From 3fbff988892993a144d0f47db0348c18b4621393 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Wed, 30 Oct 2024 09:14:49 -0700 Subject: [PATCH] kprobes: Use struct_size() in __get_insn_slot() __get_insn_slot() allocates 'struct kprobe_insn_page' using a custom structure size calculation macro, KPROBE_INSN_PAGE_SIZE. Replace KPROBE_INSN_PAGE_SIZE with the struct_size() macro, which is the preferred way to calculate the size of flexible structures in the kernel because it handles overflow and makes it easier to change and audit how flexible structures are allocated across the entire tree. Link: https://lore.kernel.org/all/20241030-kprobes-fix-counted-by-annotation-v1-2-8f266001fad0@kernel.org/ (Masami modofied this to be applicable without the 1st patch in the series.) Signed-off-by: Nathan Chancellor Signed-off-by: Masami Hiramatsu (Google) --- kernel/kprobes.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 5381c6571fa2..b027a4030976 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -95,10 +95,6 @@ struct kprobe_insn_page { char slot_used[]; }; -#define KPROBE_INSN_PAGE_SIZE(slots) \ - (offsetof(struct kprobe_insn_page, slot_used) + \ - (sizeof(char) * (slots))) - static int slots_per_page(struct kprobe_insn_cache *c) { return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t)); @@ -175,7 +171,7 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c) goto retry; /* All out of space. Need to allocate a new page. */ - kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL); + kip = kmalloc(struct_size(kip, slot_used, slots_per_page(c)), GFP_KERNEL); if (!kip) goto out;