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wolfsshd: fix uninitialized fileNames[] deref in HandleInclude #1029

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wolfsshd: fix uninitialized fileNames[] deref in HandleInclude #1029

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36 changes: 31 additions & 5 deletions apps/wolfsshd/configuration.c
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Original file line number Diff line number Diff line change
Expand Up @@ -723,7 +723,7 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value, int depth)

if (ret == WS_SUCCESS) {
if (!WOPENDIR(NULL, conf->heap, &d, path)) {
word32 fileCount = 0, i, j;
word32 fileCount = 0, fileFilled = 0, i, j;
char** fileNames = NULL;

/* Count up the number of files */
Expand All @@ -749,6 +749,12 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value, int depth)
if (fileNames == NULL) {
ret = WS_MEMORY_E;
}
else {
/* Zero so any slot not filled by the second pass
* (e.g. files removed from the directory between
* the two passes) is NULL rather than garbage. */
WMEMSET(fileNames, 0, fileCount * sizeof(char*));
}
}

if (ret == WS_SUCCESS) {
Expand All @@ -764,21 +770,33 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value, int depth)
if (dir->d_type != DT_DIR)
#endif
{
/* Duplicate the name; readdir() may reuse its
* dirent storage on the next call, so the
* pointer cannot be retained across the loop. */
char* nameCopy = WSTRDUP(dir->d_name, conf->heap,
DYNTYPE_PATH);
if (nameCopy == NULL) {
ret = WS_MEMORY_E;
break;
}
/* Insert in string order */
for (j = 0; j < i; j++) {
if (WSTRCMP(dir->d_name, fileNames[j])
< 0) {
if (WSTRCMP(nameCopy, fileNames[j]) < 0) {
WMEMMOVE(fileNames+j+1, fileNames+j,
(i - j)*sizeof(char*));
break;
}
}
fileNames[j] = dir->d_name;
fileNames[j] = nameCopy;
i++;
}
}
/* Only process slots actually filled by the second
* pass; the directory may have shrunk since the
* count pass. */
fileFilled = i;

for (i = 0; i < fileCount; i++) {
for (i = 0; ret == WS_SUCCESS && i < fileFilled; i++) {
/* Check if filename prefix matches */
if (prefixLen > 0) {
if ((int)WSTRLEN(fileNames[i]) <= prefixLen) {
Expand Down Expand Up @@ -817,6 +835,14 @@ static int HandleInclude(WOLFSSHD_CONFIG *conf, const char *value, int depth)
}
}

/* Free the duplicated names. fileFilled counts the
* slots actually populated, so every entry below it
* holds a valid pointer. */
for (i = 0; i < fileFilled; i++) {
if (fileNames[i] != NULL) {
WFREE(fileNames[i], conf->heap, DYNTYPE_PATH);
}
}
if (fileNames != NULL) {
WFREE(fileNames, conf->heap, DYNTYPE_PATH);
}
Expand Down
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