There is currently hard-coded logic spread around the tree for
determining the note name for regset notes emitted in coredumps.
Now that the names are declared explicitly in <uapi/elf.h>, this can be
simplified.
In preparation for getting rid of the special-case logic, add an
explicit core_note_name field in struct user_regset for specifying the
note name explicitly. To help avoid mistakes, a convenience macro
USER_REGSET_NOTE_TYPE() is provided to set .core_note_type and
.core_note_name based on the note type.
When dumping core, use the new field to set the note name, if the
regset specifies it.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Akihiko Odaki <akihiko.odaki@daynix.com>
---
fs/binfmt_elf.c | 8 ++++++--
include/linux/regset.h | 10 ++++++++++
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index a43363d593e5..f1069103ca24 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1727,6 +1727,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
for (view_iter = 1; view_iter < view->n; ++view_iter) {
const struct user_regset *regset = &view->regsets[view_iter];
int note_type = regset->core_note_type;
+ const char *note_name = regset->core_note_name;
bool is_fpreg = note_type == NT_PRFPREG;
void *data;
int ret;
@@ -1747,8 +1748,11 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
if (is_fpreg)
SET_PR_FPVALID(&t->prstatus);
- fill_note(&t->notes[note_iter], is_fpreg ? NN_PRFPREG : "LINUX",
- note_type, ret, data);
+ if (!note_name)
+ note_name = is_fpreg ? NN_PRFPREG : "LINUX";
+
+ fill_note(&t->notes[note_iter], note_name, note_type,
+ ret, data);
info->size += notesize(&t->notes[note_iter]);
note_iter++;
diff --git a/include/linux/regset.h b/include/linux/regset.h
index 02417e934845..ad1ca6fe04f4 100644
--- a/include/linux/regset.h
+++ b/include/linux/regset.h
@@ -151,6 +151,7 @@ typedef int user_regset_writeback_fn(struct task_struct *target,
* @align: Required alignment, in bytes.
* @bias: Bias from natural indexing.
* @core_note_type: ELF note @n_type value used in core dumps.
+ * @core_note_name: ELF note name to qualify the note type.
* @regset_get: Function to fetch values.
* @set: Function to store values.
* @active: Function to report if regset is active, or %NULL.
@@ -190,6 +191,10 @@ typedef int user_regset_writeback_fn(struct task_struct *target,
*
* If nonzero, @core_note_type gives the n_type field (NT_* value)
* of the core file note in which this regset's data appears.
+ * @core_note_name specifies the note name. The preferred way to
+ * specify these two fields is to use the @USER_REGSET_NOTE_TYPE()
+ * macro.
+ *
* NT_PRSTATUS is a special case in that the regset data starts at
* offsetof(struct elf_prstatus, pr_reg) into the note data; that is
* part of the per-machine ELF formats userland knows about. In
@@ -207,8 +212,13 @@ struct user_regset {
unsigned int align;
unsigned int bias;
unsigned int core_note_type;
+ const char *core_note_name;
};
+#define USER_REGSET_NOTE_TYPE(type) \
+ .core_note_type = (NT_ ## type), \
+ .core_note_name = (NN_ ## type)
+
/**
* struct user_regset_view - available regsets
* @name: Identifier, e.g. UTS_MACHINE string.
--
2.34.1