Re: [PATCH] fs/proc: add mask_secrets to prevent sensitive information leakage.
From: kernel test robot
Date: Mon May 09 2022 - 05:31:18 EST
Hi zhanglin,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linux/master]
[also build test WARNING on akpm-mm/mm-everything hnaz-mm/master linus/master v5.18-rc6 next-20220506]
[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/intel-lab-lkp/linux/commits/zhanglin/fs-proc-add-mask_secrets-to-prevent-sensitive-information-leakage/20220509-140823
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git c5eb0a61238dd6faf37f58c9ce61c9980aaffd7a
config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220509/202205091652.nHbogdH5-lkp@xxxxxxxxx/config)
compiler: arceb-elf-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/f8d1c429178d1ee0c447ee68f4e7b602c5df911f
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review zhanglin/fs-proc-add-mask_secrets-to-prevent-sensitive-information-leakage/20220509-140823
git checkout f8d1c429178d1ee0c447ee68f4e7b602c5df911f
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash fs/proc/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
All warnings (new ones prefixed by >>):
>> fs/proc/mask_secrets.c:49:8: warning: no previous prototype for 'mask_secrets' [-Wmissing-prototypes]
49 | size_t mask_secrets(struct mm_struct *mm, char __user *buf,
| ^~~~~~~~~~~~
fs/proc/mask_secrets.c: In function 'mask_secrets':
>> fs/proc/mask_secrets.c:71:13: warning: variable 'err' set but not used [-Wunused-but-set-variable]
71 | int err = 0;
| ^~~
vim +/mask_secrets +49 fs/proc/mask_secrets.c
48
> 49 size_t mask_secrets(struct mm_struct *mm, char __user *buf,
50 size_t count, loff_t pos)
51 {
52 unsigned long arg_start = 0;
53 unsigned long arg_end = 0;
54 int mask_arg_len = 0;
55 size_t remote_vm_copied = 0;
56 struct file *file = 0;
57 struct inode *inode = 0;
58 char *kbuf = 0;
59 char *progname = 0;
60 int proghash = -1;
61 int prog_found = 0;
62 char *mask_arg_start = 0;
63 char *mask_arg_end = 0;
64 struct cmdline_hashtab_item *chi = 0;
65 char *psecret = 0;
66 size_t psecret_len = 0;
67 char *pmask = 0;
68 size_t pmask_len = 0;
69 size_t size;
70 size_t total_copied = 0;
> 71 int err = 0;
72
73 if (!is_mask_secrets_enabled()) {
74 err = -EPERM;
75 goto exit_err;
76 }
77
78 spin_lock(&mm->arg_lock);
79 arg_start = mm->arg_start;
80 arg_end = mm->arg_end;
81 spin_unlock(&mm->arg_lock);
82 if (arg_start >= arg_end) {
83 err = -ERANGE;
84 goto exit_err;
85 }
86 mask_arg_len = arg_end - arg_start + 1;
87
88 file = get_mm_exe_file(mm);
89 if (!file) {
90 err = -ENOENT;
91 goto exit_err;
92 }
93 inode = file_inode(file);
94 if (!inode) {
95 err = -ENOENT;
96 goto exit_err;
97 }
98 proghash = cmdline_hash(inode->i_ino);
99 kbuf = kzalloc(max(PATH_MAX, mask_arg_len), GFP_KERNEL);
100 if (!kbuf) {
101 err = -ENOMEM;
102 goto exit_err;
103 }
104 progname = d_path(&file->f_path, kbuf, PATH_MAX);
105 if (IS_ERR_OR_NULL(progname)) {
106 err = -ENOENT;
107 goto cleanup_kbuf;
108 }
109
110 rcu_read_lock();
111 prog_found = 0;
112 hash_for_each_possible_rcu(cmdline_hashtab, chi, hlist, proghash)
113 if (strcmp(chi->progname, progname) == 0) {
114 prog_found = 1;
115 break;
116 }
117
118 if (!prog_found) {
119 rcu_read_unlock();
120 goto cleanup_kbuf;
121 }
122
123 mask_arg_start = kbuf;
124 mask_arg_end = mask_arg_start + (arg_end - arg_start);
125 remote_vm_copied = access_remote_vm(mm, arg_start, mask_arg_start, mask_arg_len, FOLL_ANON);
126 if (remote_vm_copied <= 0) {
127 rcu_read_unlock();
128 err = -EIO;
129 goto cleanup_kbuf;
130 }
131 /*skip progname */
132 for (pmask = mask_arg_start; *pmask && (pmask <= mask_arg_end); pmask++)
133 ;
134
135 if (!chi->secrets) {
136 rcu_read_unlock();
137 /*mask everything, such as: xxxconnect host port username password.*/
138 for (pmask = pmask + 1; (pmask <= mask_arg_end); pmask++)
139 for (; (pmask <= mask_arg_end) && (*pmask); pmask++)
140 *pmask = 'Z';
141 goto copydata;
142 }
143
144 for (pmask = pmask + 1; pmask <= mask_arg_end; pmask++) {
145 psecret = chi->secrets;
146 while (*psecret) {
147 psecret_len = strlen(psecret);
148 if (psecret_len < 2) {
149 rcu_read_unlock();
150 err = -EINVAL;
151 goto cleanup_kbuf;
152 }
153
154 if (strcmp(pmask, psecret) == 0) {
155 pmask += psecret_len + 1;
156 goto mask_secret;
157 }
158
159 if (strncmp(pmask, psecret, psecret_len) == 0) {
160 /*handle case: --password=xxxx */
161 if ((psecret[0] == '-') && (psecret[1] == '-'))
162 if (pmask[psecret_len] == '=') {
163 pmask += psecret_len + 1;
164 goto mask_secret;
165 }
166
167 if (psecret[0] == '-') {
168 /*handle case: -password=xxxx or -p=xxxx*/
169 if (pmask[psecret_len] == '=') {
170 pmask += psecret_len + 1;
171 goto mask_secret;
172 }
173
174 /*handle case: -pxxxx*/
175 if (psecret_len == 2) {
176 pmask += psecret_len;
177 goto mask_secret;
178 }
179 }
180 }
181
182 if (psecret_len == 2) {
183 pmask_len = strlen(pmask);
184 /*handle case: -yp xxxx, such as: useradd -rp xxxx*/
185 if ((pmask_len > 2) && (*pmask == '-')
186 && (pmask[pmask_len - 1] == psecret[1])) {
187 pmask += pmask_len + 1;
188 goto mask_secret;
189 }
190 }
191
192 psecret += psecret_len + 1;
193 }
194
195 pmask += strlen(pmask);
196 continue;
197
198 mask_secret:
199 for (; (pmask <= mask_arg_end) && (*pmask); pmask++)
200 *pmask = 'Z';
201 }
202 rcu_read_unlock();
203
204 copydata:
205 size = arg_end - pos;
206 size = min_t(size_t, size, count);
207 if (copy_to_user(buf, mask_arg_start + pos - arg_start, size))
208 goto cleanup_kbuf;
209
210 total_copied = size;
211
212 cleanup_kbuf:
213 kfree(kbuf);
214
215 exit_err:
216 return total_copied;
217 }
218
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