diff options
| -rw-r--r-- | kernel/events/uprobes.c | 32 |
1 files changed, 23 insertions, 9 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index b6f0f716a884..9248ee76b4bb 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -190,6 +190,25 @@ static void copy_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t kunmap_atomic(kaddr); } +static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode) +{ + uprobe_opcode_t old_opcode; + bool is_swbp; + + copy_opcode(page, vaddr, &old_opcode); + is_swbp = is_swbp_insn(&old_opcode); + + if (is_swbp_insn(new_opcode)) { + if (is_swbp) /* register: already installed? */ + return 0; + } else { + if (!is_swbp) /* unregister: was it changed by us? */ + return -EINVAL; + } + + return 1; +} + /* * NOTE: * Expect the breakpoint instruction to be the smallest size instruction for @@ -226,6 +245,10 @@ retry: if (ret <= 0) return ret; + ret = verify_opcode(old_page, vaddr, &opcode); + if (ret <= 0) + goto put_old; + ret = -ENOMEM; new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr); if (!new_page) @@ -311,15 +334,6 @@ int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned int __weak set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) { - int result; - - result = is_swbp_at_addr(mm, vaddr); - if (!result) - return -EINVAL; - - if (result != 1) - return result; - return write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); } |