projects/linux·blob 2c455ddc · refs

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