lkml.org 
[lkml]   [2021]   [Dec]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] kprobes: fix out-of-bounds in register_kretprobe
Hi Steve,

Can you revert this patch, because as kernel-test bot says that
this does not change anything. (rp::data_size is unsigned.)

At least it should check the result of
"sizeof(struct kretprobe_instance) + rp->data_size". Moreover,
as I sent before as "kprobes: Limit max data_size of the kretprobe instances"
the data_size must be limited to avoid overflow.

Thank you,

On Sun, 5 Dec 2021 12:26:26 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi zhangyue,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on rostedt-trace/for-next]
> [also build test WARNING on v5.16-rc3 next-20211203]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url: https://github.com/0day-ci/linux/commits/zhangyue/kprobes-fix-out-of-bounds-in-register_kretprobe/20211201-135046
> base: https://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next
> config: i386-randconfig-m021-20211203 (https://download.01.org/0day-ci/archive/20211205/202112051255.NQeIOpp8-lkp@intel.com/config)
> compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
>
> smatch warnings:
> kernel/kprobes.c:2107 register_kretprobe() warn: always true condition '(rp->data_size >= 0) => (0-u32max >= 0)'
>
> vim +2107 kernel/kprobes.c
>
> 2062
> 2063 int register_kretprobe(struct kretprobe *rp)
> 2064 {
> 2065 int ret;
> 2066 struct kretprobe_instance *inst = NULL;
> 2067 int i;
> 2068 void *addr;
> 2069
> 2070 ret = kprobe_on_func_entry(rp->kp.addr, rp->kp.symbol_name, rp->kp.offset);
> 2071 if (ret)
> 2072 return ret;
> 2073
> 2074 /* If only 'rp->kp.addr' is specified, check reregistering kprobes */
> 2075 if (rp->kp.addr && warn_kprobe_rereg(&rp->kp))
> 2076 return -EINVAL;
> 2077
> 2078 if (kretprobe_blacklist_size) {
> 2079 addr = kprobe_addr(&rp->kp);
> 2080 if (IS_ERR(addr))
> 2081 return PTR_ERR(addr);
> 2082
> 2083 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
> 2084 if (kretprobe_blacklist[i].addr == addr)
> 2085 return -EINVAL;
> 2086 }
> 2087 }
> 2088
> 2089 rp->kp.pre_handler = pre_handler_kretprobe;
> 2090 rp->kp.post_handler = NULL;
> 2091
> 2092 /* Pre-allocate memory for max kretprobe instances */
> 2093 if (rp->maxactive <= 0) {
> 2094 #ifdef CONFIG_PREEMPTION
> 2095 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
> 2096 #else
> 2097 rp->maxactive = num_possible_cpus();
> 2098 #endif
> 2099 }
> 2100 rp->freelist.head = NULL;
> 2101 rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL);
> 2102 if (!rp->rph)
> 2103 return -ENOMEM;
> 2104
> 2105 rp->rph->rp = rp;
> 2106 for (i = 0; i < rp->maxactive; i++) {
> > 2107 if (rp->data_size >= 0)
> 2108 inst = kzalloc(sizeof(struct kretprobe_instance) +
> 2109 rp->data_size, GFP_KERNEL);
> 2110 if (inst == NULL) {
> 2111 refcount_set(&rp->rph->ref, i);
> 2112 free_rp_inst(rp);
> 2113 return -ENOMEM;
> 2114 }
> 2115 inst->rph = rp->rph;
> 2116 freelist_add(&inst->freelist, &rp->freelist);
> 2117 }
> 2118 refcount_set(&rp->rph->ref, i);
> 2119
> 2120 rp->nmissed = 0;
> 2121 /* Establish function entry probe point */
> 2122 ret = register_kprobe(&rp->kp);
> 2123 if (ret != 0)
> 2124 free_rp_inst(rp);
> 2125 return ret;
> 2126 }
> 2127 EXPORT_SYMBOL_GPL(register_kretprobe);
> 2128
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org


--
Masami Hiramatsu <mhiramat@kernel.org>

\
 
 \ /
  Last update: 2021-12-06 01:23    [W:0.112 / U:6.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site