diff options
| -rw-r--r-- | fs/binfmt_elf.c | 120 | ||||
| -rw-r--r-- | fs/binfmt_elf_fdpic.c | 83 | ||||
| -rw-r--r-- | fs/coredump.c | 101 | ||||
| -rw-r--r-- | include/linux/coredump.h | 1 |
4 files changed, 106 insertions, 199 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index cf956edf05ef..c1756fd8d10b 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1414,126 +1414,6 @@ out: * Jeremy Fitzhardinge <jeremy@sw.oz.au> */ -/* - * The purpose of always_dump_vma() is to make sure that special kernel mappings - * that are useful for post-mortem analysis are included in every core dump. - * In that way we ensure that the core dump is fully interpretable later - * without matching up the same kernel and hardware config to see what PC values - * meant. These special mappings include - vDSO, vsyscall, and other - * architecture specific mappings - */ -static bool always_dump_vma(struct vm_area_struct *vma) -{ - /* Any vsyscall mappings? */ - if (vma == get_gate_vma(vma->vm_mm)) - return true; - - /* - * Assume that all vmas with a .name op should always be dumped. - * If this changes, a new vm_ops field can easily be added. - */ - if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma)) - return true; - - /* - * arch_vma_name() returns non-NULL for special architecture mappings, - * such as vDSO sections. - */ - if (arch_vma_name(vma)) - return true; - - return false; -} - -/* - * Decide what to dump of a segment, part, all or none. - */ -static unsigned long vma_dump_size(struct vm_area_struct *vma, - unsigned long mm_flags) -{ -#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) - - /* always dump the vdso and vsyscall sections */ - if (always_dump_vma(vma)) - goto whole; - - if (vma->vm_flags & VM_DONTDUMP) - return 0; - - /* support for DAX */ - if (vma_is_dax(vma)) { - if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED)) - goto whole; - if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE)) - goto whole; - return 0; - } - - /* Hugetlb memory check */ - if (is_vm_hugetlb_page(vma)) { - if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) - goto whole; - if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) - goto whole; - return 0; - } - - /* Do not dump I/O mapped devices or special mappings */ - if (vma->vm_flags & VM_IO) - return 0; - - /* By default, dump shared memory if mapped from an anonymous file. */ - if (vma->vm_flags & VM_SHARED) { - if (file_inode(vma->vm_file)->i_nlink == 0 ? - FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) - goto whole; - return 0; - } - - /* Dump segments that have been written to. */ - if (vma->anon_vma && FILTER(ANON_PRIVATE)) - goto whole; - if (vma->vm_file == NULL) - return 0; - - if (FILTER(MAPPED_PRIVATE)) - goto whole; - - /* - * If this looks like the beginning of a DSO or executable mapping, - * check for an ELF header. If we find one, dump the first page to - * aid in determining what was mapped here. - */ - if (FILTER(ELF_HEADERS) && - vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { - u32 __user *header = (u32 __user *) vma->vm_start; - u32 word; - /* - * Doing it this way gets the constant folded by GCC. - */ - union { - u32 cmp; - char elfmag[SELFMAG]; - } magic; - BUILD_BUG_ON(SELFMAG != sizeof word); - magic.elfmag[EI_MAG0] = ELFMAG0; - magic.elfmag[EI_MAG1] = ELFMAG1; - magic.elfmag[EI_MAG2] = ELFMAG2; - magic.elfmag[EI_MAG3] = ELFMAG3; - if (unlikely(get_user(word, header))) - word = 0; - if (word == magic.cmp) - return PAGE_SIZE; - } - -#undef FILTER - - return 0; - -whole: - return vma->vm_end - vma->vm_start; -} - /* An ELF note in memory */ struct memelfnote { diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 76e8c0defdc8..f531c6198864 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1215,76 +1215,6 @@ struct elf_prstatus_fdpic int pr_fpvalid; /* True if math co-processor being used. */ }; -/* - * 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, unsigned long mm_flags) -{ - int dump_ok; - - /* Do not dump I/O mapped devices or special mappings */ - if (vma->vm_flags & VM_IO) { - 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; - } - - /* support for DAX */ - if (vma_is_dax(vma)) { - if (vma->vm_flags & VM_SHARED) { - dump_ok = test_bit(MMF_DUMP_DAX_SHARED, &mm_flags); - kdcore("%08lx: %08lx: %s (DAX shared)", vma->vm_start, - vma->vm_flags, dump_ok ? "yes" : "no"); - } else { - dump_ok = test_bit(MMF_DUMP_DAX_PRIVATE, &mm_flags); - kdcore("%08lx: %08lx: %s (DAX private)", vma->vm_start, - vma->vm_flags, dump_ok ? "yes" : "no"); - } - return dump_ok; - } - - /* By default, dump shared memory if mapped from an anonymous file. */ - if (vma->vm_flags & VM_SHARED) { - if (file_inode(vma->vm_file)->i_nlink == 0) { - dump_ok = test_bit(MMF_DUMP_ANON_SHARED, &mm_flags); - kdcore("%08lx: %08lx: %s (share)", vma->vm_start, - vma->vm_flags, dump_ok ? "yes" : "no"); - return dump_ok; - } - - dump_ok = test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags); - kdcore("%08lx: %08lx: %s (share)", vma->vm_start, - vma->vm_flags, dump_ok ? "yes" : "no"); - return dump_ok; - } - -#ifdef CONFIG_MMU - /* By default, if it hasn't been written to, don't