From: Eric W. Biederman ebiederm@xmission.com
commit 95c5436a4883841588dae86fb0b9325f47ba5ad3 upstream.
Move the call of dump_vma_snapshot and kvfree(vma_meta) out of the individual coredump routines into do_coredump itself. This makes the code less error prone and easier to maintain.
Make the vma snapshot available to the coredump routines in struct coredump_params. This makes it easier to change and update what is captures in the vma snapshot and will be needed for fixing fill_file_notes.
Reviewed-by: Jann Horn jannh@google.com Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/binfmt_elf.c | 20 +++++++------------- fs/binfmt_elf_fdpic.c | 18 ++++++------------ fs/coredump.c | 41 +++++++++++++++++++++++------------------ include/linux/binfmts.h | 3 +++ include/linux/coredump.h | 3 --- 5 files changed, 39 insertions(+), 46 deletions(-)
--- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -2168,8 +2168,7 @@ static void fill_extnum_info(struct elfh static int elf_core_dump(struct coredump_params *cprm) { int has_dumped = 0; - int vma_count, segs, i; - size_t vma_data_size; + int segs, i; struct elfhdr elf; loff_t offset = 0, dataoff; struct elf_note_info info = { }; @@ -2177,16 +2176,12 @@ static int elf_core_dump(struct coredump struct elf_shdr *shdr4extnum = NULL; Elf_Half e_phnum; elf_addr_t e_shoff; - struct core_vma_metadata *vma_meta; - - if (dump_vma_snapshot(cprm, &vma_count, &vma_meta, &vma_data_size)) - return 0;
/* * The number of segs are recored into ELF header as 16bit value. * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here. */ - segs = vma_count + elf_core_extra_phdrs(); + segs = cprm->vma_count + elf_core_extra_phdrs();
/* for notes section */ segs++; @@ -2225,7 +2220,7 @@ static int elf_core_dump(struct coredump
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- offset += vma_data_size; + offset += cprm->vma_data_size; offset += elf_core_extra_data_size(); e_shoff = offset;
@@ -2245,8 +2240,8 @@ static int elf_core_dump(struct coredump goto end_coredump;
/* Write program headers for segments dump */ - for (i = 0; i < vma_count; i++) { - struct core_vma_metadata *meta = vma_meta + i; + for (i = 0; i < cprm->vma_count; i++) { + struct core_vma_metadata *meta = cprm->vma_meta + i; struct elf_phdr phdr;
phdr.p_type = PT_LOAD; @@ -2283,8 +2278,8 @@ static int elf_core_dump(struct coredump /* Align to page */ dump_skip_to(cprm, dataoff);
- for (i = 0; i < vma_count; i++) { - struct core_vma_metadata *meta = vma_meta + i; + for (i = 0; i < cprm->vma_count; i++) { + struct core_vma_metadata *meta = cprm->vma_meta + i;
if (!dump_user_range(cprm, meta->start, meta->dump_size)) goto end_coredump; @@ -2301,7 +2296,6 @@ static int elf_core_dump(struct coredump end_coredump: free_note_info(&info); kfree(shdr4extnum); - kvfree(vma_meta); kfree(phdr4note); return has_dumped; } --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -1465,7 +1465,7 @@ static bool elf_fdpic_dump_segments(stru static int elf_fdpic_core_dump(struct coredump_params *cprm) { int has_dumped = 0; - int vma_count, segs; + int segs; int i; struct elfhdr *elf = NULL; loff_t offset = 0, dataoff; @@ -1480,8 +1480,6 @@ static int elf_fdpic_core_dump(struct co elf_addr_t e_shoff; struct core_thread *ct; struct elf_thread_status *tmp; - 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); @@ -1491,9 +1489,6 @@ static int elf_fdpic_core_dump(struct co 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, @@ -1513,7 +1508,7 @@ static int elf_fdpic_core_dump(struct co tmp->next = thread_list; thread_list = tmp;
- segs = vma_count + elf_core_extra_phdrs(); + segs = cprm->vma_count + elf_core_extra_phdrs();
/* for notes section */ segs++; @@ -1558,7 +1553,7 @@ static int elf_fdpic_core_dump(struct co /* Page-align dumped data */ dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- offset += vma_data_size; + offset += cprm->vma_data_size; offset += elf_core_extra_data_size(); e_shoff = offset;
