efi_loader: return NULL from device path functions

For the construction of device paths we need to call the
AllocatePool service. We should not ignore if it fails due to an
out of memory situation.

This patch changes the device path functions to return NULL if
the memory allocation fails.

Additional patches will be needed to fix the callers.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

include/efi_loader.h

@@ -304,9 +304,9 @@ struct efi_device_path *efi_dp_from_eth(void);
 struct efi_device_path *efi_dp_from_mem(uint32_t mem_type,
 					uint64_t start_address,
 					uint64_t end_address);
-void efi_dp_split_file_path(struct efi_device_path *full_path,
-			    struct efi_device_path **device_path,
-			    struct efi_device_path **file_path);
+efi_status_t efi_dp_split_file_path(struct efi_device_path *full_path,
+				    struct efi_device_path **device_path,
+				    struct efi_device_path **file_path);
 
 #define EFI_DP_TYPE(_dp, _type, _subtype) \
 	(((_dp)->type == DEVICE_PATH_TYPE_##_type) && \

lib/efi_loader/efi_device_path.c

@@ -58,8 +58,11 @@ static void *dp_alloc(size_t sz)
 {
 	void *buf;
 
-	if (efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, sz, &buf) != EFI_SUCCESS)
+	if (efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, sz, &buf) !=
+	    EFI_SUCCESS) {
+		debug("EFI: ERROR: out of memory in %s\n", __func__);
 		return NULL;
+	}
 
 	return buf;
 }
@@ -227,6 +230,8 @@ struct efi_device_path *efi_dp_dup(const struct efi_device_path *dp)
 		return NULL;
 
 	ndp = dp_alloc(sz);
+	if (!ndp)
+		return NULL;
 	memcpy(ndp, dp, sz);
 
 	return ndp;
@@ -246,6 +251,8 @@ struct efi_device_path *efi_dp_append(const struct efi_device_path *dp1,
 		unsigned sz1 = efi_dp_size(dp1);
 		unsigned sz2 = efi_dp_size(dp2);
 		void *p = dp_alloc(sz1 + sz2 + sizeof(END));
+		if (!p)
+			return NULL;
 		memcpy(p, dp1, sz1);
 		memcpy(p + sz1, dp2, sz2);
 		memcpy(p + sz1 + sz2, &END, sizeof(END));
@@ -267,6 +274,8 @@ struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 	} else if (!dp) {
 		unsigned sz = node->length;
 		void *p = dp_alloc(sz + sizeof(END));
+		if (!p)
+			return NULL;
 		memcpy(p, node, sz);
 		memcpy(p + sz, &END, sizeof(END));
 		ret = p;
@@ -274,6 +283,8 @@ struct efi_device_path *efi_dp_append_node(const struct efi_device_path *dp,
 		/* both dp and node are non-null */
 		unsigned sz = efi_dp_size(dp);
 		void *p = dp_alloc(sz + node->length + sizeof(END));
+		if (!p)
+			return NULL;
 		memcpy(p, dp, sz);
 		memcpy(p + sz, node, node->length);
 		memcpy(p + sz + node->length, &END, sizeof(END));
@@ -435,6 +446,8 @@ struct efi_device_path *efi_dp_from_dev(struct udevice *dev)
 	void *buf, *start;
 
 	start = buf = dp_alloc(dp_size(dev) + sizeof(END));
+	if (!buf)
+		return NULL;
 	buf = dp_fill(buf, dev);
 	*((struct efi_device_path *)buf) = END;
 
@@ -576,6 +589,8 @@ struct efi_device_path *efi_dp_from_part(struct blk_desc *desc, int part)
 	void *buf, *start;
 
 	start = buf = dp_alloc(dp_part_size(desc, part) + sizeof(END));
+	if (!buf)
+		return NULL;
 
 	buf = dp_part_fill(buf, desc, part);
 
@@ -614,6 +629,8 @@ struct efi_device_path *efi_dp_from_file(struct blk_desc *desc, int part,
 	dpsize += fpsize;
 
 	start = buf = dp_alloc(dpsize + sizeof(END));
+	if (!buf)
+		return NULL;
 
 	if (desc)
 		buf = dp_part_fill(buf, desc, part);
@@ -648,6 +665,8 @@ struct efi_device_path *efi_dp_from_eth(void)
 	dpsize += sizeof(*ndp);
 
 	start = buf = dp_alloc(dpsize + sizeof(END));
+	if (!buf)
+		return NULL;
 
 #ifdef CONFIG_DM_ETH
 	buf = dp_fill(buf, eth_get_dev());
@@ -678,6 +697,8 @@ struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
 	void *buf, *start;
 
 	start = buf = dp_alloc(sizeof(*mdp) + sizeof(END));
+	if (!buf)
+		return NULL;
 
 	mdp = buf;
 	mdp->dp.type = DEVICE_PATH_TYPE_HARDWARE_DEVICE;
@@ -697,22 +718,31 @@ struct efi_device_path *efi_dp_from_mem(uint32_t memory_type,
  * Helper to split a full device path (containing both device and file
  * parts) into it's constituent parts.
  */
-void efi_dp_split_file_path(struct efi_device_path *full_path,
-			    struct efi_device_path **device_path,
-			    struct efi_device_path **file_path)
+efi_status_t efi_dp_split_file_path(struct efi_device_path *full_path,
+				    struct efi_device_path **device_path,
+				    struct efi_device_path **file_path)
 {
 	struct efi_device_path *p, *dp, *fp;
 
+	*device_path = NULL;
+	*file_path = NULL;
 	dp = efi_dp_dup(full_path);
+	if (!dp)
+		return EFI_OUT_OF_RESOURCES;
 	p = dp;
-	while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH))
+	while (!EFI_DP_TYPE(p, MEDIA_DEVICE, FILE_PATH)) {
 		p = efi_dp_next(p);
+		if (!p)
+			return EFI_OUT_OF_RESOURCES;
+	}
 	fp = efi_dp_dup(p);
-
+	if (!fp)
+		return EFI_OUT_OF_RESOURCES;
 	p->type = DEVICE_PATH_TYPE_END;
 	p->sub_type = DEVICE_PATH_SUB_TYPE_END;
 	p->length = sizeof(*p);
 
 	*device_path = dp;
 	*file_path = fp;
+	return EFI_SUCCESS;
 }