write it out */ - if (!vma->anon_vma) { - dump_ok = test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags); - kdcore("%08lx: %08lx: %s (!anon)", vma->vm_start, - vma->vm_flags, dump_ok ? "yes" : "no"); - return dump_ok; - } -#endif - - dump_ok = test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags); - kdcore("%08lx: %08lx: %s", vma->vm_start, vma->vm_flags, - dump_ok ? "yes" : "no"); - return dump_ok; -} - /* An ELF note in memory */ struct memelfnote { @@ -1529,13 +1459,9 @@ static bool elf_fdpic_dump_segments(struct coredump_params *cprm) struct vm_area_struct *vma; for (vma = current->mm->mmap; vma; vma = vma->vm_next) { - unsigned long addr; - - if (!maydump(vma, cprm->mm_flags)) - continue; + unsigned long size = vma_dump_size(vma, cprm->mm_flags); - if (!dump_user_range(cprm, vma->vm_start, - vma->vma_end - vma->vm_start)) + if (!dump_user_range(cprm, vma->vm_start, size)) return false; } return true; @@ -1547,8 +1473,7 @@ static size_t elf_core_vma_data_size(unsigned long mm_flags) size_t size = 0; for (vma = current->mm->mmap; vma; vma = vma->vm_next) - if (maydump(vma, mm_flags)) - size += vma->vm_end - vma->vm_start; + size += vma_dump_size(vma, mm_flags); return size; } @@ -1694,7 +1619,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm) phdr.p_offset = offset; phdr.p_vaddr = vma->vm_start; phdr.p_paddr = 0; - phdr.p_filesz = maydump(vma, cprm->mm_flags) ? sz : 0; + phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags); phdr.p_memsz = sz; offset += phdr.p_filesz; phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0; diff --git a/fs/coredump.c b/fs/coredump.c index 6042d15acd51..4ef4c49a65b7 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -936,3 +936,104 @@ void dump_truncate(struct coredump_params *cprm) } } EXPORT_SYMBOL(dump_truncate); + +/* + * The purpose of always_dump_vma() is to make sure that special kernel mappings + * that are useful for post-mortem analysis are included in every core dump. + * In that way we ensure that the core dump is fully interpretable later + * without matching up the same kernel and hardware config to see what PC values + * meant. These special mappings include - vDSO, vsyscall, and other + * architecture specific mappings + */ +static bool always_dump_vma(struct vm_area_struct *vma) +{ + /* Any vsyscall mappings? */ + if (vma == get_gate_vma(vma->vm_mm)) + return true; + + /* + * Assume that all vmas with a .name op should always be dumped. + * If this changes, a new vm_ops field can easily be added. + */ + if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma)) + return true; + + /* + * arch_vma_name() returns non-NULL for special architecture mappings, + * such as vDSO sections. + */ + if (arch_vma_name(vma)) + return true; + + return false; +} + +/* + * Decide how much of @vma's contents should be included in a core dump. + */ +unsigned long vma_dump_size(struct vm_area_struct *vma, unsigned long mm_flags) +{ +#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) + + /* always dump the vdso and vsyscall sections */ + if (always_dump_vma(vma)) + goto whole; + + if (vma->vm_flags & VM_DONTDUMP) + return 0; + + /* support for DAX */ + if (vma_is_dax(vma)) { + if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED)) + goto whole; + if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE)) + goto whole; + return 0; + } + + /* Hugetlb memory check */ + if (is_vm_hugetlb_page(vma)) { + if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) + goto whole; + if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) + goto whole; + return 0; + } + + /* Do not dump I/O mapped devices or special mappings */ + if (vma->vm_flags & VM_IO) + return 0; + + /* By default, dump shared memory if mapped from an anonymous file. */ + if (vma->vm_flags & VM_SHARED) { + if (file_inode(vma->vm_file)->i_nlink == 0 ? + FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) + goto whole; + return 0; + } + + /* Dump segments that have been written to. */ + if ((!IS_ENABLED(CONFIG_MMU) || vma->anon_vma) && FILTER(ANON_PRIVATE)) + goto whole; + if (vma->vm_file == NULL) + return 0; + + if (FILTER(MAPPED_PRIVATE)) + goto whole; + + /* + * If this is the beginning of an executable file mapping, + * dump the first page to aid in determining what was mapped here. + */ + if (FILTER(ELF_HEADERS) && + vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ) && + (READ_ONCE(file_inode(vma->vm_file)->i_mode) & 0111) != 0) + return PAGE_SIZE; + +#undef FILTER + + return 0; + +whole: + return vma->vm_end - vma->vm_start; +} diff --git a/include/linux/coredump.h b/include/linux/coredump.h index f0b71a74d0bc..bfecb8d79a7f 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -16,6 +16,7 @@ extern int dump_skip(struct coredump_params *cprm, size_t nr); extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr); extern int dump_align(struct coredump_params *cprm, int align); extern void dump_truncate(struct coredump_params *cprm); +unsigned long vma_dump_size(struct vm_area_struct *vma, unsigned long mm_flags); int dump_user_range(struct coredump_params *cprm, unsigned long start, unsigned long len); #ifdef CONFIG_COREDUMP |