From 95c5436a4883841588dae86fb0b9325f47ba5ad3 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 8 Mar 2022 12:55:29 -0600 Subject: coredump: Snapshot the vmas in do_coredump 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 Reviewed-by: Kees Cook Signed-off-by: "Eric W. Biederman" --- fs/coredump.c | 41 +++++++++++++++++++++++------------------ 1 file changed, 23 insertions(+), 18 deletions(-) (limited to 'fs/coredump.c') diff --git a/fs/coredump.c b/fs/coredump.c index b73817712dd2..88ac67994d03 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -54,6 +54,8 @@ #include +static bool dump_vma_snapshot(struct coredump_params *cprm); + static int core_uses_pid; static unsigned int core_pipe_limit; static char core_pattern[CORENAME_MAX_SIZE] = "core"; @@ -532,6 +534,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) * by any locks. */ .mm_flags = mm->flags, + .vma_meta = NULL, }; audit_core_dumps(siginfo->si_signo); @@ -746,6 +749,9 @@ void do_coredump(const kernel_siginfo_t *siginfo) 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); /* @@ -759,6 +765,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) dump_emit(&cprm, "", 1); } file_end_write(cprm.file); + kvfree(cprm.vma_meta); } if (ispipe && core_pipe_limit) wait_for_dump_helpers(cprm.file); @@ -1096,14 +1103,11 @@ static struct vm_area_struct *next_vma(struct vm_area_struct *this_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) +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 @@ -1111,20 +1115,21 @@ int dump_vma_snapshot(struct coredump_params *cprm, int *vma_count, * 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; @@ -1134,13 +1139,14 @@ int dump_vma_snapshot(struct coredump_params *cprm, int *vma_count, 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]; @@ -1153,9 +1159,8 @@ int dump_vma_snapshot(struct coredump_params *cprm, int *vma_count, } } - vma_data_size += m->dump_size; + cprm->vma_data_size += m->dump_size; } - *vma_data_size_ptr = vma_data_size; - return 0; + return true; } -- cgit v1.2.3