Fix an uninitialized data access

zfs_acl_node_alloc allocates an uninitialized data buffer, but upstack zfs_acl_chmod only partially initializes it. KMSAN reported that this memory remained uninitialized at the point when it was read by lzjb_compress, which suggests a possible kernel memory disclosure bug. The full KMSAN warning may be found in the PR. #16511 Signed-off-by: Alan Somers <[email protected]> Sponsored by: Axcient
openzfs · Sep 10, 2024 · 361e119 · 361e119
1 parent 17dd66d
commit 361e119
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/module/os/freebsd/zfs/zfs_acl.c b/module/os/freebsd/zfs/zfs_acl.c
@@ -473,7 +473,7 @@ zfs_acl_node_alloc(size_t bytes)
 
 	aclnode = kmem_zalloc(sizeof (zfs_acl_node_t), KM_SLEEP);
 	if (bytes) {
-		aclnode->z_acldata = kmem_alloc(bytes, KM_SLEEP);
+		aclnode->z_acldata = kmem_zalloc(bytes, KM_SLEEP);
 		aclnode->z_allocdata = aclnode->z_acldata;
 		aclnode->z_allocsize = bytes;
 		aclnode->z_size = bytes;

diff --git a/module/os/linux/zfs/zfs_acl.c b/module/os/linux/zfs/zfs_acl.c
@@ -471,7 +471,7 @@ zfs_acl_node_alloc(size_t bytes)
 
 	aclnode = kmem_zalloc(sizeof (zfs_acl_node_t), KM_SLEEP);
 	if (bytes) {
-		aclnode->z_acldata = kmem_alloc(bytes, KM_SLEEP);
+		aclnode->z_acldata = kmem_zalloc(bytes, KM_SLEEP);
 		aclnode->z_allocdata = aclnode->z_acldata;
 		aclnode->z_allocsize = bytes;
 		aclnode->z_size = bytes;