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authorEric W. Biederman <ebiederm@xmission.com>2022-03-08 12:55:29 -0600
committerEric W. Biederman <ebiederm@xmission.com>2022-03-08 12:55:29 -0600
commit95c5436a4883841588dae86fb0b9325f47ba5ad3 (patch)
treea6d8fa5165899d8c8cfd905784f1065e69249c21 /fs/coredump.c
parenta99a3e2efaf1f4454eb5c9176f47e66de075b134 (diff)
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 <jannh@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/coredump.c')
-rw-r--r--fs/coredump.c41
1 files changed, 23 insertions, 18 deletions
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 <trace/events/sched.h>
+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;
}