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 15 const char hex_asc[] = "0123456789abcdef"; 16 EXPORT_SYMBOL(hex_asc); 17 const char hex_asc_upper[] = "0123456789ABCDEF"; 18 EXPORT_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 */ 47 int 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 } 54 EXPORT_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 */ 64 int 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 } 80 EXPORT_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 */ 88 char *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 } 96 EXPORT_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 */ 128 int 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 } 220 nil: 221 linebuf[lx] = '\0'; 222 return lx; 223 overflow2: 224 linebuf[lx++] = '\0'; 225 overflow1: 226 return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1; 227 } 228 EXPORT_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 */ 262 void 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 } 294 EXPORT_SYMBOL(print_hex_dump); 295 296 #endif /* defined(CONFIG_PRINTK) */ 297