From ff917923f4fb9c83717ba135ee47d7e4c1567bb7 Mon Sep 17 00:00:00 2001 From: Muhammad Bilal Date: Tue, 28 Jul 2026 17:54:55 +0500 Subject: staging: rtl8723bs: fix OOB read in rtw_action_frame_parse() rtw_action_frame_parse() takes a frame_len parameter but never actually checks it before indexing into the frame body: const u8 *frame_body = frame + sizeof(struct ieee80211_hdr_3addr); ... c = frame_body[0]; ... a = frame_body[1]; frame_body already points 24 bytes (sizeof(struct ieee80211_hdr_3addr)) into frame, so reading frame_body[0] and frame_body[1] requires frame_len >= 26. A management action frame shorter than that (e.g. exactly 24 bytes, the minimum a malicious peer can send) causes a 1-2 byte out-of-bounds read. This is reachable from rtw_cfg80211_monitor_if_xmit_entry() and cfg80211_rtw_mgmt_tx() in ioctl_cfg80211.c, both of which pass attacker/user-influenced frame buffers and lengths straight through. Add the missing length check before frame_body is dereferenced. Fixes: 554c0a3abf216 ("staging: Add rtl8723bs sdio wifi driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260728125456.32359-3-meatuni001@gmail.com Signed-off-by: Greg Kroah-Hartman --- samples/kprobes/kretprobe_example.c | 108 ++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) create mode 100644 samples/kprobes/kretprobe_example.c (limited to 'samples/kprobes/kretprobe_example.c') diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c new file mode 100644 index 000000000..65d6dcafd --- /dev/null +++ b/samples/kprobes/kretprobe_example.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * kretprobe_example.c + * + * Here's a sample kernel module showing the use of return probes to + * report the return value and total time taken for probed function + * to run. + * + * usage: insmod kretprobe_example.ko func= + * + * If no func_name is specified, kernel_clone is instrumented + * + * For more information on theory of operation of kretprobes, see + * Documentation/trace/kprobes.rst + * + * Build and insert the kernel module as done in the kprobe example. + * You will see the trace data in /var/log/messages and on the console + * whenever the probed function returns. (Some messages may be suppressed + * if syslogd is configured to eliminate duplicate messages.) + */ + +#include +#include +#include +#include +#include + +static char func_name[KSYM_NAME_LEN] = "kernel_clone"; +module_param_string(func, func_name, KSYM_NAME_LEN, 0644); +MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the" + " function's execution time"); + +/* per-instance private data */ +struct my_data { + ktime_t entry_stamp; +}; + +/* Here we use the entry_handler to timestamp function entry */ +static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + struct my_data *data; + + if (!current->mm) + return 1; /* Skip kernel threads */ + + data = (struct my_data *)ri->data; + data->entry_stamp = ktime_get(); + return 0; +} +NOKPROBE_SYMBOL(entry_handler); + +/* + * Return-probe handler: Log the return value and duration. Duration may turn + * out to be zero consistently, depending upon the granularity of time + * accounting on the platform. + */ +static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + unsigned long retval = regs_return_value(regs); + struct my_data *data = (struct my_data *)ri->data; + s64 delta; + ktime_t now; + + now = ktime_get(); + delta = ktime_to_ns(ktime_sub(now, data->entry_stamp)); + pr_info("%s returned %lu and took %lld ns to execute\n", + func_name, retval, (long long)delta); + return 0; +} +NOKPROBE_SYMBOL(ret_handler); + +static struct kretprobe my_kretprobe = { + .handler = ret_handler, + .entry_handler = entry_handler, + .data_size = sizeof(struct my_data), + /* Probe up to 20 instances concurrently. */ + .maxactive = 20, +}; + +static int __init kretprobe_init(void) +{ + int ret; + + my_kretprobe.kp.symbol_name = func_name; + ret = register_kretprobe(&my_kretprobe); + if (ret < 0) { + pr_err("register_kretprobe failed, returned %d\n", ret); + return ret; + } + pr_info("Planted return probe at %s: %p\n", + my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr); + return 0; +} + +static void __exit kretprobe_exit(void) +{ + unregister_kretprobe(&my_kretprobe); + pr_info("kretprobe at %p unregistered\n", my_kretprobe.kp.addr); + + /* nmissed > 0 suggests that maxactive was set too low. */ + pr_info("Missed probing %d instances of %s\n", + my_kretprobe.nmissed, my_kretprobe.kp.symbol_name); +} + +module_init(kretprobe_init) +module_exit(kretprobe_exit) +MODULE_DESCRIPTION("sample kernel module showing the use of return probes"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1