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Avoid using sprintf(), vsprintf(), strcat(), and strncat().

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It is less error-prone to use functions with a return value that
indicates when truncation ocurred.
This commit is contained in:
Todd C. Miller
2020-03-11 19:46:07 -06:00
parent 1015b493b0
commit a23048bbb2
2 changed files with 11 additions and 21 deletions
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22
plugins/python/regress/iohelpers.c
View File

@@ -141,31 +141,23 @@ char *
str_replaced(const char *source, size_t dest_len, const char *old, const char *new) str_replaced(const char *source, size_t dest_len, const char *old, const char *new)
{ {
char *result = calloc(1, dest_len); char *result = calloc(1, dest_len);
char *dest = result;
char *pos = NULL; char *pos = NULL;
size_t old_len = strlen(old); size_t old_len = strlen(old);
size_t new_len = strlen(new);
size_t available_len = dest_len;
while ((pos = strstr(source, old)) != NULL) { while ((pos = strstr(source, old)) != NULL) {
size_t skipped_len = (size_t)(pos - source); size_t len = snprintf(dest, dest_len,
if (available_len <= skipped_len + 1) "%.*s%s", (int)(pos - source), source, new);
if (len >= dest_len)
goto fail; goto fail;
available_len -= skipped_len; dest_len -= len;
strncat(result, source, skipped_len); dest += len;
if (available_len <= new_len + 1)
goto fail;
available_len -= new_len;
strcat(result, new);
source = pos + old_len; source = pos + old_len;
} }
if (available_len <= strlen(source) + 1) if (strlcpy(dest, source, dest_len) >= dest_len)
goto fail; goto fail;
strcat(result, source);
return result; return result;

10
plugins/python/regress/testhelpers.c
View File

@@ -44,12 +44,11 @@ const char *
expected_path(const char *format, ...) expected_path(const char *format, ...)
{ {
static char expected_output_file[PATH_MAX]; static char expected_output_file[PATH_MAX];
int count = snprintf(expected_output_file, PATH_MAX, TESTDATA_DIR); size_t dirlen = strlcpy(expected_output_file, TESTDATA_DIR, sizeof(expected_output_file));
char *filename = expected_output_file + count;
va_list args; va_list args;
va_start(args, format); va_start(args, format);
vsprintf(filename, format, args); vsnprintf(expected_output_file + dirlen, PATH_MAX - dirlen, format, args);
va_end(args); va_end(args);
return expected_output_file; return expected_output_file;
@@ -213,10 +212,9 @@ verify_log_lines(const char *reference_path)
char *line_end = strstr(line_data, " object at "); // this skips checking the pointer hex char *line_end = strstr(line_data, " object at "); // this skips checking the pointer hex
if (line_end) if (line_end)
sprintf(line_end, " object>\n"); snprintf(line_end, sizeof(line) - (line_end - line), " object>\n");
VERIFY_TRUE(strlen(stored_str) + strlen(line_data) + 1 < sizeof(stored_str)); // we have enough space in buffer VERIFY_TRUE(strlcat(stored_str, line_data, sizeof(stored_str)) < sizeof(stored_str)); // we have enough space in buffer
strcat(stored_str, line_data);
} }
clean_output(stored_str); clean_output(stored_str);