From 6cb5bb6f117299e4178e4dfed0891c81a402bf25 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 2 Mar 2012 10:43:48 -0800 Subject: [PATCH] regset: Prevent null pointer reference on readonly regsets The regset common infrastructure assumed that regsets would always have .get and .set methods, but not necessarily .active methods. Unfortunately people have since written regsets without .set methods. Rather than putting in stub functions everywhere, handle regsets with null .get or .set methods explicitly. Signed-off-by: H. Peter Anvin Reviewed-by: Oleg Nesterov Acked-by: Roland McGrath Cc: Signed-off-by: Linus Torvalds --- fs/binfmt_elf.c | 2 +- include/linux/regset.h | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index bcb884e2d613e..07d096c49920c 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1421,7 +1421,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, for (i = 1; i < view->n; ++i) { const struct user_regset *regset = &view->regsets[i]; do_thread_regset_writeback(t->task, regset); - if (regset->core_note_type && + if (regset->core_note_type && regset->get && (!regset->active || regset->active(t->task, regset))) { int ret; size_t size = regset->n * regset->size; diff --git a/include/linux/regset.h b/include/linux/regset.h index 8abee65562230..5150fd16ef93c 100644 --- a/include/linux/regset.h +++ b/include/linux/regset.h @@ -335,6 +335,9 @@ static inline int copy_regset_to_user(struct task_struct *target, { const struct user_regset *regset = &view->regsets[setno]; + if (!regset->get) + return -EOPNOTSUPP; + if (!access_ok(VERIFY_WRITE, data, size)) return -EIO; @@ -358,6 +361,9 @@ static inline int copy_regset_from_user(struct task_struct *target, { const struct user_regset *regset = &view->regsets[setno]; + if (!regset->set) + return -EOPNOTSUPP; + if (!access_ok(VERIFY_READ, data, size)) return -EIO; -- 2.39.5