1 /*
2 * lib/hexdump.c
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation. See README and COPYING for
7 * more details.
8 */
9
10 #include <linux/types.h>
11 #include <linux/ctype.h>
12 #include <linux/errno.h>
13 #include <linux/kernel.h>
14 #include <linux/export.h>
15 #include <asm/unaligned.h>
16
17 const char hex_asc[] = "0123456789abcdef";
18 EXPORT_SYMBOL(hex_asc);
19 const char hex_asc_upper[] = "0123456789ABCDEF";
20 EXPORT_SYMBOL(hex_asc_upper);
21
22 /**
23 * hex_to_bin - convert a hex digit to its real value
24 * @ch: ascii character represents hex digit
25 *
26 * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
27 * input.
28 *
29 * This function is used to load cryptographic keys, so it is coded in such a
30 * way that there are no conditions or memory accesses that depend on data.
31 *
32 * Explanation of the logic:
33 * (ch - '9' - 1) is negative if ch <= '9'
34 * ('0' - 1 - ch) is negative if ch >= '0'
35 * we "and" these two values, so the result is negative if ch is in the range
36 * '0' ... '9'
37 * we are only interested in the sign, so we do a shift ">> 8"; note that right
38 * shift of a negative value is implementation-defined, so we cast the
39 * value to (unsigned) before the shift --- we have 0xffffff if ch is in
40 * the range '0' ... '9', 0 otherwise
41 * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is
42 * in the range '0' ... '9', 0 otherwise
43 * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'
44 * ... '9', -1 otherwise
45 * the next line is similar to the previous one, but we need to decode both
46 * uppercase and lowercase letters, so we use (ch & 0xdf), which converts
47 * lowercase to uppercase
48 */
hex_to_bin(unsigned char ch)49 int hex_to_bin(unsigned char ch)
50 {
51 unsigned char cu = ch & 0xdf;
52 return -1 +
53 ((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +
54 ((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);
55 }
56 EXPORT_SYMBOL(hex_to_bin);
57
58 /**
59 * hex2bin - convert an ascii hexadecimal string to its binary representation
60 * @dst: binary result
61 * @src: ascii hexadecimal string
62 * @count: result length
63 *
64 * Return 0 on success, -EINVAL in case of bad input.
65 */
hex2bin(u8 * dst,const char * src,size_t count)66 int hex2bin(u8 *dst, const char *src, size_t count)
67 {
68 while (count--) {
69 int hi, lo;
70
71 hi = hex_to_bin(*src++);
72 if (unlikely(hi < 0))
73 return -EINVAL;
74 lo = hex_to_bin(*src++);
75 if (unlikely(lo < 0))
76 return -EINVAL;
77
78 *dst++ = (hi << 4) | lo;
79 }
80 return 0;
81 }
82 EXPORT_SYMBOL(hex2bin);
83
84 /**
85 * bin2hex - convert binary data to an ascii hexadecimal string
86 * @dst: ascii hexadecimal result
87 * @src: binary data
88 * @count: binary data length
89 */
bin2hex(char * dst,const void * src,size_t count)90 char *bin2hex(char *dst, const void *src, size_t count)
91 {
92 const unsigned char *_src = src;
93
94 while (count--)
95 dst = hex_byte_pack(dst, *_src++);
96 return dst;
97 }
98 EXPORT_SYMBOL(bin2hex);
99
100 /**
101 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
102 * @buf: data blob to dump
103 * @len: number of bytes in the @buf
104 * @rowsize: number of bytes to print per line; must be 16 or 32
105 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
106 * @linebuf: where to put the converted data
107 * @linebuflen: total size of @linebuf, including space for terminating NUL
108 * @ascii: include ASCII after the hex output
109 *
110 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
111 * 16 or 32 bytes of input data converted to hex + ASCII output.
112 *
113 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
114 * to a hex + ASCII dump at the supplied memory location.
115 * The converted output is always NUL-terminated.
116 *
117 * E.g.:
118 * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
119 * linebuf, sizeof(linebuf), true);
120 *
121 * example output buffer:
122 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
123 *
124 * Return:
125 * The amount of bytes placed in the buffer without terminating NUL. If the
126 * output was truncated, then the return value is the number of bytes
127 * (excluding the terminating NUL) which would have been written to the final
128 * string if enough space had been available.
