y4m_input_fetch_frame: fix ubsan null/zero offset warning
reported under clang-13; use a while loop in file_read() to force a size
check before attempting to read. buf (aux_buf) may be may be null when
no conversion is necessary.
y4minput.c:29:43: runtime error: applying zero offset to null pointer
Bug: b/229626362
Change-Id: Ia3250d6ff9c325faf48eaa31f4399e20837f8f7b
(cherry picked from commit 4a8de4215225b6ee2840e21231d42f063795ca5a)
diff --git a/common/y4minput.c b/common/y4minput.c
index a1dca10..f76b7d5 100644
--- a/common/y4minput.c
+++ b/common/y4minput.c
@@ -21,12 +21,13 @@
// Reads 'size' bytes from 'file' into 'buf' with some fault tolerance.
// Returns true on success.
static int file_read(void *buf, size_t size, FILE *file) {
- const int kMaxRetries = 5;
- int retry_count = 0;
- int file_error;
+ const int kMaxTries = 5;
+ int try_count = 0;
+ int file_error = 0;
size_t len = 0;
- do {
+ while (!feof(file) && len < size && try_count < kMaxTries) {
const size_t n = fread((uint8_t *)buf + len, 1, size - len, file);
+ ++try_count;
len += n;
file_error = ferror(file);
if (file_error) {
@@ -39,13 +40,13 @@
return 0;
}
}
- } while (!feof(file) && len < size && ++retry_count < kMaxRetries);
+ }
if (!feof(file) && len != size) {
fprintf(stderr,
"Error reading file: %u of %u bytes read,"
- " error: %d, retries: %d, %d: %s\n",
- (uint32_t)len, (uint32_t)size, file_error, retry_count, errno,
+ " error: %d, tries: %d, %d: %s\n",
+ (uint32_t)len, (uint32_t)size, file_error, try_count, errno,
strerror(errno));
}
return len == size;