commit 47760c7ba5f1c87c945f4a018e3b3da6d127a8b9 Author: Nick Mathewson nickm@torproject.org Date: Mon Dec 22 12:56:35 2014 -0500

When decoding a base-{16,32,64} value, clear the target buffer first

This is a good idea in case the caller stupidly doesn't check the return value from baseX_decode(), and as a workaround for the current inconsistent API of base16_decode.

Prevents any fallout from bug 14013. --- src/common/crypto.c | 6 ++++++ src/common/util.c | 3 +++ 2 files changed, 9 insertions(+)

diff --git a/src/common/crypto.c b/src/common/crypto.c index 925beb3..6327614 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -2678,6 +2678,8 @@ base64_decode(char *dest, size_t destlen, const char *src, size_t srclen) if (destlen > SIZE_T_CEILING) return -1;

+ memset(dest, 0, destlen); + EVP_DecodeInit(&ctx); EVP_DecodeUpdate(&ctx, (unsigned char*)dest, &len, (unsigned char*)src, srclen); @@ -2699,6 +2701,8 @@ base64_decode(char *dest, size_t destlen, const char *src, size_t srclen) if (destlen > SIZE_T_CEILING) return -1;

+ memset(dest, 0, destlen); + /* Iterate over all the bytes in src. Each one will add 0 or 6 bits to the * value we're decoding. Accumulate bits in <b>n</b>, and whenever we have * 24 bits, batch them into 3 bytes and flush those bytes to dest. @@ -2878,6 +2882,8 @@ base32_decode(char *dest, size_t destlen, const char *src, size_t srclen) tor_assert((nbits/8) <= destlen); /* We need enough space. */ tor_assert(destlen < SIZE_T_CEILING);

+ memset(dest, 0, destlen); + /* Convert base32 encoded chars to the 5-bit values that they represent. */ tmp = tor_malloc_zero(srclen); for (j = 0; j < srclen; ++j) { diff --git a/src/common/util.c b/src/common/util.c index 5eb0f9a..036fd25 100644 --- a/src/common/util.c +++ b/src/common/util.c @@ -1076,6 +1076,9 @@ base16_decode(char *dest, size_t destlen, const char *src, size_t srclen) return -1; if (destlen < srclen/2 || destlen > SIZE_T_CEILING) return -1; + + memset(dest, 0, destlen); + end = src+srclen; while (src<end) { v1 = hex_decode_digit_(*src);