diff options
| -rw-r--r-- | fs/binfmt_elf.c | 78 | ||||
| -rw-r--r-- | include/linux/sched.h | 3 |
2 files changed, 55 insertions, 26 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 66cd711a6b1..4263326ede0 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1201,35 +1201,68 @@ static int dump_seek(struct file *file, loff_t off) } /* - * 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. + * Decide what to dump of a segment, part, all or none. */ -static int maydump(struct vm_area_struct *vma, unsigned long mm_flags) +static unsigned long vma_dump_size(struct vm_area_struct *vma, + unsigned long mm_flags) { /* The vma can be set up to tell us the answer directly. */ if (vma->vm_flags & VM_ALWAYSDUMP) - return 1; + goto whole; /* Do not dump I/O mapped devices or special mappings */ if (vma->vm_flags & (VM_IO | VM_RESERVED)) return 0; +#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) + /* By default, dump shared memory if mapped from an anonymous file. */ if (vma->vm_flags & VM_SHARED) { - if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0) - return test_bit(MMF_DUMP_ANON_SHARED, &mm_flags); - else - return test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags); + if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ? + FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) + goto whole; + return 0; } - /* By default, if it hasn't been written to, don't write it out. */ - if (!vma->anon_vma) - return test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags); + /* Dump segments that have been written to. */ + if (vma->anon_vma && FILTER(ANON_PRIVATE)) + goto whole; + if (vma->vm_file == NULL) + return 0; - return test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags); + 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_file != NULL && vma->vm_pgoff == 0) { + 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 (get_user(word, header) == 0 && word == magic.cmp) + return PAGE_SIZE; + } + +#undef FILTER + + return 0; + +whole: + return vma->vm_end - vma->vm_start; } /* An ELF note in memory */ @@ -1669,16 +1702,13 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un for (vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { struct elf_phdr phdr; - size_t sz; - - 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, mm_flags) ? sz : 0; - phdr.p_memsz = sz; + phdr.p_filesz = vma_dump_size(vma, mm_flags); + phdr.p_memsz = vma->vm_end - vma->vm_start; offset += phdr.p_filesz; phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0; if (vma->vm_flags & VM_WRITE) @@ -1718,13 +1748,11 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un for (vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { unsigned long addr; + unsigned long end; - if (!maydump(vma, mm_flags)) - continue; + end = vma->vm_start + vma_dump_size(vma, mm_flags); - for (addr = vma->vm_start; - addr < vma->vm_end; - addr += PAGE_SIZE) { + for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) { struct page *page; struct vm_area_struct *vma; diff --git a/include/linux/sched.h b/include/linux/sched.h index e643357eda0..cb952bc225e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -359,8 +359,9 @@ extern int get_dumpable(struct mm_struct *mm); #define MMF_DUMP_ANON_SHARED 3 #define MMF_DUMP_MAPPED_PRIVATE 4 #define MMF_DUMP_MAPPED_SHARED 5 +#define MMF_DUMP_ELF_HEADERS 6 #define MMF_DUMP_FILTER_SHIFT MMF_DUMPABLE_BITS -#define MMF_DUMP_FILTER_BITS 4 +#define MMF_DUMP_FILTER_BITS 5 #define MMF_DUMP_FILTER_MASK \ (((1 << MMF_DUMP_FILTER_BITS) - 1) << MMF_DUMP_FILTER_SHIFT) #define MMF_DUMP_FILTER_DEFAULT \ |