From 85a7f9cbf8a83cfe0aca04053a832206c4ad1272 Mon Sep 17 00:00:00 2001 From: Dave Martin Date: Tue, 1 Jul 2025 14:55:55 +0100 Subject: [PATCH] regset: Add explicit core note name in struct user_regset 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 , 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 Cc: Oleg Nesterov Cc: Kees Cook Cc: Akihiko Odaki Acked-by: Alexander Gordeev # s390 Reviewed-by: Akihiko Odaki Link: https://lore.kernel.org/r/20250701135616.29630-3-Dave.Martin@arm.com Signed-off-by: Kees Cook --- 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 a43363d593e5b..f1069103ca24c 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 02417e934845e..ad1ca6fe04f42 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. -- 2.47.2