From f86b334504693afe9ee6ec61416182d23c66e1ad Mon Sep 17 00:00:00 2001
From: Gabriel Kihlman <g.kihlman@yubico.com>
Date: Mon, 27 Apr 2020 14:52:53 +0200
Subject: [PATCH] Initialize bufs to 0 to avoid potentially leaking
uninitialized memory
Based on a report from Christian Reitter doing fuzzing with MSAN.
Extracts of logs:
==16111==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x4d59d4 in yk_write_to_key
/yubikey-personalization/ykcore/ykcore.c:715:8
#1 0x4d9c00 in _yk_write /yubikey-personalization/ykcore/ykcore.c:233:7
#2 0x4dc74d in yk_write_scan_map
/yubikey-personalization/ykcore/ykcore.c:357:9
#3 0x4ce352 in ykpersonalize_main
/yubikey-personalization/ykpersonalize.c:423:9
[...]
Uninitialized value was stored to memory at
#0 0x45392b in __msan_memcpy
(/yubikey-personalization/.libs/ykpersonalize+0x45392b)
#1 0x4d52f7 in yk_write_to_key
/yubikey-personalization/ykcore/ykcore.c:689:2
#2 0x4d9c00 in _yk_write /yubikey-personalization/ykcore/ykcore.c:233:7
#3 0x4dc74d in yk_write_scan_map
/yubikey-personalization/ykcore/ykcore.c:357:9
#4 0x4ce352 in ykpersonalize_main
/yubikey-personalization/ykpersonalize.c:423:9
[...]
Uninitialized value was created by an allocation of 'scan_codes' in
the stack frame of function 'ykpersonalize_main'
==18180==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x4d5a24 in yk_write_to_key /yubikey-personalization/ykcore/ykcore.c:715:8
#1 0x4d9c50 in _yk_write /yubikey-personalization/ykcore/ykcore.c:233:7
#2 0x4dae6c in yk_write_command /yubikey-personalization/ykcore/ykcore.c:288:8
#3 0x4cec93 in ykpersonalize_main /yubikey-personalization/ykpersonalize.c:440:10
Uninitialized value was stored to memory at
#0 0x45392b in __msan_memcpy (/yubikey-personalization/.libs/ykpersonalize+0x45392b)
#1 0x4d5347 in yk_write_to_key /yubikey-personalization/ykcore/ykcore.c:689:2
#2 0x4d9c50 in _yk_write /yubikey-personalization/ykcore/ykcore.c:233:7
#3 0x4dae6c in yk_write_command /yubikey-personalization/ykcore/ykcore.c:288:8
#4 0x4cec93 in ykpersonalize_main /yubikey-personalization/ykpersonalize.c:440:10
Uninitialized value was stored to memory at
#0 0x45392b in __msan_memcpy (/yubikey-personalization/.libs/ykpersonalize+0x45392b)
#1 0x4dacdb in yk_write_command /yubikey-personalization/ykcore/ykcore.c:280:3
#2 0x4cec93 in ykpersonalize_main /yubikey-personalization/ykpersonalize.c:440:10
Uninitialized value was stored to memory at
#0 0x45392b in __msan_memcpy (/yubikey-personalization/.libs/ykpersonalize+0x45392b)
#1 0x7f6fd2ea32f9 in ykp_set_fixed /yubikey-personalization/ykpers.c:787:1
#2 0x50193c in _set_fixed /yubikey-personalization/ykpers-args.c:900:2
#3 0x4ed040 in args_to_config /yubikey-personalization/ykpers-args.c:558:9
#4 0x4c865c in ykpersonalize_main /yubikey-personalization/ykpersonalize.c:167:8
Uninitialized value was created by an allocation of 'fixedbin' in the stack frame of function '_set_fixed'
#0 0x501130 in _set_fixed /yubikey-personalization/ykpers-args.c:889
---
ykpers-args.c | 8 ++++----
ykpers.c | 12 ++++++------
ykpersonalize.c | 13 +++++++------
3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/ykpers-args.c b/ykpers-args.c
index 53f7c22b..62ff7b2f 100644
--- a/ykpers-args.c
+++ b/ykpers-args.c
@@ -548,7 +548,7 @@ int args_to_config(int argc, char **argv, YKP_CONFIG *cfg, char *oathid,
else if (strncmp(optarg, "uid", 3) == 0) {
char *uid = optarg+4;
size_t uidlen;
- unsigned char uidbin[256];
+ unsigned char uidbin[256] = {0};
size_t uidbinlen = 0;
int rc;
char *uidtmp = NULL;
@@ -787,7 +787,7 @@ int args_to_config(int argc, char **argv, YKP_CONFIG *cfg, char *oathid,
size_t key_bytes = (size_t)ykp_get_supported_key_length(cfg);
int res = 0;
char *key_tmp = NULL;
- char keybuf[20];
+ char keybuf[20] = {0};
if(keylocation == 2) {
const char *prompt = " AES key, 16 bytes (32 characters hex) : ";
