apparmor: Fix aa_label_build() error handling for failed merges

aa_label_merge() can return NULL for memory allocations failures
make sure to handle and set the correct error in this case.

Reported-by: Peng Hao <peng.hao2@zte.com.cn>
Signed-off-by: John Johansen <john.johansen@canonical.com>

diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index 08c88de0ffdadcb4d68450cff103408cba3a7746..11975ec8d5665957d145ae67f31a03bb41fc77e4 100644 (file)
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -1444,7 +1444,10 @@ check:
                        new = aa_label_merge(label, target, GFP_KERNEL);
                if (IS_ERR_OR_NULL(new)) {
                        info = "failed to build target label";
-                       error = PTR_ERR(new);
+                       if (!new)
+                               error = -ENOMEM;
+                       else
+                               error = PTR_ERR(new);
                        new = NULL;
                        perms.allow = 0;
                        goto audit;