pam_kwallet/0001-Several-cleanups.patch

From a6369519e080b741fea731ab42bb19e84c6e6fdb Mon Sep 17 00:00:00 2001
From: Fabian Vogt <fabian@ritter-vogt.de>
Date: Thu, 3 Aug 2017 09:02:14 +0200
Subject: [PATCH 1/3] Several cleanups

- No cppcheck warnings anymore
- Use snprintf everywhere
- Avoid pointless multiplication with sizeof(char)
- Avoid memory leaks
---
 pam_kwallet.c | 44 ++++++++++++++++++++++++++++++++------------
 1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/pam_kwallet.c b/pam_kwallet.c
index d88c5e0..cba57e7 100644
--- a/pam_kwallet.c
+++ b/pam_kwallet.c
@@ -151,13 +151,14 @@ static int set_env(pam_handle_t *pamh, const char *name, const char *value)
         //We do not return because pam_putenv might work
     }
 
-    char *pamEnv = malloc(strlen(name) + strlen(value) + 2); //2 is for = and \0
+    size_t pamEnvSize = strlen(name) + strlen(value) + 2; //2 is for = and \0
+    char *pamEnv = malloc(pamEnvSize);
     if (!pamEnv) {
         pam_syslog(pamh, LOG_WARNING, "%s: Impossible to allocate memory for pamEnv", logPrefix);
         return -1;
     }
 
-    sprintf (pamEnv, "%s=%s", name, value);
+    snprintf (pamEnv, pamEnvSize, "%s=%s", name, value);
     int ret = pam_putenv(pamh, pamEnv);
     free(pamEnv);
 
@@ -240,6 +241,11 @@ cleanup:
     return result;
 }
 
+static void cleanup_free(pam_handle_t *pamh, void *ptr, int error_status)
+{
+    free(ptr);
+}
+
 PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
 {
     pam_syslog(pamh, LOG_INFO, "%s: pam_sm_authenticate\n", logPrefix);
@@ -297,14 +303,17 @@ PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, cons
         return PAM_IGNORE;
     }
 
-    char *key = malloc(sizeof(char) * KWALLET_PAM_KEYSIZE);
-    if (kwallet_hash(password, userInfo, key) != 0) {
+    char *key = malloc(KWALLET_PAM_KEYSIZE);
+    if (!key || kwallet_hash(password, userInfo, key) != 0) {
+        free(key);
         pam_syslog(pamh, LOG_ERR, "%s: Fail into creating the hash", logPrefix);
         return PAM_IGNORE;
     }
 
-    result = pam_set_data(pamh, kwalletPamDataKey, key, NULL);
+    result = pam_set_data(pamh, kwalletPamDataKey, key, cleanup_free);
+
     if (result != PAM_SUCCESS) {
+        free(key);
         pam_syslog(pamh, LOG_ERR, "%s: Impossible to store the hashed password: %s", logPrefix
             , pam_strerror(pamh, result));
         return PAM_IGNORE;
@@ -385,9 +394,8 @@ cleanup:
 static int better_write(int fd, const char *buffer, int len)
 {
     size_t writtenBytes = 0;
-    int result;
     while(writtenBytes < len) {
-        result = write(fd, buffer + writtenBytes, len - writtenBytes);
+        int result = write(fd, buffer + writtenBytes, len - writtenBytes);
         if (result < 0) {
             if (errno != EAGAIN && errno != EINTR) {
                 return -1;
@@ -450,6 +458,7 @@ static void start_kwallet(pam_handle_t *pamh, struct passwd *userInfo, const cha
     if (result != PAM_SUCCESS) {
         pam_syslog(pamh, LOG_ERR, "%s: Impossible to set %s env, %s",
                    logPrefix, envVar, pam_strerror(pamh, result));
+        free(fullSocket);
         return;
     }
 
@@ -459,12 +468,15 @@ static void start_kwallet(pam_handle_t *pamh, struct passwd *userInfo, const cha
     if (strlen(fullSocket) > sizeof(local.sun_path)) {
         pam_syslog(pamh, LOG_ERR, "%s: socket path %s too long to open",
                    logPrefix, fullSocket);
+        free(fullSocket);
         return;
     }
     strcpy(local.sun_path, fullSocket);
+    free(fullSocket);
+    fullSocket = NULL;
     unlink(local.sun_path);//Just in case it exists from a previous login
 
-    pam_syslog(pamh, LOG_INFO, "%s: final socket path: %s", logPrefix, fullSocket);
+    pam_syslog(pamh, LOG_INFO, "%s: final socket path: %s", logPrefix, local.sun_path);
 
     size_t len = strlen(local.sun_path) + sizeof(local.sun_family);
     if (bind(envSocket, (struct sockaddr *)&local, len) == -1) {
@@ -477,7 +489,7 @@ static void start_kwallet(pam_handle_t *pamh, struct passwd *userInfo, const cha
         return;
     }
 
-    if (chown(fullSocket, userInfo->pw_uid, userInfo->pw_gid) == -1) {
+    if (chown(local.sun_path, userInfo->pw_uid, userInfo->pw_gid) == -1) {
         pam_syslog(pamh, LOG_INFO, "%s: Couldn't change ownership of the socket", logPrefix);
         return;
     }
@@ -655,7 +667,8 @@ int kwallet_hash(const char *passphrase, struct passwd *userInfo, char *key)
 #else
     char *fixpath = "share/apps/kwallet/kdewallet.salt";
 #endif
-    char *path = (char*) malloc(strlen(userInfo->pw_dir) + strlen(kdehome) + strlen(fixpath) + 3);//3 == / and \0
+    size_t pathSize = strlen(userInfo->pw_dir) + strlen(kdehome) + strlen(fixpath) + 3;//3 == /, / and \0
+    char *path = (char*) malloc(pathSize);
     sprintf(path, "%s/%s/%s", userInfo->pw_dir, kdehome, fixpath);
 
     struct stat info;
@@ -666,21 +679,26 @@ int kwallet_hash(const char *passphrase, struct passwd *userInfo, char *key)
         FILE *fd = fopen(path, "r");
         if (fd == NULL) {
             syslog(LOG_ERR, "%s: Couldn't open file: %s because: %d-%s", logPrefix, path, errno, strerror(errno));
+            free(path);
             return 1;
         }
-        salt = (char*) malloc(sizeof(char) * KWALLET_PAM_SALTSIZE);
+        salt = (char*) malloc(KWALLET_PAM_SALTSIZE);
         memset(salt, '\0', KWALLET_PAM_SALTSIZE);
         fread(salt, KWALLET_PAM_SALTSIZE, 1, fd);
         fclose(fd);
     }
+    free(path);
+
     if (salt == NULL) {
         syslog(LOG_ERR, "%s-kwalletd: Couldn't create or read the salt file", logPrefix);
         return 1;
     }
 
     gcry_error_t error;
+
     error = gcry_control(GCRYCTL_INIT_SECMEM, 32768, 0);
     if (error != 0) {
+        free(salt);
         syslog(LOG_ERR, "%s-kwalletd: Can't get secure memory: %d", logPrefix, error);
         return 1;
     }
@@ -691,5 +709,7 @@ int kwallet_hash(const char *passphrase, struct passwd *userInfo, char *key)
                             GCRY_KDF_PBKDF2, GCRY_MD_SHA512,
                             salt, KWALLET_PAM_SALTSIZE,
                             KWALLET_PAM_ITERATIONS,KWALLET_PAM_KEYSIZE, key);
-    return 0;
+
+    free(salt);
+    return (int) error; // gcry_kdf_derive returns 0 on success
 }
-- 
2.13.2