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-rw-r--r--fs/binfmt_elf.c263
1 files changed, 47 insertions, 216 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 13d053982dd7..e7e9d0cde51a 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
+#include <linux/log2.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
@@ -421,6 +422,26 @@ static int elf_read(struct file *file, void *buf, size_t len, loff_t pos)
return 0;
}
+static unsigned long maximum_alignment(struct elf_phdr *cmds, int nr)
+{
+ unsigned long alignment = 0;
+ int i;
+
+ for (i = 0; i < nr; i++) {
+ if (cmds[i].p_type == PT_LOAD) {
+ unsigned long p_align = cmds[i].p_align;
+
+ /* skip non-power of two alignments as invalid */
+ if (!is_power_of_2(p_align))
+ continue;
+ alignment = max(alignment, p_align);
+ }
+ }
+
+ /* ensure we align to at least one page */
+ return ELF_PAGEALIGN(alignment);
+}
+
/**
* load_elf_phdrs() - load ELF program headers
* @elf_ex: ELF header of the binary whose program headers should be loaded
@@ -1008,6 +1029,7 @@ out_free_interp:
int elf_prot, elf_flags;
unsigned long k, vaddr;
unsigned long total_size = 0;
+ unsigned long alignment;
if (elf_ppnt->p_type != PT_LOAD)
continue;
@@ -1086,6 +1108,9 @@ out_free_interp:
load_bias = ELF_ET_DYN_BASE;
if (current->flags & PF_RANDOMIZE)
load_bias += arch_mmap_rnd();
+ alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum);
+ if (alignment)
+ load_bias &= ~(alignment - 1);
elf_flags |= MAP_FIXED;
} else
load_bias = 0;
@@ -1389,126 +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
{
@@ -2220,32 +2125,6 @@ static void free_note_info(struct elf_note_info *info)
#endif
-static struct vm_area_struct *first_vma(struct task_struct *tsk,
- struct vm_area_struct *gate_vma)
-{
- struct vm_area_struct *ret = tsk->mm->mmap;
-
- if (ret)
- return ret;
- return gate_vma;
-}
-/*
- * Helper function for iterating across a vma list. It ensures that the caller
- * will visit `gate_vma' prior to terminating the search.
- */
-static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
- struct vm_area_struct *gate_vma)
-{
- struct vm_area_struct *ret;
-
- ret = this_vma->vm_next;
- if (ret)
- return ret;
- if (this_vma == gate_vma)
- return NULL;
- return gate_vma;
-}
-
static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
elf_addr_t e_shoff, int segs)
{
@@ -2272,9 +2151,8 @@ static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
static int elf_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
- int segs, i;
- size_t vma_data_size = 0;
- struct vm_area_struct *vma, *gate_vma;
+ int vma_count, segs, i;
+ size_t vma_data_size;
struct elfhdr elf;
loff_t offset = 0, dataoff;
struct elf_note_info info = { };
@@ -2282,30 +2160,16 @@ static int elf_core_dump(struct coredump_params *cprm)
struct elf_shdr *shdr4extnum = NULL;
Elf_Half e_phnum;
elf_addr_t e_shoff;
- elf_addr_t *vma_filesz = NULL;
+ struct core_vma_metadata *vma_meta;
+
+ if (dump_vma_snapshot(cprm, &vma_count, &vma_meta, &vma_data_size))
+ return 0;
- /*
- * 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.
- */
-
/*
* The number of segs are recored into ELF header as 16bit value.
* Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
*/
- segs = current->mm->map_count;
- segs += elf_core_extra_phdrs();
-
- gate_vma = get_gate_vma(current->mm);
- if (gate_vma != NULL)
- segs++;
+ segs = vma_count + elf_core_extra_phdrs();
/* for notes section */
segs++;
@@ -2343,24 +2207,6 @@ static int elf_core_dump(struct coredump_params *cprm)
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- /*
- * Zero vma process will get ZERO_SIZE_PTR here.
- * Let coredump continue for register state at least.
- */
- vma_filesz = kvmalloc(array_size(sizeof(*vma_filesz), (segs - 1)),
- GFP_KERNEL);
- if (!vma_filesz)
- goto end_coredump;
-
- for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
- vma = next_vma(vma, gate_vma)) {
- unsigned long dump_size;
-
- dump_size = vma_dump_size(vma, cprm->mm_flags);
- vma_filesz[i++] = dump_size;
- vma_data_size += dump_size;
- }
-
offset += vma_data_size;
offset += elf_core_extra_data_size();
e_shoff = offset;
@@ -2381,21 +2227,23 @@ static int elf_core_dump(struct coredump_params *cprm)
goto end_coredump;
/* Write program headers for segments dump */
- for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
- vma = next_vma(vma, gate_vma)) {
+ for (i = 0; i < vma_count; i++) {
+ struct core_vma_metadata *meta = vma_meta + i;
struct elf_phdr phdr;
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
- phdr.p_vaddr = vma->vm_start;
+ phdr.p_vaddr = meta->start;
phdr.p_paddr = 0;
- phdr.p_filesz = vma_filesz[i++];
- phdr.p_memsz = vma->vm_end - vma->vm_start;
+ phdr.p_filesz = meta->dump_size;
+ phdr.p_memsz = meta->end - meta->start;
offset += phdr.p_filesz;
- phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
- if (vma->vm_flags & VM_WRITE)
+ phdr.p_flags = 0;
+ if (meta->flags & VM_READ)
+ phdr.p_flags |= PF_R;
+ if (meta->flags & VM_WRITE)
phdr.p_flags |= PF_W;
- if (vma->vm_flags & VM_EXEC)
+ if (meta->flags & VM_EXEC)
phdr.p_flags |= PF_X;
phdr.p_align = ELF_EXEC_PAGESIZE;
@@ -2417,28 +2265,11 @@ static int elf_core_dump(struct coredump_params *cprm)
if (!dump_skip(cprm, dataoff - cprm->pos))
goto end_coredump;
- for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
- vma = next_vma(vma, gate_vma)) {
- unsigned long addr;
- unsigned long end;
+ for (i = 0; i < vma_count; i++) {
+ struct core_vma_metadata *meta = vma_meta + i;
- end = vma->vm_start + vma_filesz[i++];
-
- for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
- struct page *page;
- int stop;
-
- page = get_dump_page(addr);
- if (page) {
- void *kaddr = kmap(page);
- stop = !dump_emit(cprm, kaddr, PAGE_SIZE);
- kunmap(page);
- put_page(page);
- } else
- stop = !dump_skip(cprm, PAGE_SIZE);
- if (stop)
- goto end_coredump;
- }
+ if (!dump_user_range(cprm, meta->start, meta->dump_size))
+ goto end_coredump;
}
dump_truncate(cprm);
@@ -2453,7 +2284,7 @@ static int elf_core_dump(struct coredump_params *cprm)
end_coredump:
free_note_info(&info);
kfree(shdr4extnum);
- kvfree(vma_filesz);
+ kvfree(vma_meta);
kfree(phdr4note);
return has_dumped;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 05:59:42 +0100