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