e4d8a29997
If we pass too short string to "hex2bin" (and the string size without
the terminating NUL character is even), "hex2bin" reads one byte after
the terminating NUL character. This patch fixes it.
Note that hex_to_bin returns -1 on error and hex2bin return -EINVAL on
error - so we can't just return the variable "hi" or "lo" on error.
This inconsistency may be fixed in the next merge window, but for the
purpose of fixing this bug, we just preserve the existing behavior and
return -1 and -EINVAL.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Fixes: b78049831f ("lib: add error checking to hex2bin")
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
296 lines
8.5 KiB
C
296 lines
8.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* lib/hexdump.c
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*/
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#include <linux/types.h>
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#include <linux/ctype.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/minmax.h>
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#include <linux/export.h>
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#include <asm/unaligned.h>
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const char hex_asc[] = "0123456789abcdef";
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EXPORT_SYMBOL(hex_asc);
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const char hex_asc_upper[] = "0123456789ABCDEF";
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EXPORT_SYMBOL(hex_asc_upper);
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/**
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* hex_to_bin - convert a hex digit to its real value
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* @ch: ascii character represents hex digit
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*
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* hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
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* input.
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*
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* This function is used to load cryptographic keys, so it is coded in such a
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* way that there are no conditions or memory accesses that depend on data.
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*
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* Explanation of the logic:
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* (ch - '9' - 1) is negative if ch <= '9'
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* ('0' - 1 - ch) is negative if ch >= '0'
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* we "and" these two values, so the result is negative if ch is in the range
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* '0' ... '9'
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* we are only interested in the sign, so we do a shift ">> 8"; note that right
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* shift of a negative value is implementation-defined, so we cast the
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* value to (unsigned) before the shift --- we have 0xffffff if ch is in
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* the range '0' ... '9', 0 otherwise
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* we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is
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* in the range '0' ... '9', 0 otherwise
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* we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'
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* ... '9', -1 otherwise
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* the next line is similar to the previous one, but we need to decode both
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* uppercase and lowercase letters, so we use (ch & 0xdf), which converts
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* lowercase to uppercase
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*/
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int hex_to_bin(unsigned char ch)
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{
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unsigned char cu = ch & 0xdf;
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return -1 +
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((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +
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((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);
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}
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EXPORT_SYMBOL(hex_to_bin);
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/**
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* hex2bin - convert an ascii hexadecimal string to its binary representation
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* @dst: binary result
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* @src: ascii hexadecimal string
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* @count: result length
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*
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* Return 0 on success, -EINVAL in case of bad input.
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*/
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int hex2bin(u8 *dst, const char *src, size_t count)
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{
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while (count--) {
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int hi, lo;
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hi = hex_to_bin(*src++);
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if (unlikely(hi < 0))
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return -EINVAL;
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lo = hex_to_bin(*src++);
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if (unlikely(lo < 0))
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return -EINVAL;
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*dst++ = (hi << 4) | lo;
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}
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return 0;
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}
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EXPORT_SYMBOL(hex2bin);
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/**
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* bin2hex - convert binary data to an ascii hexadecimal string
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* @dst: ascii hexadecimal result
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* @src: binary data
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* @count: binary data length
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*/
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char *bin2hex(char *dst, const void *src, size_t count)
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{
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const unsigned char *_src = src;
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while (count--)
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dst = hex_byte_pack(dst, *_src++);
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return dst;
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}
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EXPORT_SYMBOL(bin2hex);
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/**
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* hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
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* @buf: data blob to dump
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* @len: number of bytes in the @buf
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* @rowsize: number of bytes to print per line; must be 16 or 32
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* @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
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* @linebuf: where to put the converted data
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* @linebuflen: total size of @linebuf, including space for terminating NUL
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* @ascii: include ASCII after the hex output
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*
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* hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
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* 16 or 32 bytes of input data converted to hex + ASCII output.
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*
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* Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
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* to a hex + ASCII dump at the supplied memory location.
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* The converted output is always NUL-terminated.
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*
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* E.g.:
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* hex_dump_to_buffer(frame->data, frame->len, 16, 1,
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* linebuf, sizeof(linebuf), true);
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*
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* example output buffer:
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* 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
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*
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* Return:
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* The amount of bytes placed in the buffer without terminating NUL. If the
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* output was truncated, then the return value is the number of bytes
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* (excluding the terminating NUL) which would have been written to the final
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* string if enough space had been available.
