Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * lib/hexdump.c
4 : */
5 :
6 : #include <linux/types.h>
7 : #include <linux/ctype.h>
8 : #include <linux/errno.h>
9 : #include <linux/kernel.h>
10 : #include <linux/minmax.h>
11 : #include <linux/export.h>
12 : #include <asm/unaligned.h>
13 :
14 : const char hex_asc[] = "0123456789abcdef";
15 : EXPORT_SYMBOL(hex_asc);
16 : const char hex_asc_upper[] = "0123456789ABCDEF";
17 : EXPORT_SYMBOL(hex_asc_upper);
18 :
19 : /**
20 : * hex_to_bin - convert a hex digit to its real value
21 : * @ch: ascii character represents hex digit
22 : *
23 : * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
24 : * input.
25 : *
26 : * This function is used to load cryptographic keys, so it is coded in such a
27 : * way that there are no conditions or memory accesses that depend on data.
28 : *
29 : * Explanation of the logic:
30 : * (ch - '9' - 1) is negative if ch <= '9'
31 : * ('0' - 1 - ch) is negative if ch >= '0'
32 : * we "and" these two values, so the result is negative if ch is in the range
33 : * '0' ... '9'
34 : * we are only interested in the sign, so we do a shift ">> 8"; note that right
35 : * shift of a negative value is implementation-defined, so we cast the
36 : * value to (unsigned) before the shift --- we have 0xffffff if ch is in
37 : * the range '0' ... '9', 0 otherwise
38 : * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is
39 : * in the range '0' ... '9', 0 otherwise
40 : * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'
41 : * ... '9', -1 otherwise
42 : * the next line is similar to the previous one, but we need to decode both
43 : * uppercase and lowercase letters, so we use (ch & 0xdf), which converts
44 : * lowercase to uppercase
45 : */
46 0 : int hex_to_bin(unsigned char ch)
47 : {
48 0 : unsigned char cu = ch & 0xdf;
49 : return -1 +
50 0 : ((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +
51 0 : ((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);
52 : }
53 : EXPORT_SYMBOL(hex_to_bin);
54 :
55 : /**
56 : * hex2bin - convert an ascii hexadecimal string to its binary representation
57 : * @dst: binary result
58 : * @src: ascii hexadecimal string
59 : * @count: result length
60 : *
61 : * Return 0 on success, -EINVAL in case of bad input.
62 : */
63 0 : int hex2bin(u8 *dst, const char *src, size_t count)
64 : {
65 0 : while (count--) {
66 : int hi, lo;
67 :
68 0 : hi = hex_to_bin(*src++);
69 0 : if (unlikely(hi < 0))
70 : return -EINVAL;
71 0 : lo = hex_to_bin(*src++);
72 0 : if (unlikely(lo < 0))
73 : return -EINVAL;
74 :
75 0 : *dst++ = (hi << 4) | lo;
76 : }
77 : return 0;
78 : }
79 : EXPORT_SYMBOL(hex2bin);
80 :
81 : /**
82 : * bin2hex - convert binary data to an ascii hexadecimal string
83 : * @dst: ascii hexadecimal result
84 : * @src: binary data
85 : * @count: binary data length
86 : */
87 0 : char *bin2hex(char *dst, const void *src, size_t count)
88 : {
89 0 : const unsigned char *_src = src;
90 :
91 0 : while (count--)
92 0 : dst = hex_byte_pack(dst, *_src++);
93 0 : return dst;
94 : }
95 : EXPORT_SYMBOL(bin2hex);
96 :
97 : /**
98 : * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
99 : * @buf: data blob to dump
100 : * @len: number of bytes in the @buf
101 : * @rowsize: number of bytes to print per line; must be 16 or 32
102 : * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
103 : * @linebuf: where to put the converted data
104 : * @linebuflen: total size of @linebuf, including space for terminating NUL
105 : * @ascii: include ASCII after the hex output
106 : *
107 : * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
108 : * 16 or 32 bytes of input data converted to hex + ASCII output.
109 : *
110 : * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
111 : * to a hex + ASCII dump at the supplied memory location.
112 : * The converted output is always NUL-terminated.
113 : *
114 : * E.g.:
115 : * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
116 : * linebuf, sizeof(linebuf), true);
117 : *
118 : * example output buffer:
119 : * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
120 : *
121 : * Return:
122 : * The amount of bytes placed in the buffer without terminating NUL. If the
123 : * output was truncated, then the return value is the number of bytes
124 : * (excluding the terminating NUL) which would have been written to the final
125 : * string if enough space had been available.
