commit 49e8f47505a64f46981e3caa8c167594ae6936ff Author: David Goulet dgoulet@torproject.org Date: Mon Jun 20 13:47:19 2016 -0400

util: zero target buffer of base*_encode/decode

Make sure to memset(0) the destination buffer so we don't leave any uninitialized data.

Fixes #19462

Signed-off-by: David Goulet dgoulet@torproject.org --- src/common/util_format.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/common/util_format.c b/src/common/util_format.c index 009db7b..9009e1a 100644 --- a/src/common/util_format.c +++ b/src/common/util_format.c @@ -46,6 +46,9 @@ base32_encode(char *dest, size_t destlen, const char *src, size_t srclen) tor_assert(base32_encoded_size(srclen) <= destlen); tor_assert(destlen < SIZE_T_CEILING);

+ /* Make sure we leave no uninitialized data in the destination buffer. */ + memset(dest, 0, destlen); + for (i=0,bit=0; bit < nbits; ++i, bit+=5) { /* set v to the 16-bit value starting at src[bits/8], 0-padded. */ v = ((uint8_t)src[bit/8]) << 8; @@ -75,6 +78,7 @@ 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);

+ /* Make sure we leave no uninitialized data in the destination buffer. */ memset(dest, 0, destlen);

/* Convert base32 encoded chars to the 5-bit values that they represent. */ @@ -197,7 +201,8 @@ base64_encode(char *dest, size_t destlen, const char *src, size_t srclen, if (enclen > INT_MAX) return -1;

- memset(dest, 0, enclen); + /* Make sure we leave no uninitialized data in the destination buffer. */ + memset(dest, 0, destlen);

/* XXX/Yawning: If this ends up being too slow, this can be sped up * by separating the multiline format case and the normal case, and @@ -398,6 +403,7 @@ base64_decode(char *dest, size_t destlen, const char *src, size_t srclen) if (destlen > SIZE_T_CEILING) return -1;

+ /* Make sure we leave no uninitialized data in the destination buffer. */ memset(dest, 0, destlen);

/* Iterate over all the bytes in src. Each one will add 0 or 6 bits to the @@ -472,6 +478,9 @@ base16_encode(char *dest, size_t destlen, const char *src, size_t srclen) tor_assert(destlen >= srclen*2+1); tor_assert(destlen < SIZE_T_CEILING);

+ /* Make sure we leave no uninitialized data in the destination buffer. */ + memset(dest, 0, destlen); + cp = dest; end = src+srclen; while (src<end) { @@ -532,6 +541,7 @@ base16_decode(char *dest, size_t destlen, const char *src, size_t srclen) if (destlen < srclen/2 || destlen > INT_MAX) return -1;

+ /* Make sure we leave no uninitialized data in the destination buffer. */ memset(dest, 0, destlen);

end = src+srclen;