samba-o3: fix -Werror=maybe-uninitialized in lib/mscat/mscat_pks7.c

samba-o3 test failed in ubuntu:1804 image with:

    ../../lib/mscat/mscat_pkcs7.c: In function ‘mscat_pkcs7_import_catfile’:
    ../../lib/mscat/mscat_pkcs7.c:143:18: error: ‘blob.length’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
      mscat_data.size = blob.length;
      ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~
    ../../lib/mscat/mscat_pkcs7.c:142:18: error: ‘blob.data’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
      mscat_data.data = blob.data;
      ~~~~~~~~~~~~~~~~^~~~~~~~~~~
    ../../lib/mscat/mscat_pkcs7.c: In function ‘mscat_pkcs7_verify’:
    ../../lib/mscat/mscat_pkcs7.c:225:16: error: ‘blob.length’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
       ca_data.size = blob.length;
       ~~~~~~~~~~~~~^~~~~~~~~~~~~
    ../../lib/mscat/mscat_pkcs7.c:224:16: error: ‘blob.data’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
       ca_data.data = blob.data;
       ~~~~~~~~~~~~~^~~~~~~~~~~
    cc1: all warnings being treated as errors

Since in `mscat_read_file`, it may still return rc = 0 while goto error,
ends up with blob uninitialized.

Signed-off-by: Joe Guo <joeg@catalyst.net.nz>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/mscat/mscat_pkcs7.c b/lib/mscat/mscat_pkcs7.c
index d606a86f095..5d882891313 100644
--- a/lib/mscat/mscat_pkcs7.c
+++ b/lib/mscat/mscat_pkcs7.c
@@ -66,7 +66,7 @@ static int mscat_read_file(TALLOC_CTX *mem_ctx,
 	struct stat sb = {0};
 	size_t alloc_size;
 	size_t count;
-	DATA_BLOB blob;
+	DATA_BLOB blob = data_blob_null;
 	FILE *fp;
 	int rc;
 
@@ -82,22 +82,26 @@ static int mscat_read_file(TALLOC_CTX *mem_ctx,
 
 	if (!S_ISREG(sb.st_mode)) {
 		errno = EINVAL;
+		rc = -1;
 		goto error;
 	}
 	if (SIZE_MAX - 1 < (unsigned long)sb.st_size) {
 		errno = ENOMEM;
+		rc = -1;
 		goto error;
 	}
 	alloc_size = sb.st_size + 1;
 
 	blob = data_blob_talloc_zero(mem_ctx, alloc_size);
 	if (blob.data == NULL) {
+		rc = -1;
 		goto error;
 	}
 
 	count = fread(blob.data, 1, blob.length, fp);
 	if (count != blob.length) {
 		if (ferror(fp)) {
+			rc = -1;
 			goto error;
 		}
 	}