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authorJon Simons <jon@jonsimons.org>2014-01-15 13:50:15 -0800
committerAndreas Schneider <asn@cryptomilk.org>2014-01-16 09:27:41 +0100
commit6007c3c43f7256698ed7ed62d13a588ee355daee (patch)
tree15ae3d45d0b88c77011e6e08791504fbb33d6e9a /src/bind.c
parent9d1ddd0547452f44ad9c5517c0e1e095e1a1f4e7 (diff)
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bind: fix possible double-frees in ssh_bind_free
Make sure to explicitly set key pointers to NULL following the use of 'ssh_key_free' throughout bind.c. Before this change, a double free can happen via 'ssh_bind_free' as in this example callpath: // create an ssh_bind ssh_bind b = ssh_bind_new(); // provide a path to a wrong key-type ssh_bind_options_set(b, SSH_BIND_OPTIONS_DSAKEY, path_to_rsa_key); // initialize set key-type ssh_bind_listen(b); -> error path "The DSA host key has the wrong type: %d", ssh_key_free(sshbind->dsa) -> ssh_key_clean(key) // OK -> SAFE_FREE(key) // OK, but, sshbind->dsa is *not* set to NULL // ssh_bind_listen failed, so clean up ssh_bind ssh_bind_free(b); -> ssh_key_free(sshbind->dsa) // double-free here To fix, set pointers to NULL that have been free'd with 'ssh_key_free'. Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Diffstat (limited to 'src/bind.c')
-rw-r--r--src/bind.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/src/bind.c b/src/bind.c
index c8306da3..698b9533 100644
--- a/src/bind.c
+++ b/src/bind.c
@@ -179,6 +179,7 @@ int ssh_bind_listen(ssh_bind sshbind) {
ssh_set_error(sshbind, SSH_FATAL,
"The ECDSA host key has the wrong type");
ssh_key_free(sshbind->ecdsa);
+ sshbind->ecdsa = NULL;
return SSH_ERROR;
}
}
@@ -201,6 +202,7 @@ int ssh_bind_listen(ssh_bind sshbind) {
"The DSA host key has the wrong type: %d",
ssh_key_type(sshbind->dsa));
ssh_key_free(sshbind->dsa);
+ sshbind->dsa = NULL;
return SSH_ERROR;
}
}
@@ -222,6 +224,7 @@ int ssh_bind_listen(ssh_bind sshbind) {
ssh_set_error(sshbind, SSH_FATAL,
"The RSA host key has the wrong type");
ssh_key_free(sshbind->rsa);
+ sshbind->rsa = NULL;
return SSH_ERROR;
}
}
@@ -235,7 +238,9 @@ int ssh_bind_listen(ssh_bind sshbind) {
fd = bind_socket(sshbind, host, sshbind->bindport);
if (fd == SSH_INVALID_SOCKET) {
ssh_key_free(sshbind->dsa);
+ sshbind->dsa = NULL;
ssh_key_free(sshbind->rsa);
+ sshbind->rsa = NULL;
return -1;
}
sshbind->bindfd = fd;
@@ -246,7 +251,9 @@ int ssh_bind_listen(ssh_bind sshbind) {
fd, strerror(errno));
close(fd);
ssh_key_free(sshbind->dsa);
+ sshbind->dsa = NULL;
ssh_key_free(sshbind->rsa);
+ sshbind->rsa = NULL;
return -1;
}
} else {
@@ -348,8 +355,11 @@ void ssh_bind_free(ssh_bind sshbind){
SAFE_FREE(sshbind->ecdsakey);
ssh_key_free(sshbind->dsa);
+ sshbind->dsa = NULL;
ssh_key_free(sshbind->rsa);
+ sshbind->rsa = NULL;
ssh_key_free(sshbind->ecdsa);
+ sshbind->ecdsa = NULL;
for (i = 0; i < 10; i++) {
if (sshbind->wanted_methods[i]) {