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 /*
47 * perserve abi due to 15b78a8e38e8 ("hex2bin: make the function hex_to_bin
48 * constant-time"
49 */
50 #ifdef __GENKSYMS__
hex_to_bin(char ch)51 int hex_to_bin(char ch)
52 #else
53 int hex_to_bin(unsigned char ch)
54 #endif
55 {
56 unsigned char cu = ch & 0xdf;
57 return -1 +
58 ((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +
59 ((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);
60 }
61 EXPORT_SYMBOL(hex_to_bin);
62
63 /**
64 * hex2bin - convert an ascii hexadecimal string to its binary representation
65 * @dst: binary result
66 * @src: ascii hexadecimal string
67 * @count: result length
68 *
69 * Return 0 on success, -EINVAL in case of bad input.
70 */
hex2bin(u8 * dst,const char * src,size_t count)71 int hex2bin(u8 *dst, const char *src, size_t count)
72 {
73 while (count--) {
74 int hi, lo;
75
76 hi = hex_to_bin(*src++);
77 if (unlikely(hi < 0))
78 return -EINVAL;
79 lo = hex_to_bin(*src++);
80 if (unlikely(lo < 0))
81 return -EINVAL;
82
83 *dst++ = (hi << 4) | lo;
84 }
85 return 0;
86 }
87 EXPORT_SYMBOL(hex2bin);
88
89 /**
90 * bin2hex - convert binary data to an ascii hexadecimal string
91 * @dst: ascii hexadecimal result
92 * @src: binary data
93 * @count: binary data length
94 */
bin2hex(char * dst,const void * src,size_t count)95 char *bin2hex(char *dst, const void *src, size_t count)
96 {
97 const unsigned char *_src = src;
98
99 while (count--)
100 dst = hex_byte_pack(dst, *_src++);
101 return dst;
102 }
103 EXPORT_SYMBOL(bin2hex);
104
105 /**
106 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
107 * @buf: data blob to dump
108 * @len: number of bytes in the @buf
109 * @rowsize: number of bytes to print per line; must be 16 or 32
110 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
111 * @linebuf: where to put the converted data
112 * @linebuflen: total size of @linebuf, including space for terminating NUL
113 * @ascii: include ASCII after the hex output
114 *
115 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
116 * 16 or 32 bytes of input data converted to hex + ASCII output.
117 *
118 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
119 * to a hex + ASCII dump at the supplied memory location.
120 * The converted output is always NUL-terminated.
121 *
122 * E.g.:
123 * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
124 * linebuf, sizeof(linebuf), true);
125 *
126 * example output buffer:
127 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
128 *
129 * Return:
130 * The amount of bytes placed in the buffer without terminating NUL. If the
131 * output was truncated, then the return value is the number of bytes
132 * (excluding the terminating NUL) which would have been written to the final
133 * string if enough space had been available.
134 */
hex_dump_to_buffer(const void * buf,size_t len,int rowsize,int groupsize,char * linebuf,size_t linebuflen,bool ascii)135 int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
136 char *linebuf, size_t linebuflen, bool ascii)
137 {
138 const u8 *ptr = buf;
139 int ngroups;
140 u8 ch;
141 int j, lx = 0;
142 int ascii_column;
143 int ret;
144
145 if (rowsize != 16 && rowsize != 32)
146 rowsize = 16;
147
148 if (len > rowsize) /* limit to one line at a time */
149 len = rowsize;
150 if (!is_power_of_2(groupsize) || groupsize > 8)
151 groupsize = 1;
152 if ((len % groupsize) != 0) /* no mixed size output */
153 groupsize = 1;
154
155 ngroups = len / groupsize;
156 ascii_column = rowsize * 2 + rowsize / groupsize + 1;
157
158 if (!linebuflen)
159 goto overflow1;
160
161 if (!len)
162 goto nil;
163
164 if (groupsize == 8) {
165 const u64 *ptr8 = buf;
166
167 for (j = 0; j < ngroups; j++) {
168 ret = snprintf(linebuf + lx, linebuflen - lx,
169 "%s%16.16llx", j ? " " : "",
170 get_unaligned(ptr8 + j));
171 if (ret >= linebuflen - lx)
172 goto overflow1;
173 lx += ret;
