d4e85a1afe
Previously, get_sha1_hex() would read one character past the end of a null-terminated string whose strlen was an even number less than 40. Although the function correctly returned -1 in these cases, the extra memory access might have been to uninitialized (or even, conceivably, unallocated) memory. Add a check to avoid reading past the end of a string. This problem was discovered by Thomas Rast <trast@student.ethz.ch> using valgrind. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
76 lines
2.3 KiB
C
76 lines
2.3 KiB
C
#include "cache.h"
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const signed char hexval_table[256] = {
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-1, -1, -1, -1, -1, -1, -1, -1, /* 00-07 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 08-0f */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 10-17 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 18-1f */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 20-27 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 28-2f */
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0, 1, 2, 3, 4, 5, 6, 7, /* 30-37 */
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8, 9, -1, -1, -1, -1, -1, -1, /* 38-3f */
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-1, 10, 11, 12, 13, 14, 15, -1, /* 40-47 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 48-4f */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 50-57 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 58-5f */
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-1, 10, 11, 12, 13, 14, 15, -1, /* 60-67 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 68-67 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 70-77 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 78-7f */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 80-87 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 88-8f */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 90-97 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* 98-9f */
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-1, -1, -1, -1, -1, -1, -1, -1, /* a0-a7 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* a8-af */
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-1, -1, -1, -1, -1, -1, -1, -1, /* b0-b7 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* b8-bf */
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-1, -1, -1, -1, -1, -1, -1, -1, /* c0-c7 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* c8-cf */
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-1, -1, -1, -1, -1, -1, -1, -1, /* d0-d7 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* d8-df */
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-1, -1, -1, -1, -1, -1, -1, -1, /* e0-e7 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* e8-ef */
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-1, -1, -1, -1, -1, -1, -1, -1, /* f0-f7 */
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-1, -1, -1, -1, -1, -1, -1, -1, /* f8-ff */
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};
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int get_sha1_hex(const char *hex, unsigned char *sha1)
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{
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int i;
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for (i = 0; i < 20; i++) {
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unsigned int val;
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/*
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* hex[1]=='\0' is caught when val is checked below,
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* but if hex[0] is NUL we have to avoid reading
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* past the end of the string:
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*/
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if (!hex[0])
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return -1;
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val = (hexval(hex[0]) << 4) | hexval(hex[1]);
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if (val & ~0xff)
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return -1;
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*sha1++ = val;
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hex += 2;
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}
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return 0;
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}
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char *sha1_to_hex(const unsigned char *sha1)
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{
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static int bufno;
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static char hexbuffer[4][50];
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static const char hex[] = "0123456789abcdef";
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char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
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int i;
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for (i = 0; i < 20; i++) {
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unsigned int val = *sha1++;
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*buf++ = hex[val >> 4];
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*buf++ = hex[val & 0xf];
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}
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*buf = '\0';
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return buffer;
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}
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