The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 325f3fb551f8cd672dbbfc4cf58b14f9ee3fc9e8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024041526-whisking-flyover-825a@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..
Possible dependencies:
325f3fb551f8 ("kprobes: Fix possible use-after-free issue on kprobe registration") 1efda38d6f9b ("kprobes: Prohibit probes in gate area") 28f6c37a2910 ("kprobes: Forbid probing on trampoline and BPF code areas") 223a76b268c9 ("kprobes: Fix coding style issues") 9c89bb8e3272 ("kprobes: treewide: Cleanup the error messages for kprobes") 02afb8d6048d ("kprobe: Simplify prepare_kprobe() by dropping redundant version") 9840cfcb97fc ("Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 325f3fb551f8cd672dbbfc4cf58b14f9ee3fc9e8 Mon Sep 17 00:00:00 2001 From: Zheng Yejian zhengyejian1@huawei.com Date: Wed, 10 Apr 2024 09:58:02 +0800 Subject: [PATCH] kprobes: Fix possible use-after-free issue on kprobe registration
When unloading a module, its state is changing MODULE_STATE_LIVE -> MODULE_STATE_GOING -> MODULE_STATE_UNFORMED. Each change will take a time. `is_module_text_address()` and `__module_text_address()` works with MODULE_STATE_LIVE and MODULE_STATE_GOING. If we use `is_module_text_address()` and `__module_text_address()` separately, there is a chance that the first one is succeeded but the next one is failed because module->state becomes MODULE_STATE_UNFORMED between those operations.
In `check_kprobe_address_safe()`, if the second `__module_text_address()` is failed, that is ignored because it expected a kernel_text address. But it may have failed simply because module->state has been changed to MODULE_STATE_UNFORMED. In this case, arm_kprobe() will try to modify non-exist module text address (use-after-free).
To fix this problem, we should not use separated `is_module_text_address()` and `__module_text_address()`, but use only `__module_text_address()` once and do `try_module_get(module)` which is only available with MODULE_STATE_LIVE.
Link: https://lore.kernel.org/all/20240410015802.265220-1-zhengyejian1@huawei.com/
Fixes: 28f6c37a2910 ("kprobes: Forbid probing on trampoline and BPF code areas") Cc: stable@vger.kernel.org Signed-off-by: Zheng Yejian zhengyejian1@huawei.com Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9d9095e81792..65adc815fc6e 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1567,10 +1567,17 @@ static int check_kprobe_address_safe(struct kprobe *p, jump_label_lock(); preempt_disable();
- /* Ensure it is not in reserved area nor out of text */ - if (!(core_kernel_text((unsigned long) p->addr) || - is_module_text_address((unsigned long) p->addr)) || - in_gate_area_no_mm((unsigned long) p->addr) || + /* Ensure the address is in a text area, and find a module if exists. */ + *probed_mod = NULL; + if (!core_kernel_text((unsigned long) p->addr)) { + *probed_mod = __module_text_address((unsigned long) p->addr); + if (!(*probed_mod)) { + ret = -EINVAL; + goto out; + } + } + /* Ensure it is not in reserved area. */ + if (in_gate_area_no_mm((unsigned long) p->addr) || within_kprobe_blacklist((unsigned long) p->addr) || jump_label_text_reserved(p->addr, p->addr) || static_call_text_reserved(p->addr, p->addr) || @@ -1580,8 +1587,7 @@ static int check_kprobe_address_safe(struct kprobe *p, goto out; }
- /* Check if 'p' is probing a module. */ - *probed_mod = __module_text_address((unsigned long) p->addr); + /* Get module refcount and reject __init functions for loaded modules. */ if (*probed_mod) { /* * We must hold a refcount of the probed module while updating