126 : */
127 0 : int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
128 : char *linebuf, size_t linebuflen, bool ascii)
129 : {
130 0 : const u8 *ptr = buf;
131 : int ngroups;
132 : u8 ch;
133 0 : int j, lx = 0;
134 : int ascii_column;
135 : int ret;
136 :
137 0 : if (rowsize != 16 && rowsize != 32)
138 0 : rowsize = 16;
139 :
140 0 : if (len > rowsize) /* limit to one line at a time */
141 0 : len = rowsize;
142 0 : if (!is_power_of_2(groupsize) || groupsize > 8)
143 0 : groupsize = 1;
144 0 : if ((len % groupsize) != 0) /* no mixed size output */
145 0 : groupsize = 1;
146 :
147 0 : ngroups = len / groupsize;
148 0 : ascii_column = rowsize * 2 + rowsize / groupsize + 1;
149 :
150 0 : if (!linebuflen)
151 : goto overflow1;
152 :
153 0 : if (!len)
154 : goto nil;
155 :
156 0 : if (groupsize == 8) {
157 : const u64 *ptr8 = buf;
158 :
159 0 : for (j = 0; j < ngroups; j++) {
160 0 : ret = snprintf(linebuf + lx, linebuflen - lx,
161 : "%s%16.16llx", j ? " " : "",
162 0 : get_unaligned(ptr8 + j));
163 0 : if (ret >= linebuflen - lx)
164 : goto overflow1;
165 0 : lx += ret;
166 : }
167 0 : } else if (groupsize == 4) {
168 : const u32 *ptr4 = buf;
169 :
170 0 : for (j = 0; j < ngroups; j++) {
171 0 : ret = snprintf(linebuf + lx, linebuflen - lx,
172 : "%s%8.8x", j ? " " : "",
173 0 : get_unaligned(ptr4 + j));
174 0 : if (ret >= linebuflen - lx)
175 : goto overflow1;
176 0 : lx += ret;
177 : }
178 0 : } else if (groupsize == 2) {
179 : const u16 *ptr2 = buf;
180 :
181 0 : for (j = 0; j < ngroups; j++) {
182 0 : ret = snprintf(linebuf + lx, linebuflen - lx,
183 : "%s%4.4x", j ? " " : "",
184 0 : get_unaligned(ptr2 + j));
185 0 : if (ret >= linebuflen - lx)
186 : goto overflow1;
187 0 : lx += ret;
188 : }
189 : } else {
190 0 : for (j = 0; j < len; j++) {
191 0 : if (linebuflen < lx + 2)
192 : goto overflow2;
193 0 : ch = ptr[j];
194 0 : linebuf[lx++] = hex_asc_hi(ch);
195 0 : if (linebuflen < lx + 2)
196 : goto overflow2;
197 0 : linebuf[lx++] = hex_asc_lo(ch);
198 0 : if (linebuflen < lx + 2)
199 : goto overflow2;
200 0 : linebuf[lx++] = ' ';
201 : }
202 0 : if (j)
203 0 : lx--;
204 : }
205 0 : if (!ascii)
206 : goto nil;
207 :
208 0 : while (lx < ascii_column) {
209 0 : if (linebuflen < lx + 2)
210 : goto overflow2;
211 0 : linebuf[lx++] = ' ';
212 : }
213 0 : for (j = 0; j < len; j++) {
214 0 : if (linebuflen < lx + 2)
215 : goto overflow2;
216 0 : ch = ptr[j];
217 0 : linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
218 : }
219 : nil:
220 0 : linebuf[lx] = '\0';
221 0 : return lx;
222 : overflow2:
223 0 : linebuf[lx++] = '\0';
224 : overflow1:
225 0 : return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
226 : }
227 : EXPORT_SYMBOL(hex_dump_to_buffer);
228 :
229 : #ifdef CONFIG_PRINTK
230 : /**
231 : * print_hex_dump - print a text hex dump to syslog for a binary blob of data
232 : * @level: kernel log level (e.g. KERN_DEBUG)
233 : * @prefix_str: string to prefix each line with;
234 : * caller supplies trailing spaces for alignment if desired
235 : * @prefix_type: controls whether prefix of an offset, address, or none
236 : * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
237 : * @rowsize: number of bytes to print per line; must be 16 or 32
238 : * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
239 : * @buf: data blob to dump
240 : * @len: number of bytes in the @buf
241 : * @ascii: include ASCII after the hex output
242 : *
243 : * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
244 : * to the kernel log at the specified kernel log level, with an optional
245 : * leading prefix.
246 : *
247 : * print_hex_dump() works on one "line" of output at a time, i.e.,
248 : * 16 or 32 bytes of input data converted to hex + ASCII output.
249 : * print_hex_dump() iterates over the entire input @buf, breaking it into
250 : * "line size" chunks to format and print.
251 : *
252 : * E.g.:
253 : * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
254 : * 16, 1, frame->data, frame->len, true);
255 : *
256 : * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
257 : * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
258 : * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
259 : * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
260 : */
261 0 : void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
262 : int rowsize, int groupsize,
263 : const void *buf, size_t len, bool ascii)
264 : {
265 0 : const u8 *ptr = buf;
266 0 : int i, linelen, remaining = len;
267 : unsigned char linebuf[32 * 3 + 2 + 32 + 1];
268 :
269 0 : if (rowsize != 16 && rowsize != 32)
270 0 : rowsize = 16;
271 :
272 0 : for (i = 0; i < len; i += rowsize) {
273 0 : linelen = min(remaining, rowsize);
274 0 : remaining -= rowsize;
275 :
276 0 : hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
277 : linebuf, sizeof(linebuf), ascii);
278 :
279 0 : switch (prefix_type) {
280 : case DUMP_PREFIX_ADDRESS:
281 0 : printk("%s%s%p: %s\n",
282 : level, prefix_str, ptr + i, linebuf);
283 0 : break;
284 : case DUMP_PREFIX_OFFSET:
285 0 : printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
286 0 : break;
287 : default:
288 0 : printk("%s%s%s\n", level, prefix_str, linebuf);
289 0 : break;
290 : }
291 : }
292 0 : }
293 : EXPORT_SYMBOL(print_hex_dump);
294 :
295 : #endif /* defined(CONFIG_PRINTK) */
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