@@ -865,7 +865,7 @@ int args_to_config(int argc, char **argv, YKP_CONFIG *cfg, char *oathid,
static int _set_fixed(char *opt, YKP_CONFIG *cfg) {
const char *fixed = opt;
size_t fixedlen = strlen (fixed);
- unsigned char fixedbin[256];
+ unsigned char fixedbin[256] = {0};
size_t fixedbinlen = 0;
int rc = hex_modhex_decode(fixedbin, &fixedbinlen,
fixed, fixedlen,
@@ -898,7 +898,7 @@ static int _format_decimal_as_hex(uint8_t *dst, size_t dst_len, uint8_t *src)
/* For details, see YubiKey Manual 2010-09-16 section 5.3.4 - OATH-HOTP Token Identifier */
static int _format_oath_id(uint8_t *dst, size_t dst_len, uint8_t vendor, uint8_t type, uint32_t mui)
{
- uint8_t buf[8 + 1];
+ uint8_t buf[8 + 1] = {0};
if (mui > 99999999)
return 0;
diff --git a/ykpers.c b/ykpers.c
index 7941d0e3..81cb0dff 100644
--- a/ykpers.c
+++ b/ykpers.c
@@ -264,7 +264,7 @@ int ykp_get_supported_key_length(const YKP_CONFIG *cfg)
/* Decode 128 bit AES key into cfg->ykcore_config.key */
int ykp_AES_key_from_hex(YKP_CONFIG *cfg, const char *hexkey) {
- char aesbin[256];
+ char aesbin[256] = {0};
/* Make sure that the hexkey is exactly 32 characters */
if (strlen(hexkey) != 32) {
@@ -311,7 +311,7 @@ int ykp_HMAC_key_from_raw(YKP_CONFIG *cfg, const char *key) {
* and 32 bits into the first four bytes of cfg->ykcore_config.uid.
*/
int ykp_HMAC_key_from_hex(YKP_CONFIG *cfg, const char *hexkey) {
- char aesbin[256];
+ char aesbin[256] = {0};
size_t i;
/* Make sure that the hexkey is exactly 40 characters */
@@ -351,9 +351,9 @@ int ykp_AES_key_from_passphrase(YKP_CONFIG *cfg, const char *passphrase,
0
};
const char **random_place;
- uint8_t _salt[8];
+ uint8_t _salt[8] = {0};
size_t _salt_len = 0;
- unsigned char buf[sizeof(cfg->ykcore_config.key) + 4];
+ unsigned char buf[sizeof(cfg->ykcore_config.key) + 4] = {0};
int rc;
int key_bytes = ykp_get_supported_key_length(cfg);
YK_PRF_METHOD prf_method = {20, yk_hmac_sha1};
@@ -931,7 +931,7 @@ static const char str_extended_flags[] = "extended_flags";
static int _ykp_legacy_export_config(const YKP_CONFIG *cfg, char *buf, size_t len) {
if (cfg) {
- char buffer[256];
+ char buffer[256] = {0};
struct map_st *p;
unsigned char t_flags;
bool key_bits_in_uid = false;
@@ -1131,7 +1131,7 @@ int ykp_write_config(const YKP_CONFIG *cfg,
void *userdata),
void *userdata) {
if(cfg) {
- char buffer[1024];
+ char buffer[1024] = {0};
int ret = _ykp_legacy_export_config(cfg, buffer, 1024);
if(ret) {
writer(buffer, strlen(buffer), userdata);
diff --git a/ykpersonalize.c b/ykpersonalize.c
index 15338c6a..2c991e32 100644
--- a/ykpersonalize.c
+++ b/ykpersonalize.c
@@ -48,17 +48,17 @@ int main(int argc, char **argv)
FILE *outf = NULL; const char *outfname = NULL;
int data_format = YKP_FORMAT_LEGACY;
bool verbose = false;
- unsigned char access_code[256];
+ unsigned char access_code[256] = {0};
char *acc_code = NULL;
char *new_acc_code = NULL;
- unsigned char scan_codes[sizeof(SCAN_MAP)];
- unsigned char device_info[128];
+ unsigned char scan_codes[sizeof(SCAN_MAP)] = {0};
+ unsigned char device_info[128] = {0};
size_t device_info_len = 0;
YK_KEY *yk = 0;
YKP_CONFIG *cfg = ykp_alloc();
YK_STATUS *st = ykds_alloc();
bool autocommit = false;
- char data[1024];
+ char data[1024] = {0};
bool dry_run = false;
/* Options */
@@ -184,7 +184,7 @@ int main(int argc, char **argv)
}
}
if(new_acc_code) {
- unsigned char accbin[256];
+ unsigned char accbin[256] = {0};
size_t accbinlen = 0;
int rc = hex_modhex_decode (accbin, &accbinlen,
new_acc_code, strlen(new_acc_code),
@@ -261,7 +261,8 @@ int main(int argc, char **argv)
goto err;
}
} else {
- char commitbuf[256]; size_t commitlen;
+ char commitbuf[256] = {0};
+ size_t commitlen;
if (ykp_command(cfg) == SLOT_SWAP) {
fprintf(stderr, "Configuration in slot 1 and 2 will be swapped\n");
