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-rw-r--r--fs/binfmt_elf.c100
-rw-r--r--fs/binfmt_elf_fdpic.c67
-rw-r--r--fs/coredump.c81
-rw-r--r--include/linux/coredump.h10
4 files changed, 138 insertions, 120 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index c1756fd8d10b..e7e9d0cde51a 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -2125,32 +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)
{
@@ -2177,9 +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 = { };
@@ -2187,30 +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++;
@@ -2248,24 +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;
@@ -2286,21 +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;
@@ -2322,9 +2265,10 @@ 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)) {
- if (!dump_user_range(cprm, vma->vm_start, vma_filesz[i++]))
+ for (i = 0; i < vma_count; i++) {
+ struct core_vma_metadata *meta = vma_meta + i;
+
+ if (!dump_user_range(cprm, meta->start, meta->dump_size))
goto end_coredump;
}
dump_truncate(cprm);
@@ -2340,7 +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;
}
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index f531c6198864..be4062b8ba75 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1454,29 +1454,21 @@ static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
/*
* dump the segments for an MMU process
*/
-static bool elf_fdpic_dump_segments(struct coredump_params *cprm)
+static bool elf_fdpic_dump_segments(struct coredump_params *cprm,
+ struct core_vma_metadata *vma_meta,
+ int vma_count)
{
- struct vm_area_struct *vma;
+ int i;
- for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
- unsigned long size = vma_dump_size(vma, cprm->mm_flags);
+ for (i = 0; i < vma_count; i++) {
+ struct core_vma_metadata *meta = vma_meta + i;
- if (!dump_user_range(cprm, vma->vm_start, size))
+ if (!dump_user_range(cprm, meta->start, meta->dump_size))
return false;
}
return true;
}
-static size_t elf_core_vma_data_size(unsigned long mm_flags)
-{
- struct vm_area_struct *vma;
- size_t size = 0;
-
- for (vma = current->mm->mmap; vma; vma = vma->vm_next)
- size += vma_dump_size(vma, mm_flags);
- return size;
-}
-
/*
* Actual dumper
*
@@ -1487,9 +1479,8 @@ static size_t elf_core_vma_data_size(unsigned long mm_flags)
static int elf_fdpic_core_dump(struct coredump_params *cprm)
{
int has_dumped = 0;
- int segs;
+ int vma_count, segs;
int i;
- struct vm_area_struct *vma;
struct elfhdr *elf = NULL;
loff_t offset = 0, dataoff;
struct memelfnote psinfo_note, auxv_note;
@@ -1503,18 +1494,8 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
elf_addr_t e_shoff;
struct core_thread *ct;
struct elf_thread_status *tmp;
-
- /*
- * 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.
- */
+ struct core_vma_metadata *vma_meta = NULL;
+ size_t vma_data_size;
/* alloc memory for large data structures: too large to be on stack */
elf = kmalloc(sizeof(*elf), GFP_KERNEL);
@@ -1524,6 +1505,9 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
if (!psinfo)
goto end_coredump;
+ if (dump_vma_snapshot(cprm, &vma_count, &vma_meta, &vma_data_size))
+ goto end_coredump;
+
for (ct = current->mm->core_state->dumper.next;
ct; ct = ct->next) {
tmp = elf_dump_thread_status(cprm->siginfo->si_signo,
@@ -1543,8 +1527,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
tmp->next = thread_list;
thread_list = tmp;
- segs = current->mm->map_count;
- segs += elf_core_extra_phdrs();
+ segs = vma_count + elf_core_extra_phdrs();
/* for notes section */
segs++;
@@ -1589,7 +1572,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
/* Page-align dumped data */
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- offset += elf_core_vma_data_size(cprm->mm_flags);
+ offset += vma_data_size;
offset += elf_core_extra_data_size();
e_shoff = offset;
@@ -1609,23 +1592,26 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
goto end_coredump;
/* write program headers for segments dump */
- for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
+ for (i = 0; i < vma_count; i++) {
+ struct core_vma_metadata *meta = vma_meta + i;
struct elf_phdr phdr;
size_t sz;
- sz = vma->vm_end - vma->vm_start;
+ sz = meta->end - meta->start;
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_dump_size(vma, cprm->mm_flags);
+ phdr.p_filesz = meta->dump_size;
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 = 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;
@@ -1657,7 +1643,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
if (!dump_skip(cprm, dataoff - cprm->pos))
goto end_coredump;
- if (!elf_fdpic_dump_segments(cprm))
+ if (!elf_fdpic_dump_segments(cprm, vma_meta, vma_count))
goto end_coredump;
if (!elf_core_write_extra_data(cprm))
@@ -1681,6 +1667,7 @@ end_coredump:
thread_list = thread_list->next;
kfree(tmp);
}
+ kvfree(vma_meta);
kfree(phdr4note);
kfree(elf);
kfree(psinfo);
diff --git a/fs/coredump.c b/fs/coredump.c
index 4ef4c49a65b7..0cd9056d79cc 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -971,7 +971,8 @@ static bool always_dump_vma(struct vm_area_struct *vma)
/*
* 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)
+static unsigned long vma_dump_size(struct vm_area_struct *vma,
+ unsigned long mm_flags)
{
#define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type))
@@ -1037,3 +1038,81 @@ unsigned long vma_dump_size(struct vm_area_struct *vma, unsigned long mm_flags)
whole:
return vma->vm_end - vma->vm_start;
}
+
+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;
+}
+
+/*
+ * Under the mmap_lock, take a snapshot of relevant information about the task's
+ * VMAs.
+ */
+int dump_vma_snapshot(struct coredump_params *cprm, int *vma_count,
+ struct core_vma_metadata **vma_meta,
+ size_t *vma_data_size_ptr)
+{
+ struct vm_area_struct *vma, *gate_vma;
+ struct mm_struct *mm = current->mm;
+ int i;
+ size_t vma_data_size = 0;
+
+ /*
+ * Once the stack expansion code is fixed to not change VMA bounds
+ * under mmap_lock in read mode, this can be changed to take the
+ * mmap_lock in read mode.
+ */
+ if (mmap_write_lock_killable(mm))
+ return -EINTR;
+
+ gate_vma = get_gate_vma(mm);
+ *vma_count = mm->map_count + (gate_vma ? 1 : 0);
+
+ *vma_meta = kvmalloc_array(*vma_count, sizeof(**vma_meta), GFP_KERNEL);
+ if (!*vma_meta) {
+ mmap_write_unlock(mm);
+ return -ENOMEM;
+ }
+
+ for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
+ vma = next_vma(vma, gate_vma), i++) {
+ struct core_vma_metadata *m = (*vma_meta) + i;
+
+ m->start = vma->vm_start;
+ m->end = vma->vm_end;
+ m->flags = vma->vm_flags;
+ m->dump_size = vma_dump_size(vma, cprm->mm_flags);
+
+ vma_data_size += m->dump_size;
+ }
+
+ mmap_write_unlock(mm);
+
+ if (WARN_ON(i != *vma_count))
+ return -EFAULT;
+
+ *vma_data_size_ptr = vma_data_size;
+ return 0;
+}
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index bfecb8d79a7f..e58e8c207782 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -7,6 +7,12 @@
#include <linux/fs.h>
#include <asm/siginfo.h>
+struct core_vma_metadata {
+ unsigned long start, end;
+ unsigned long flags;
+ unsigned long dump_size;
+};
+
/*
* These are the only things you should do on a core-file: use only these
* functions to write out all the necessary info.
@@ -16,9 +22,11 @@ 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);
+int dump_vma_snapshot(struct coredump_params *cprm, int *vma_count,
+ struct core_vma_metadata **vma_meta,
+ size_t *vma_data_size_ptr);
#ifdef CONFIG_COREDUMP
extern void do_coredump(const kernel_siginfo_t *siginfo);
#else
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-29 21:45:11 +0000