diff options
| -rw-r--r-- | fs/binfmt_elf.c | 44 | ||||
| -rw-r--r-- | fs/binfmt_elf_fdpic.c | 56 | ||||
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | mm/memory.c | 33 |
4 files changed, 66 insertions, 68 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 7c1e65d54872..442d94fe255c 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1280,9 +1280,6 @@ static int writenote(struct memelfnote *men, struct file *file, #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 void fill_elf_header(struct elfhdr *elf, int segs, u16 machine, u32 flags, u8 osabi) @@ -2016,7 +2013,8 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un goto end_coredump; /* Align to page */ - DUMP_SEEK(dataoff - foffset); + if (!dump_seek(file, dataoff - foffset)) + goto end_coredump; for (vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { @@ -2027,33 +2025,19 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, un for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) { struct page *page; - struct vm_area_struct *tmp_vma; - - if (get_user_pages(current, current->mm, addr, 1, 0, 1, - &page, &tmp_vma) <= 0) { - DUMP_SEEK(PAGE_SIZE); - } else { - if (page == ZERO_PAGE(0)) { - if (!dump_seek(file, PAGE_SIZE)) { - page_cache_release(page); - goto end_coredump; - } - } else { - void *kaddr; - flush_cache_page(tmp_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); - goto end_coredump; - } - kunmap(page); - } + int stop; + + page = get_dump_page(addr); + if (page) { + void *kaddr = kmap(page); + stop = ((size += PAGE_SIZE) > limit) || + !dump_write(file, kaddr, PAGE_SIZE); + kunmap(page); page_cache_release(page); - } + } else + stop = !dump_seek(file, PAGE_SIZE); + if (stop) + goto end_coredump; } } diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 20fbeced472b..76285471073e 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1325,9 +1325,6 @@ static int writenote(struct memelfnote *men, struct file *file) #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) { @@ -1518,6 +1515,7 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size, unsigned long *limit, unsigned long mm_flags) { struct vm_area_struct *vma; + int err = 0; for (vma = current->mm->mmap; vma; vma = vma->vm_next) { unsigned long addr; @@ -1525,43 +1523,26 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size, if (!maydump(vma, mm_flags)) 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(0)) { - page_cache_release(page); - DUMP_SEEK(file->f_pos + PAGE_SIZE); - } - 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; - } + for (addr = vma->vm_start; addr < vma->vm_end; + addr += PAGE_SIZE) { + struct page *page = get_dump_page(addr); + if (page) { + void *kaddr = kmap(page); + *size += PAGE_SIZE; + if (*size > *limit) + err = -EFBIG; + else if (!dump_write(file, kaddr, PAGE_SIZE)) + err = -EIO; kunmap(page); page_cache_release(page); - } + } else if (!dump_seek(file, file->f_pos + PAGE_SIZE)) + err = -EFBIG; + if (err) + goto out; } } - - return 0; - -end_coredump: - return -EFBIG; +out: + return err; } #endif @@ -1802,7 +1783,8 @@ static int elf_fdpic_core_dump(long signr, struct pt_regs *regs, goto end_coredump; } - DUMP_SEEK(dataoff); + if (!dump_seek(file, dataoff)) + goto end_coredump; if (elf_fdpic_dump_segments(file, &size, &limit, mm_flags) < 0) goto end_coredump; diff --git a/include/linux/mm.h b/include/linux/mm.h index 19ff81c49ba6..e41795bba95d 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -817,6 +817,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, struct page **pages, struct vm_area_struct **vmas); int get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages); +struct page *get_dump_page(unsigned long addr); extern int try_to_release_page(struct page * page, gfp_t gfp_mask); extern void do_invalidatepage(struct page *page, unsigned long offset); diff --git a/mm/memory.c b/mm/memory.c index 4b5200f5f35a..a8430ff13837 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1423,9 +1423,40 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas); } - EXPORT_SYMBOL(get_user_pages); +/** + * get_dump_page() - pin user page in memory while writing it to core dump + * @addr: user address + * + * Returns struct page pointer of user page pinned for dump, + * to be freed afterwards by page_cache_release() or put_page(). + * + * Returns NULL on any kind of failure - a hole must then be inserted into + * the corefile, to preserve alignment with its headers; and also returns + * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found - + * allowing a hole to be left in the corefile to save diskspace. + * + * Called without mmap_sem, but after all other threads have been killed. + */ +#ifdef CONFIG_ELF_CORE +struct page *get_dump_page(unsigned long addr) +{ + struct vm_area_struct *vma; + struct page *page; + + if (__get_user_pages(current, current->mm, addr, 1, + GUP_FLAGS_FORCE, &page, &vma) < 1) + return NULL; + if (page == ZERO_PAGE(0)) { + page_cache_release(page); + return NULL; + } + flush_cache_page(vma, addr, page_to_pfn(page)); + return page; +} +#endif /* CONFIG_ELF_CORE */ + pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl) { |
