[PATCH v2 2/4] libsepol/mls: Do not destroy context on memory error

[Vit Mojzis <vmojzis@xxxxxxxxxx>]

In case of malloc error, ctx1, or ctx2 may be pointing to uninitialized
space and context_destroy should not be used on it.

Fixes:
Error: UNINIT (CWE-457):
libsepol-3.7/src/mls.c:673:2: alloc_fn: Calling "malloc" which returns uninitialized memory.
libsepol-3.7/src/mls.c:673:2: assign: Assigning: "ctx1" = "malloc(64UL)", which points to uninitialized data.
libsepol-3.7/src/mls.c:699:2: uninit_use_in_call: Using uninitialized value "ctx1->range.level[0].cat.node" when calling "context_destroy".
 \#  697|   	ERR(handle, "could not check if mls context %s contains %s",
 \#  698|   	    mls1, mls2);
 \#  699|-> 	context_destroy(ctx1);
 \#  700|   	context_destroy(ctx2);
 \#  701|   	free(ctx1);

Error: UNINIT (CWE-457):
libsepol-3.7/src/mls.c:674:2: alloc_fn: Calling "malloc" which returns uninitialized memory.
libsepol-3.7/src/mls.c:674:2: assign: Assigning: "ctx2" = "malloc(64UL)", which points to uninitialized data.
libsepol-3.7/src/mls.c:700:2: uninit_use_in_call: Using uninitialized value "ctx2->range.level[0].cat.node" when calling "context_destroy".
 \#  698|   	    mls1, mls2);
 \#  699|   	context_destroy(ctx1);
 \#  700|-> 	context_destroy(ctx2);
 \#  701|   	free(ctx1);
 \#  702|   	free(ctx2);

Signed-off-by: Vit Mojzis <vmojzis@xxxxxxxxxx>
---
 libsepol/src/mls.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libsepol/src/mls.c b/libsepol/src/mls.c
index 45db8920..a37405d1 100644
--- a/libsepol/src/mls.c
+++ b/libsepol/src/mls.c
@@ -672,8 +672,10 @@ int sepol_mls_contains(sepol_handle_t * handle,
 	context_struct_t *ctx1 = NULL, *ctx2 = NULL;
 	ctx1 = malloc(sizeof(context_struct_t));
 	ctx2 = malloc(sizeof(context_struct_t));
-	if (ctx1 == NULL || ctx2 == NULL)
+	if (ctx1 == NULL || ctx2 == NULL){
+		ERR(handle, "out of memory");
 		goto omem;
+	}
 	context_init(ctx1);
 	context_init(ctx2);
 
@@ -690,16 +692,14 @@ int sepol_mls_contains(sepol_handle_t * handle,
 	free(ctx2);
 	return STATUS_SUCCESS;
 
-      omem:
-	ERR(handle, "out of memory");
-
       err:
-	ERR(handle, "could not check if mls context %s contains %s",
-	    mls1, mls2);
 	context_destroy(ctx1);
 	context_destroy(ctx2);
+      omem:
 	free(ctx1);
 	free(ctx2);
+	ERR(handle, "could not check if mls context %s contains %s",
+	    mls1, mls2);
 	return STATUS_ERR;
 }
 
-- 
2.47.0