + kfree(prstatus); + kfree(psinfo); + kfree(notes); + kfree(fpu); +#ifdef ELF_CORE_COPY_XFPREGS + kfree(xfpu); +#endif + return has_dumped; +#undef NUM_NOTES +} + +#endif /* USE_ELF_CORE_DUMP */ -- cgit v1.1