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9#include <linux/module.h>
10#include <linux/string.h>
11#include <linux/stat.h>
12#include <linux/binfmts.h>
13#include <linux/init.h>
14#include <linux/file.h>
15#include <linux/err.h>
16#include <linux/fs.h>
17
18static inline bool spacetab(char c) { return c == ' ' || c == '\t'; }
19static inline const char *next_non_spacetab(const char *first, const char *last)
20{
21 for (; first <= last; first++)
22 if (!spacetab(*first))
23 return first;
24 return NULL;
25}
26static inline const char *next_terminator(const char *first, const char *last)
27{
28 for (; first <= last; first++)
29 if (spacetab(*first) || !*first)
30 return first;
31 return NULL;
32}
33
34static int load_script(struct linux_binprm *bprm)
35{
36 const char *i_name, *i_sep, *i_arg, *i_end, *buf_end;
37 struct file *file;
38 int retval;
39
40
41 if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!'))
42 return -ENOEXEC;
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58 buf_end = bprm->buf + sizeof(bprm->buf) - 1;
59 i_end = strnchr(bprm->buf, sizeof(bprm->buf), '\n');
60 if (!i_end) {
61 i_end = next_non_spacetab(bprm->buf + 2, buf_end);
62 if (!i_end)
63 return -ENOEXEC;
64
65
66
67
68 if (!next_terminator(i_end, buf_end))
69 return -ENOEXEC;
70 i_end = buf_end;
71 }
72
73 while (spacetab(i_end[-1]))
74 i_end--;
75
76
77 i_name = next_non_spacetab(bprm->buf+2, i_end);
78 if (!i_name || (i_name == i_end))
79 return -ENOEXEC;
80
81
82 i_arg = NULL;
83 i_sep = next_terminator(i_name, i_end);
84 if (i_sep && (*i_sep != '\0'))
85 i_arg = next_non_spacetab(i_sep, i_end);
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92
93 if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE)
94 return -ENOENT;
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105
106 retval = remove_arg_zero(bprm);
107 if (retval)
108 return retval;
109 retval = copy_string_kernel(bprm->interp, bprm);
110 if (retval < 0)
111 return retval;
112 bprm->argc++;
113 *((char *)i_end) = '\0';
114 if (i_arg) {
115 *((char *)i_sep) = '\0';
116 retval = copy_string_kernel(i_arg, bprm);
117 if (retval < 0)
118 return retval;
119 bprm->argc++;
120 }
121 retval = copy_string_kernel(i_name, bprm);
122 if (retval)
123 return retval;
124 bprm->argc++;
125 retval = bprm_change_interp(i_name, bprm);
126 if (retval < 0)
127 return retval;
128
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131
132 file = open_exec(i_name);
133 if (IS_ERR(file))
134 return PTR_ERR(file);
135
136 bprm->interpreter = file;
137 return 0;
138}
139
140static struct linux_binfmt script_format = {
141 .module = THIS_MODULE,
142 .load_binary = load_script,
143};
144
145static int __init init_script_binfmt(void)
146{
147 register_binfmt(&script_format);
148 return 0;
149}
150
151static void __exit exit_script_binfmt(void)
152{
153 unregister_binfmt(&script_format);
154}
155
156core_initcall(init_script_binfmt);
157module_exit(exit_script_binfmt);
158MODULE_LICENSE("GPL");
159