diff options
| author | Dr. Stephen Henson <steve@openssl.org> | 2016-08-05 14:26:03 +0100 |
|---|---|---|
| committer | Dr. Stephen Henson <steve@openssl.org> | 2016-08-16 00:19:19 +0100 |
| commit | 07bed46f332fce8c1d157689a2cdf915a982ae34 (patch) | |
| tree | 8b5289bce64b0cfdb46903714ae3aacbfa459d33 | |
| parent | 40c60b0d7389aa479cf7474a080737e901944d0d (diff) | |
Check for errors in BN_bn2dec()
If an oversize BIGNUM is presented to BN_bn2dec() it can cause
BN_div_word() to fail and not reduce the value of 't' resulting
in OOB writes to the bn_data buffer and eventually crashing.
Fix by checking return value of BN_div_word() and checking writes
don't overflow buffer.
Thanks to Shi Lei for reporting this bug.
CVE-2016-2182
Reviewed-by: Tim Hudson <tjh@openssl.org>
| -rw-r--r-- | crypto/bn/bn_print.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/crypto/bn/bn_print.c b/crypto/bn/bn_print.c index 8672c7e3b3..f6030ff14c 100644 --- a/crypto/bn/bn_print.c +++ b/crypto/bn/bn_print.c @@ -62,6 +62,7 @@ char *BN_bn2dec(const BIGNUM *a) char *p; BIGNUM *t = NULL; BN_ULONG *bn_data = NULL, *lp; + int bn_data_num; /*- * get an upper bound for the length of the decimal integer @@ -71,7 +72,8 @@ char *BN_bn2dec(const BIGNUM *a) */ i = BN_num_bits(a) * 3; num = (i / 10 + i / 1000 + 1) + 1; - bn_data = OPENSSL_malloc((num / BN_DEC_NUM + 1) * sizeof(BN_ULONG)); + bn_data_num = num / BN_DEC_NUM + 1; + bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG)); buf = OPENSSL_malloc(num + 3); if ((buf == NULL) || (bn_data == NULL)) { BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE); @@ -93,7 +95,11 @@ char *BN_bn2dec(const BIGNUM *a) i = 0; while (!BN_is_zero(t)) { *lp = BN_div_word(t, BN_DEC_CONV); + if (*lp == (BN_ULONG)-1) + goto err; lp++; + if (lp - bn_data >= bn_data_num) + goto err; } lp--; /* |