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-rw-r--r--lib/hexdump.c73
1 files changed, 55 insertions, 18 deletions
diff --git a/lib/hexdump.c b/lib/hexdump.c
index 4af53f73c7cc..7ea09699855d 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -97,22 +97,26 @@ EXPORT_SYMBOL(bin2hex);
*
* example output buffer:
* 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
+ *
+ * Return:
+ * The amount of bytes placed in the buffer without terminating NUL. If the
+ * output was truncated, then the return value is the number of bytes
+ * (excluding the terminating NUL) which would have been written to the final
+ * string if enough space had been available.
*/
-void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
- int groupsize, char *linebuf, size_t linebuflen,
- bool ascii)
+int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
+ char *linebuf, size_t linebuflen, bool ascii)
{
const u8 *ptr = buf;
int ngroups;
u8 ch;
int j, lx = 0;
int ascii_column;
+ int ret;
if (rowsize != 16 && rowsize != 32)
rowsize = 16;
- if (!len)
- goto nil;
if (len > rowsize) /* limit to one line at a time */
len = rowsize;
if (!is_power_of_2(groupsize) || groupsize > 8)
@@ -122,27 +126,50 @@ void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
ngroups = len / groupsize;
ascii_column = rowsize * 2 + rowsize / groupsize + 1;
+
+ if (!linebuflen)
+ goto overflow1;
+
+ if (!len)
+ goto nil;
+
if (groupsize == 8) {
const u64 *ptr8 = buf;
- for (j = 0; j < ngroups; j++)
- lx += scnprintf(linebuf + lx, linebuflen - lx,
- "%s%16.16llx", j ? " " : "",
- (unsigned long long)*(ptr8 + j));
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%16.16llx", j ? " " : "",
+ (unsigned long long)*(ptr8 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
} else if (groupsize == 4) {
const u32 *ptr4 = buf;
- for (j = 0; j < ngroups; j++)
- lx += scnprintf(linebuf + lx, linebuflen - lx,
- "%s%8.8x", j ? " " : "", *(ptr4 + j));
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%8.8x", j ? " " : "",
+ *(ptr4 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
} else if (groupsize == 2) {
const u16 *ptr2 = buf;
- for (j = 0; j < ngroups; j++)
- lx += scnprintf(linebuf + lx, linebuflen - lx,
- "%s%4.4x", j ? " " : "", *(ptr2 + j));
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%4.4x", j ? " " : "",
+ *(ptr2 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
} else {
- for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) {
+ for (j = 0; j < len; j++) {
+ if (linebuflen < lx + 3)
+ goto overflow2;
ch = ptr[j];
linebuf[lx++] = hex_asc_hi(ch);
linebuf[lx++] = hex_asc_lo(ch);
@@ -154,14 +181,24 @@ void hex_dump_to_buffer(const void *buf, size_t len, int rowsize,
if (!ascii)
goto nil;
- while (lx < (linebuflen - 1) && lx < ascii_column)
+ while (lx < ascii_column) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
linebuf[lx++] = ' ';
- for (j = 0; (j < len) && (lx + 2) < linebuflen; j++) {
+ }
+ for (j = 0; j < len; j++) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
ch = ptr[j];
linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
}
nil:
+ linebuf[lx] = '\0';
+ return lx;
+overflow2:
linebuf[lx++] = '\0';
+overflow1:
+ return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
}
EXPORT_SYMBOL(hex_dump_to_buffer);