crypto: Clear temporary stack buffers after use

This reduces possibility of exposure of private keys should something
get access to stack memory.

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/crypto/md5.c b/src/crypto/md5.c
index db2b8cc..f64dfd3 100644 (file)
--- a/src/crypto/md5.c
+++ b/src/crypto/md5.c
@@ -30,6 +30,7 @@ int hmac_md5_vector(const u8 *key, size_t key_len, size_t num_elem,
        u8 tk[16];
        const u8 *_addr[6];
        size_t i, _len[6];
+       int res;
 
        if (num_elem > 5) {
                /*
@@ -85,7 +86,10 @@ int hmac_md5_vector(const u8 *key, size_t key_len, size_t num_elem,
        _len[0] = 64;
        _addr[1] = mac;
        _len[1] = MD5_MAC_LEN;
-       return md5_vector(2, _addr, _len, mac);
+       res = md5_vector(2, _addr, _len, mac);
+       os_memset(k_pad, 0, sizeof(k_pad));
+       os_memset(tk, 0, sizeof(tk));
+       return res;
 }
 
 

diff --git a/src/crypto/sha1-prf.c b/src/crypto/sha1-prf.c
index 90b9e74..4b2d137 100644 (file)
--- a/src/crypto/sha1-prf.c
+++ b/src/crypto/sha1-prf.c
@@ -61,6 +61,7 @@ int sha1_prf(const u8 *key, size_t key_len, const char *label,
                }
                counter++;
        }
+       os_memset(hash, 0, sizeof(hash));
 
        return 0;
 }

diff --git a/src/crypto/sha1.c b/src/crypto/sha1.c
index d48c77d..8fce139 100644 (file)
--- a/src/crypto/sha1.c
+++ b/src/crypto/sha1.c
@@ -30,6 +30,7 @@ int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
        unsigned char tk[20];
        const u8 *_addr[6];
        size_t _len[6], i;
+       int ret;
 
        if (num_elem > 5) {
                /*
@@ -84,7 +85,9 @@ int hmac_sha1_vector(const u8 *key, size_t key_len, size_t num_elem,
        _len[0] = 64;
        _addr[1] = mac;
        _len[1] = SHA1_MAC_LEN;
-       return sha1_vector(2, _addr, _len, mac);
+       ret = sha1_vector(2, _addr, _len, mac);
+       os_memset(k_pad, 0, sizeof(k_pad));
+       return ret;
 }
 
 

diff --git a/src/crypto/sha256-prf.c b/src/crypto/sha256-prf.c
index 9a11208..79791c0 100644 (file)
--- a/src/crypto/sha256-prf.c
+++ b/src/crypto/sha256-prf.c
@@ -95,4 +95,6 @@ void sha256_prf_bits(const u8 *key, size_t key_len, const char *label,
                u8 mask = 0xff << (8 - buf_len_bits % 8);
                buf[pos - 1] &= mask;
        }
+
+       os_memset(hash, 0, sizeof(hash));
 }