@@ -1578,8 +1573,8 @@ static int elf_fdpic_core_dump(struct co goto end_coredump;
/* write program headers for segments dump */ - for (i = 0; i < vma_count; i++) { - struct core_vma_metadata *meta = vma_meta + i; + for (i = 0; i < cprm->vma_count; i++) { + struct core_vma_metadata *meta = cprm->vma_meta + i; struct elf_phdr phdr; size_t sz;
@@ -1628,7 +1623,7 @@ static int elf_fdpic_core_dump(struct co
dump_skip_to(cprm, dataoff);
- if (!elf_fdpic_dump_segments(cprm, vma_meta, vma_count)) + if (!elf_fdpic_dump_segments(cprm, cprm->vma_meta, cprm->vma_count)) goto end_coredump;
if (!elf_core_write_extra_data(cprm)) @@ -1652,7 +1647,6 @@ end_coredump: thread_list = thread_list->next; kfree(tmp); } - kvfree(vma_meta); kfree(phdr4note); kfree(elf); kfree(psinfo); --- a/fs/coredump.c +++ b/fs/coredump.c @@ -53,6 +53,8 @@
#include <trace/events/sched.h>
+static bool dump_vma_snapshot(struct coredump_params *cprm); + int core_uses_pid; unsigned int core_pipe_limit; char core_pattern[CORENAME_MAX_SIZE] = "core"; @@ -601,6 +603,7 @@ void do_coredump(const kernel_siginfo_t * by any locks. */ .mm_flags = mm->flags, + .vma_meta = NULL, };
audit_core_dumps(siginfo->si_signo); @@ -815,6 +818,9 @@ void do_coredump(const kernel_siginfo_t pr_info("Core dump to |%s disabled\n", cn.corename); goto close_fail; } + if (!dump_vma_snapshot(&cprm)) + goto close_fail; + file_start_write(cprm.file); core_dumped = binfmt->core_dump(&cprm); /* @@ -828,6 +834,7 @@ void do_coredump(const kernel_siginfo_t dump_emit(&cprm, "", 1); } file_end_write(cprm.file); + kvfree(cprm.vma_meta); } if (ispipe && core_pipe_limit) wait_for_dump_helpers(cprm.file); @@ -1108,14 +1115,11 @@ static struct vm_area_struct *next_vma(s * 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) +static bool dump_vma_snapshot(struct coredump_params *cprm) { 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 @@ -1123,20 +1127,21 @@ int dump_vma_snapshot(struct coredump_pa * mmap_lock in read mode. */ if (mmap_write_lock_killable(mm)) - return -EINTR; + return false;
+ cprm->vma_data_size = 0; gate_vma = get_gate_vma(mm); - *vma_count = mm->map_count + (gate_vma ? 1 : 0); + cprm->vma_count = mm->map_count + (gate_vma ? 1 : 0);
- *vma_meta = kvmalloc_array(*vma_count, sizeof(**vma_meta), GFP_KERNEL); - if (!*vma_meta) { + cprm->vma_meta = kvmalloc_array(cprm->vma_count, sizeof(*cprm->vma_meta), GFP_KERNEL); + if (!cprm->vma_meta) { mmap_write_unlock(mm); - return -ENOMEM; + return false; }
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; + struct core_vma_metadata *m = cprm->vma_meta + i;
m->start = vma->vm_start; m->end = vma->vm_end; @@ -1146,13 +1151,14 @@ int dump_vma_snapshot(struct coredump_pa
mmap_write_unlock(mm);
- if (WARN_ON(i != *vma_count)) { - kvfree(*vma_meta); - return -EFAULT; + if (WARN_ON(i != cprm->vma_count)) { + kvfree(cprm->vma_meta); + return false; }
- for (i = 0; i < *vma_count; i++) { - struct core_vma_metadata *m = (*vma_meta) + i; + + for (i = 0; i < cprm->vma_count; i++) { + struct core_vma_metadata *m = cprm->vma_meta + i;
if (m->dump_size == DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER) { char elfmag[SELFMAG]; @@ -1165,9 +1171,8 @@ int dump_vma_snapshot(struct coredump_pa } }
- vma_data_size += m->dump_size; + cprm->vma_data_size += m->dump_size; }
- *vma_data_size_ptr = vma_data_size; - return 0; + return true; } --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -87,6 +87,9 @@ struct coredump_params { loff_t written; loff_t pos; loff_t to_skip; + int vma_count; + size_t vma_data_size; + struct core_vma_metadata *vma_meta; };
/* --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -29,9 +29,6 @@ extern int dump_emit(struct coredump_par extern int dump_align(struct coredump_params *cprm, int align); 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); extern void do_coredump(const kernel_siginfo_t *siginfo); #else static inline void do_coredump(const kernel_siginfo_t *siginfo) {}