Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index a3eaf08..c2f0aa8 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -35,8 +35,8 @@
  */
 static void cgroup_bpf_release(struct work_struct *work)
 {
-	struct cgroup *cgrp = container_of(work, struct cgroup,
-					   bpf.release_work);
+	struct cgroup *p, *cgrp = container_of(work, struct cgroup,
+					       bpf.release_work);
 	enum bpf_cgroup_storage_type stype;
 	struct bpf_prog_array *old_array;
 	unsigned int type;
@@ -65,6 +65,9 @@
 
 	mutex_unlock(&cgroup_mutex);
 
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_put(p);
+
 	percpu_ref_exit(&cgrp->bpf.refcnt);
 	cgroup_put(cgrp);
 }
@@ -199,6 +202,7 @@
  */
 #define	NR ARRAY_SIZE(cgrp->bpf.effective)
 	struct bpf_prog_array *arrays[NR] = {};
+	struct cgroup *p;
 	int ret, i;
 
 	ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0,
@@ -206,6 +210,9 @@
 	if (ret)
 		return ret;
 
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_get(p);
+
 	for (i = 0; i < NR; i++)
 		INIT_LIST_HEAD(&cgrp->bpf.progs[i]);
 
@@ -221,6 +228,9 @@
 	for (i = 0; i < NR; i++)
 		bpf_prog_array_free(arrays[i]);
 
+	for (p = cgroup_parent(cgrp); p; p = cgroup_parent(p))
+		cgroup_bpf_put(p);
+
 	percpu_ref_exit(&cgrp->bpf.refcnt);
 
 	return -ENOMEM;
@@ -293,8 +303,8 @@
 {
 	struct list_head *progs = &cgrp->bpf.progs[type];
 	struct bpf_prog *old_prog = NULL;
-	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE],
-		*old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {NULL};
+	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
+	struct bpf_cgroup_storage *old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {};
 	enum bpf_cgroup_storage_type stype;
 	struct bpf_prog_list *pl;
 	bool pl_was_allocated;
@@ -956,16 +966,23 @@
 
 static int sockopt_alloc_buf(struct bpf_sockopt_kern *ctx, int max_optlen)
 {
-	if (unlikely(max_optlen > PAGE_SIZE) || max_optlen < 0)
+	if (unlikely(max_optlen < 0))
 		return -EINVAL;
 
+	if (unlikely(max_optlen > PAGE_SIZE)) {
+		/* We don't expose optvals that are greater than PAGE_SIZE
+		 * to the BPF program.
+		 */
+		max_optlen = PAGE_SIZE;
+	}
+
 	ctx->optval = kzalloc(max_optlen, GFP_USER);
 	if (!ctx->optval)
 		return -ENOMEM;
 
 	ctx->optval_end = ctx->optval + max_optlen;
 
-	return 0;
+	return max_optlen;
 }
 
 static void sockopt_free_buf(struct bpf_sockopt_kern *ctx)
@@ -999,13 +1016,13 @@
 	 */
 	max_optlen = max_t(int, 16, *optlen);
 
-	ret = sockopt_alloc_buf(&ctx, max_optlen);
-	if (ret)
-		return ret;
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
+	if (max_optlen < 0)
+		return max_optlen;
 
 	ctx.optlen = *optlen;
 
-	if (copy_from_user(ctx.optval, optval, *optlen) != 0) {
+	if (copy_from_user(ctx.optval, optval, min(*optlen, max_optlen)) != 0) {
 		ret = -EFAULT;
 		goto out;
 	}
@@ -1033,13 +1050,20 @@
 		/* export any potential modifications */
 		*level = ctx.level;
 		*optname = ctx.optname;
-		*optlen = ctx.optlen;
-		*kernel_optval = ctx.optval;
+
+		/* optlen == 0 from BPF indicates that we should
+		 * use original userspace data.
+		 */
+		if (ctx.optlen != 0) {
+			*optlen = ctx.optlen;
+			*kernel_optval = ctx.optval;
+			/* export and don't free sockopt buf */
+			return 0;
+		}
 	}
 
 out:
-	if (ret)
-		sockopt_free_buf(&ctx);
+	sockopt_free_buf(&ctx);
 	return ret;
 }
 EXPORT_SYMBOL(__cgroup_bpf_run_filter_setsockopt);
@@ -1066,12 +1090,12 @@
 	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
 		return retval;
 
-	ret = sockopt_alloc_buf(&ctx, max_optlen);
-	if (ret)
-		return ret;
-
 	ctx.optlen = max_optlen;
 
+	max_optlen = sockopt_alloc_buf(&ctx, max_optlen);
+	if (max_optlen < 0)
+		return max_optlen;
+
 	if (!retval) {
 		/* If kernel getsockopt finished successfully,
 		 * copy whatever was returned to the user back
@@ -1085,10 +1109,13 @@
 			goto out;
 		}
 
-		if (ctx.optlen > max_optlen)
-			ctx.optlen = max_optlen;
+		if (ctx.optlen < 0) {
+			ret = -EFAULT;
+			goto out;
+		}
 
-		if (copy_from_user(ctx.optval, optval, ctx.optlen) != 0) {
+		if (copy_from_user(ctx.optval, optval,
+				   min(ctx.optlen, max_optlen)) != 0) {
 			ret = -EFAULT;
 			goto out;
 		}
@@ -1104,7 +1131,7 @@
 		goto out;
 	}
 
-	if (ctx.optlen > max_optlen) {
+	if (ctx.optlen > max_optlen || ctx.optlen < 0) {
 		ret = -EFAULT;
 		goto out;
 	}
@@ -1117,10 +1144,12 @@
 		goto out;
 	}
 
-	if (copy_to_user(optval, ctx.optval, ctx.optlen) ||
-	    put_user(ctx.optlen, optlen)) {
-		ret = -EFAULT;
-		goto out;
+	if (ctx.optlen != 0) {
+		if (copy_to_user(optval, ctx.optval, ctx.optlen) ||
+		    put_user(ctx.optlen, optlen)) {
+			ret = -EFAULT;
+			goto out;
+		}
 	}
 
 	ret = ctx.retval;