174 }
175 } else if (groupsize == 4) {
176 const u32 *ptr4 = buf;
177
178 for (j = 0; j < ngroups; j++) {
179 ret = snprintf(linebuf + lx, linebuflen - lx,
180 "%s%8.8x", j ? " " : "",
181 get_unaligned(ptr4 + j));
182 if (ret >= linebuflen - lx)
183 goto overflow1;
184 lx += ret;
185 }
186 } else if (groupsize == 2) {
187 const u16 *ptr2 = buf;
188
189 for (j = 0; j < ngroups; j++) {
190 ret = snprintf(linebuf + lx, linebuflen - lx,
191 "%s%4.4x", j ? " " : "",
192 get_unaligned(ptr2 + j));
193 if (ret >= linebuflen - lx)
194 goto overflow1;
195 lx += ret;
196 }
197 } else {
198 for (j = 0; j < len; j++) {
199 if (linebuflen < lx + 2)
200 goto overflow2;
201 ch = ptr[j];
202 linebuf[lx++] = hex_asc_hi(ch);
203 if (linebuflen < lx + 2)
204 goto overflow2;
205 linebuf[lx++] = hex_asc_lo(ch);
206 if (linebuflen < lx + 2)
207 goto overflow2;
208 linebuf[lx++] = ' ';
209 }
210 if (j)
211 lx--;
212 }
213 if (!ascii)
214 goto nil;
215
216 while (lx < ascii_column) {
217 if (linebuflen < lx + 2)
218 goto overflow2;
219 linebuf[lx++] = ' ';
220 }
221 for (j = 0; j < len; j++) {
222 if (linebuflen < lx + 2)
223 goto overflow2;
224 ch = ptr[j];
225 linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
226 }
227 nil:
228 linebuf[lx] = '\0';
229 return lx;
230 overflow2:
231 linebuf[lx++] = '\0';
232 overflow1:
233 return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
234 }
235 EXPORT_SYMBOL(hex_dump_to_buffer);
236
237 #ifdef CONFIG_PRINTK
238 /**
239 * print_hex_dump - print a text hex dump to syslog for a binary blob of data
240 * @level: kernel log level (e.g. KERN_DEBUG)
241 * @prefix_str: string to prefix each line with;
242 * caller supplies trailing spaces for alignment if desired
243 * @prefix_type: controls whether prefix of an offset, address, or none
244 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
245 * @rowsize: number of bytes to print per line; must be 16 or 32
246 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
247 * @buf: data blob to dump
248 * @len: number of bytes in the @buf
249 * @ascii: include ASCII after the hex output
250 *
251 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
252 * to the kernel log at the specified kernel log level, with an optional
253 * leading prefix.
254 *
255 * print_hex_dump() works on one "line" of output at a time, i.e.,
256 * 16 or 32 bytes of input data converted to hex + ASCII output.
257 * print_hex_dump() iterates over the entire input @buf, breaking it into
258 * "line size" chunks to format and print.
259 *
260 * E.g.:
261 * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
262 * 16, 1, frame->data, frame->len, true);
263 *
264 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
265 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
266 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
267 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
268 */
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)269 void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
270 int rowsize, int groupsize,
271 const void *buf, size_t len, bool ascii)
272 {
273 const u8 *ptr = buf;
274 int i, linelen, remaining = len;
275 unsigned char linebuf[32 * 3 + 2 + 32 + 1];
276
277 if (rowsize != 16 && rowsize != 32)
278 rowsize = 16;
279
280 for (i = 0; i < len; i += rowsize) {
281 linelen = min(remaining, rowsize);
282 remaining -= rowsize;
283
284 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
285 linebuf, sizeof(linebuf), ascii);
286
287 switch (prefix_type) {
288 case DUMP_PREFIX_ADDRESS:
289 printk("%s%s%p: %s\n",
290 level, prefix_str, ptr + i, linebuf);
291 break;
292 case DUMP_PREFIX_OFFSET:
293 printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
294 break;
295 default:
296 printk("%s%s%s\n", level, prefix_str, linebuf);
297 break;
298 }
299 }
300 }
301 EXPORT_SYMBOL(print_hex_dump);
302
303 #endif /* defined(CONFIG_PRINTK) */
304