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*/
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int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
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char *linebuf, size_t linebuflen, bool ascii)
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{
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const u8 *ptr = buf;
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int ngroups;
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u8 ch;
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int j, lx = 0;
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int ascii_column;
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int ret;
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if (rowsize != 16 && rowsize != 32)
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rowsize = 16;
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if (len > rowsize) /* limit to one line at a time */
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len = rowsize;
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if (!is_power_of_2(groupsize) || groupsize > 8)
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groupsize = 1;
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if ((len % groupsize) != 0) /* no mixed size output */
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groupsize = 1;
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ngroups = len / groupsize;
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ascii_column = rowsize * 2 + rowsize / groupsize + 1;
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if (!linebuflen)
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goto overflow1;
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if (!len)
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goto nil;
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if (groupsize == 8) {
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const u64 *ptr8 = buf;
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for (j = 0; j < ngroups; j++) {
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ret = snprintf(linebuf + lx, linebuflen - lx,
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"%s%16.16llx", j ? " " : "",
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get_unaligned(ptr8 + j));
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if (ret >= linebuflen - lx)
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goto overflow1;
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lx += ret;
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}
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} else if (groupsize == 4) {
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const u32 *ptr4 = buf;
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for (j = 0; j < ngroups; j++) {
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ret = snprintf(linebuf + lx, linebuflen - lx,
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"%s%8.8x", j ? " " : "",
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get_unaligned(ptr4 + j));
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if (ret >= linebuflen - lx)
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goto overflow1;
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lx += ret;
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}
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} else if (groupsize == 2) {
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const u16 *ptr2 = buf;
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for (j = 0; j < ngroups; j++) {
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ret = snprintf(linebuf + lx, linebuflen - lx,
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"%s%4.4x", j ? " " : "",
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get_unaligned(ptr2 + j));
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if (ret >= linebuflen - lx)
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goto overflow1;
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lx += ret;
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}
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} else {
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for (j = 0; j < len; j++) {
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if (linebuflen < lx + 2)
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goto overflow2;
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ch = ptr[j];
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linebuf[lx++] = hex_asc_hi(ch);
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if (linebuflen < lx + 2)
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goto overflow2;
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linebuf[lx++] = hex_asc_lo(ch);
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if (linebuflen < lx + 2)
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goto overflow2;
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linebuf[lx++] = ' ';
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}
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if (j)
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lx--;
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}
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if (!ascii)
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goto nil;
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while (lx < ascii_column) {
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if (linebuflen < lx + 2)
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goto overflow2;
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linebuf[lx++] = ' ';
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}
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for (j = 0; j < len; j++) {
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if (linebuflen < lx + 2)
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goto overflow2;
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ch = ptr[j];
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linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
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}
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nil:
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linebuf[lx] = '\0';
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return lx;
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overflow2:
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linebuf[lx++] = '\0';
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overflow1:
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return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
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}
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EXPORT_SYMBOL(hex_dump_to_buffer);
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#ifdef CONFIG_PRINTK
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/**
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* print_hex_dump - print a text hex dump to syslog for a binary blob of data
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* @level: kernel log level (e.g. KERN_DEBUG)
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* @prefix_str: string to prefix each line with;
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* caller supplies trailing spaces for alignment if desired
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* @prefix_type: controls whether prefix of an offset, address, or none
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* is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
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* @rowsize: number of bytes to print per line; must be 16 or 32
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* @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
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* @buf: data blob to dump
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* @len: number of bytes in the @buf
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* @ascii: include ASCII after the hex output
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*
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* Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
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* to the kernel log at the specified kernel log level, with an optional
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* leading prefix.
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*
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* print_hex_dump() works on one "line" of output at a time, i.e.,
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* 16 or 32 bytes of input data converted to hex + ASCII output.
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* print_hex_dump() iterates over the entire input @buf, breaking it into
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* "line size" chunks to format and print.
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*
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* E.g.:
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* print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
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* 16, 1, frame->data, frame->len, true);
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*
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* Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
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* 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
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* Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
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* ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
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*/
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void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
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int rowsize, int groupsize,
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const void *buf, size_t len, bool ascii)
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{
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const u8 *ptr = buf;
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int i, linelen, remaining = len;
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unsigned char linebuf[32 * 3 + 2 + 32 + 1];
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if (rowsize != 16 && rowsize != 32)
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rowsize = 16;
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for (i = 0; i < len; i += rowsize) {
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linelen = min(remaining, rowsize);
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remaining -= rowsize;
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hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
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linebuf, sizeof(linebuf), ascii);
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switch (prefix_type) {
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case DUMP_PREFIX_ADDRESS:
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printk("%s%s%p: %s\n",
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level, prefix_str, ptr + i, linebuf);
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break;
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case DUMP_PREFIX_OFFSET:
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printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
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break;
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default:
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printk("%s%s%s\n", level, prefix_str, linebuf);
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break;
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}
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}
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}
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EXPORT_SYMBOL(print_hex_dump);
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#endif /* defined(CONFIG_PRINTK) */
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