[PATCH 5/5] Src/utils: fix memory leaks in mailstat()

[Kamil Dudka <kdudka@redhat.com>]

Detected by Coverity Analysis:

Error: RESOURCE_LEAK (CWE-772):
zsh-5.5.1/Src/utils.c:7406: alloc_fn: Storage is returned from allocation function "appstr".
zsh-5.5.1/Src/string.c:200:5: alloc_fn: Storage is returned from allocation function "realloc".
zsh-5.5.1/Src/string.c:200:5: identity_transfer: Passing "realloc(base, strlen(base) + strlen(append) + 1UL)" as argument 1 to function "strcat", which returns that argument.
zsh-5.5.1/Src/string.c:200:5: return_alloc_fn: Directly returning storage allocated by "strcat".
zsh-5.5.1/Src/utils.c:7406: var_assign: Assigning: "dir" = storage returned from "appstr(ztrdup(path), "/cur")".
zsh-5.5.1/Src/utils.c:7407: noescape: Resource "dir" is not freed or pointed-to in "stat".
zsh-5.5.1/Src/utils.c:7407: leaked_storage: Variable "dir" going out of scope leaks the storage it points to.
7405|          /* See if cur/ is present */
7406|          dir = appstr(ztrdup(path), "/cur");
7407|->        if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
7408|          st_ret.st_atime = st_tmp.st_atime;
7409|

Error: RESOURCE_LEAK (CWE-772):
zsh-5.5.1/Src/utils.c:7412: alloc_fn: Storage is returned from allocation function "appstr".
zsh-5.5.1/Src/string.c:200:5: alloc_fn: Storage is returned from allocation function "realloc".
zsh-5.5.1/Src/string.c:200:5: identity_transfer: Passing "realloc(base, strlen(base) + strlen(append) + 1UL)" as argument 1 to function "strcat", which returns that argument.
zsh-5.5.1/Src/string.c:200:5: return_alloc_fn: Directly returning storage allocated by "strcat".
zsh-5.5.1/Src/utils.c:7412: var_assign: Assigning: "dir" = storage returned from "appstr(dir, "/tmp")".
zsh-5.5.1/Src/utils.c:7413: noescape: Resource "dir" is not freed or pointed-to in "stat".
zsh-5.5.1/Src/utils.c:7413: leaked_storage: Variable "dir" going out of scope leaks the storage it points to.
7411|          dir[plen] = 0;
7412|          dir = appstr(dir, "/tmp");
7413|->        if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
7414|          st_ret.st_mtime = st_tmp.st_mtime;
7415|

Error: RESOURCE_LEAK (CWE-772):
zsh-5.5.1/Src/utils.c:7418: alloc_fn: Storage is returned from allocation function "appstr".
zsh-5.5.1/Src/string.c:200:5: alloc_fn: Storage is returned from allocation function "realloc".
zsh-5.5.1/Src/string.c:200:5: identity_transfer: Passing "realloc(base, strlen(base) + strlen(append) + 1UL)" as argument 1 to function "strcat", which returns that argument.
zsh-5.5.1/Src/string.c:200:5: return_alloc_fn: Directly returning storage allocated by "strcat".
zsh-5.5.1/Src/utils.c:7418: var_assign: Assigning: "dir" = storage returned from "appstr(dir, "/new")".
zsh-5.5.1/Src/utils.c:7419: noescape: Resource "dir" is not freed or pointed-to in "stat".
zsh-5.5.1/Src/utils.c:7419: leaked_storage: Variable "dir" going out of scope leaks the storage it points to.
7417|          dir[plen] = 0;
7418|          dir = appstr(dir, "/new");
7419|->        if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
7420|          st_ret.st_mtime = st_tmp.st_mtime;
7421|
---
 Src/utils.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/Src/utils.c b/Src/utils.c
index 914e30c5c..e43a3cdb4 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -7459,19 +7459,28 @@ mailstat(char *path, struct stat *st)
 
        /* See if cur/ is present */
        dir = appstr(ztrdup(path), "/cur");
-       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
+       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) {
+	   zsfree(dir);
+	   return 0;
+       }
        st_ret.st_atime = st_tmp.st_atime;
 
        /* See if tmp/ is present */
        dir[plen] = 0;
        dir = appstr(dir, "/tmp");
-       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
+       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) {
+	   zsfree(dir);
+	   return 0;
+       }
        st_ret.st_mtime = st_tmp.st_mtime;
 
        /* And new/ */
        dir[plen] = 0;
        dir = appstr(dir, "/new");
-       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) return 0;
+       if (stat(dir, &st_tmp) || !S_ISDIR(st_tmp.st_mode)) {
+	   zsfree(dir);
+	   return 0;
+       }
        st_ret.st_mtime = st_tmp.st_mtime;
 
 #if THERE_IS_EXACTLY_ONE_MAILDIR_IN_MAILPATH
@@ -7483,6 +7492,7 @@ mailstat(char *path, struct stat *st)
            st_tmp.st_atime == st_new_last.st_atime &&
            st_tmp.st_mtime == st_new_last.st_mtime) {
 	   *st = st_ret_last;
+	   zsfree(dir);
 	   return 0;
        }
        st_new_last = st_tmp;
-- 
2.17.2