129 */
hex_dump_to_buffer(const void * buf,size_t len,int rowsize,int groupsize,char * linebuf,size_t linebuflen,bool ascii)130 int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
131 char *linebuf, size_t linebuflen, bool ascii)
132 {
133 const u8 *ptr = buf;
134 int ngroups;
135 u8 ch;
136 int j, lx = 0;
137 int ascii_column;
138 int ret;
139
140 if (rowsize != 16 && rowsize != 32)
141 rowsize = 16;
142
143 if (len > rowsize) /* limit to one line at a time */
144 len = rowsize;
145 if (!is_power_of_2(groupsize) || groupsize > 8)
146 groupsize = 1;
147 if ((len % groupsize) != 0) /* no mixed size output */
148 groupsize = 1;
149
150 ngroups = len / groupsize;
151 ascii_column = rowsize * 2 + rowsize / groupsize + 1;
152
153 if (!linebuflen)
154 goto overflow1;
155
156 if (!len)
157 goto nil;
158
159 if (groupsize == 8) {
160 const u64 *ptr8 = buf;
161
162 for (j = 0; j < ngroups; j++) {
163 ret = snprintf(linebuf + lx, linebuflen - lx,
164 "%s%16.16llx", j ? " " : "",
165 get_unaligned(ptr8 + j));
166 if (ret >= linebuflen - lx)
167 goto overflow1;
168 lx += ret;
169 }
170 } else if (groupsize == 4) {
171 const u32 *ptr4 = buf;
172
173 for (j = 0; j < ngroups; j++) {
174 ret = snprintf(linebuf + lx, linebuflen - lx,
175 "%s%8.8x", j ? " " : "",
176 get_unaligned(ptr4 + j));
177 if (ret >= linebuflen - lx)
178 goto overflow1;
179 lx += ret;
180 }
181 } else if (groupsize == 2) {
182 const u16 *ptr2 = buf;
183
184 for (j = 0; j < ngroups; j++) {
185 ret = snprintf(linebuf + lx, linebuflen - lx,
186 "%s%4.4x", j ? " " : "",
187 get_unaligned(ptr2 + j));
188 if (ret >= linebuflen - lx)
189 goto overflow1;
190 lx += ret;
191 }
192 } else {
193 for (j = 0; j < len; j++) {
194 if (linebuflen < lx + 2)
195 goto overflow2;
196 ch = ptr[j];
197 linebuf[lx++] = hex_asc_hi(ch);
198 if (linebuflen < lx + 2)
199 goto overflow2;
200 linebuf[lx++] = hex_asc_lo(ch);
201 if (linebuflen < lx + 2)
202 goto overflow2;
203 linebuf[lx++] = ' ';
204 }
205 if (j)
206 lx--;
207 }
208 if (!ascii)
209 goto nil;
210
211 while (lx < ascii_column) {
212 if (linebuflen < lx + 2)
213 goto overflow2;
214 linebuf[lx++] = ' ';
215 }
216 for (j = 0; j < len; j++) {
217 if (linebuflen < lx + 2)
218 goto overflow2;
219 ch = ptr[j];
220 linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
221 }
222 nil:
223 linebuf[lx] = '\0';
224 return lx;
225 overflow2:
226 linebuf[lx++] = '\0';
227 overflow1:
228 return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
229 }
230 EXPORT_SYMBOL(hex_dump_to_buffer);
231
232 #ifdef CONFIG_PRINTK
233 /**
234 * print_hex_dump - print a text hex dump to syslog for a binary blob of data
235 * @level: kernel log level (e.g. KERN_DEBUG)
236 * @prefix_str: string to prefix each line with;
237 * caller supplies trailing spaces for alignment if desired
238 * @prefix_type: controls whether prefix of an offset, address, or none
239 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
240 * @rowsize: number of bytes to print per line; must be 16 or 32
241 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
242 * @buf: data blob to dump
243 * @len: number of bytes in the @buf
244 * @ascii: include ASCII after the hex output
245 *
246 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
247 * to the kernel log at the specified kernel log level, with an optional
248 * leading prefix.
249 *
250 * print_hex_dump() works on one "line" of output at a time, i.e.,
251 * 16 or 32 bytes of input data converted to hex + ASCII output.
252 * print_hex_dump() iterates over the entire input @buf, breaking it into
253 * "line size" chunks to format and print.
254 *
255 * E.g.:
256 * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
257 * 16, 1, frame->data, frame->len, true);
258 *
259 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
260 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
261 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
262 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
263 */
print_hex_dump(const char * level,const char * prefix_str,int prefix_type,int rowsize,int groupsize,const void * buf,size_t len,bool ascii)264 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
265 int rowsize, int groupsize,
266 const void *buf, size_t len, bool ascii)
267 {
268 const u8 *ptr = buf;
269 int i, linelen, remaining = len;
270 unsigned char linebuf[32 * 3 + 2 + 32 + 1];
271
272 if (rowsize != 16 && rowsize != 32)
273 rowsize = 16;
274
275 for (i = 0; i < len; i += rowsize) {
276 linelen = min(remaining, rowsize);
277 remaining -= rowsize;
278
279 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
280 linebuf, sizeof(linebuf), ascii);
281
282 switch (prefix_type) {
283 case DUMP_PREFIX_ADDRESS:
284 printk("%s%s%p: %s\n",
285 level, prefix_str, ptr + i, linebuf);
286 break;
287 case DUMP_PREFIX_OFFSET:
288 printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
289 break;
290 default:
291 printk("%s%s%s\n", level, prefix_str, linebuf);
292 break;
293 }
294 }
295 }
296 EXPORT_SYMBOL(print_hex_dump);
297
298 #if !defined(CONFIG_DYNAMIC_DEBUG)
299 /**
300 * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params
301 * @prefix_str: string to prefix each line with;
302 * caller supplies trailing spaces for alignment if desired
303 * @prefix_type: controls whether prefix of an offset, address, or none
304 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
305 * @buf: data blob to dump
306 * @len: number of bytes in the @buf
307 *
308 * Calls print_hex_dump(), with log level of KERN_DEBUG,
309 * rowsize of 16, groupsize of 1, and ASCII output included.
310 */
print_hex_dump_bytes(const char * prefix_str,int prefix_type,const void * buf,size_t len)311 void print_hex_dump_bytes(const char *prefix_str, int prefix_type,
312 const void *buf, size_t len)
313 {
314 print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, 16, 1,
315 buf, len, true);
316 }
317 EXPORT_SYMBOL(print_hex_dump_bytes);
318 #endif /* !defined(CONFIG_DYNAMIC_DEBUG) */
319 #endif /* defined(CONFIG_PRINTK) */
320