Commit eb3e064b authored by Takashi Iwai's avatar Takashi Iwai Committed by Vasily Gorbik
Browse files

s390/zcrypt: Use scnprintf() for avoiding potential buffer overflow 



Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Message-Id: <20200311090915.21059-1-tiwai@suse.de>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarHarald Freudenberger <freude@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 52aeda7a

drivers/s390/crypto/zcrypt_cex4.c

+21 −19
Original line number Diff line number Diff line
@@ -128,16 +128,18 @@ static ssize_t cca_mkvps_show(struct device *dev, 
		n = snprintf(buf, PAGE_SIZE, "AES NEW: - -\n");



	if (ci.cur_mk_state >= '1' && ci.cur_mk_state <= '2')

		n += snprintf(buf + n, PAGE_SIZE - n, "AES CUR: %s 0x%016llx\n",

		n += scnprintf(buf + n, PAGE_SIZE - n,

			       "AES CUR: %s 0x%016llx\n",

			       cao_state[ci.cur_mk_state - '1'], ci.cur_mkvp);

	else

		n += snprintf(buf + n, PAGE_SIZE - n, "AES CUR: - -\n");

		n += scnprintf(buf + n, PAGE_SIZE - n, "AES CUR: - -\n");



	if (ci.old_mk_state >= '1' && ci.old_mk_state <= '2')

		n += snprintf(buf + n, PAGE_SIZE - n, "AES OLD: %s 0x%016llx\n",

		n += scnprintf(buf + n, PAGE_SIZE - n,

			       "AES OLD: %s 0x%016llx\n",

			       cao_state[ci.old_mk_state - '1'], ci.old_mkvp);

	else

		n += snprintf(buf + n, PAGE_SIZE - n, "AES OLD: - -\n");

		n += scnprintf(buf + n, PAGE_SIZE - n, "AES OLD: - -\n");



	return n;

}
@@ -251,11 +253,11 @@ static ssize_t ep11_card_op_modes_show(struct device *dev, 
		if (ci.op_mode & (1 << ep11_op_modes[i].mode_bit)) {

			if (n > 0)

				buf[n++] = ' ';

			n += snprintf(buf + n, PAGE_SIZE - n,

			n += scnprintf(buf + n, PAGE_SIZE - n,

				       "%s", ep11_op_modes[i].mode_txt);

		}

	}

	n += snprintf(buf + n, PAGE_SIZE - n, "\n");

	n += scnprintf(buf + n, PAGE_SIZE - n, "\n");



	return n;

}
@@ -305,21 +307,21 @@ static ssize_t ep11_mkvps_show(struct device *dev, 
			     cwk_state[di.cur_wk_state - '0']);

		bin2hex(buf + n, di.cur_wkvp, sizeof(di.cur_wkvp));

		n += 2 * sizeof(di.cur_wkvp);

		n += snprintf(buf + n, PAGE_SIZE - n, "\n");

		n += scnprintf(buf + n, PAGE_SIZE - n, "\n");

	} else

		n = snprintf(buf, PAGE_SIZE, "WK CUR: - -\n");



	if (di.new_wk_state == '0') {

		n += snprintf(buf + n, PAGE_SIZE - n, "WK NEW: %s -\n",

		n += scnprintf(buf + n, PAGE_SIZE - n, "WK NEW: %s -\n",

			       nwk_state[di.new_wk_state - '0']);

	} else if (di.new_wk_state >= '1' && di.new_wk_state <= '2') {

		n += snprintf(buf + n, PAGE_SIZE - n, "WK NEW: %s 0x",

		n += scnprintf(buf + n, PAGE_SIZE - n, "WK NEW: %s 0x",

			       nwk_state[di.new_wk_state - '0']);

		bin2hex(buf + n, di.new_wkvp, sizeof(di.new_wkvp));

		n += 2 * sizeof(di.new_wkvp);

		n += snprintf(buf + n, PAGE_SIZE - n, "\n");

		n += scnprintf(buf + n, PAGE_SIZE - n, "\n");

	} else

		n += snprintf(buf + n, PAGE_SIZE - n, "WK NEW: - -\n");

		n += scnprintf(buf + n, PAGE_SIZE - n, "WK NEW: - -\n");



	return n;

}
@@ -346,11 +348,11 @@ static ssize_t ep11_queue_op_modes_show(struct device *dev, 
		if (di.op_mode & (1 << ep11_op_modes[i].mode_bit)) {

			if (n > 0)

				buf[n++] = ' ';

			n += snprintf(buf + n, PAGE_SIZE - n,

			n += scnprintf(buf + n, PAGE_SIZE - n,

				       "%s", ep11_op_modes[i].mode_txt);

		}

	}

	n += snprintf(buf + n, PAGE_SIZE - n, "\n");

	n += scnprintf(buf + n, PAGE_SIZE - n, "\n");



	return n;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE