[PATCH] netxen: validate unified ROM directory bounds

[Pengpeng Hou <pengpeng@iscas.ac.cn>]

The unified ROM parser walks directory and data descriptor tables from
the firmware file. The existing checks compute table and data limits with
base + count * size or base + size before comparing with the firmware
size. Those calculations use fields from the firmware image and can wrap
before the comparison.

Add range helpers that validate tables and entries with division and
subtraction instead of overflowing additions. Pass the firmware size into
the directory lookup helper, validate each directory entry before reading
its type field, and validate bootloader, firmware and product-table
entries before their descriptor fields are used.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
 .../ethernet/qlogic/netxen/netxen_nic_init.c  | 148 +++++++++++-------
 1 file changed, 90 insertions(+), 58 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c b/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c
index 8bc4e2b69569..5722c55fa0cc 100644
--- a/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c
+++ b/drivers/net/ethernet/qlogic/netxen/netxen_nic_init.c
@@ -561,20 +561,55 @@ int netxen_pinit_from_rom(struct netxen_adapter *adapter)
 	return 0;
 }
 
-static struct uni_table_desc *nx_get_table_desc(const u8 *unirom, int section)
+#define NX_UNI_DIR_TYPE_OFF		8
+#define NX_UNI_DIR_ENTRY_MIN_SIZE \
+	((NX_UNI_DIR_TYPE_OFF + 1) * sizeof(u32))
+#define NX_UNI_PRODUCT_ENTRY_MIN_SIZE \
+	((NX_UNI_FIRMWARE_IDX_OFF + 1) * sizeof(u32))
+
+static bool netxen_rom_range_valid(size_t size, u32 off, u32 len)
+{
+	return off <= size && len <= size - off;
+}
+
+static bool netxen_rom_table_valid(size_t size, u32 off, u32 n, u32 esz)
+{
+	if (off > size)
+		return false;
+	if (!esz)
+		return n == 0;
+
+	return n <= (size - off) / esz;
+}
+
+static bool netxen_rom_entry_valid(size_t size, u32 off, u32 esz, u32 idx)
+{
+	if (!esz || off > size)
+		return false;
+
+	return idx < (size - off) / esz;
+}
+
+static struct uni_table_desc *
+nx_get_table_desc(const u8 *unirom, size_t fw_size, int section)
 {
-	uint32_t i;
 	struct uni_table_desc *directory = (struct uni_table_desc *) &unirom[0];
-	__le32 entries = cpu_to_le32(directory->num_entries);
+	u32 entries = cpu_to_le32(directory->num_entries);
+	u32 entry_size = cpu_to_le32(directory->entry_size);
+	u32 findex = cpu_to_le32(directory->findex);
+	u32 i;
 
-	for (i = 0; i < entries; i++) {
+	if (entry_size < NX_UNI_DIR_ENTRY_MIN_SIZE ||
+	    !netxen_rom_table_valid(fw_size, findex, entries, entry_size))
+		return NULL;
 
-		__le32 offs = cpu_to_le32(directory->findex) +
-				(i * cpu_to_le32(directory->entry_size));
-		__le32 tab_type = cpu_to_le32(*((u32 *)&unirom[offs] + 8));
+	for (i = 0; i < entries; i++) {
+		size_t offs = findex + (size_t)i * entry_size;
+		u32 tab_type = cpu_to_le32(*((u32 *)&unirom[offs] +
+						NX_UNI_DIR_TYPE_OFF));
 
 		if (tab_type == section)
-			return (struct uni_table_desc *) &unirom[offs];
+			return (struct uni_table_desc *)&unirom[offs];
 	}
 
 	return NULL;
@@ -586,20 +621,18 @@ static int
 netxen_nic_validate_header(struct netxen_adapter *adapter)
 {
 	const u8 *unirom = adapter->fw->data;
-	struct uni_table_desc *directory = (struct uni_table_desc *) &unirom[0];
+	struct uni_table_desc *directory = (struct uni_table_desc *)&unirom[0];
 	u32 fw_file_size = adapter->fw->size;
-	u32 tab_size;
-	__le32 entries;
-	__le32 entry_size;
+	u32 entries, entry_size, findex;
 
 	if (fw_file_size < QLCNIC_FILEHEADER_SIZE)
 		return -EINVAL;
 
 	entries = cpu_to_le32(directory->num_entries);
 	entry_size = cpu_to_le32(directory->entry_size);
-	tab_size = cpu_to_le32(directory->findex) + (entries * entry_size);
+	findex = cpu_to_le32(directory->findex);
 
-	if (fw_file_size < tab_size)
+	if (!netxen_rom_table_valid(fw_file_size, findex, entries, entry_size))
 		return -EINVAL;
 
 	return 0;
@@ -611,30 +644,30 @@ netxen_nic_validate_bootld(struct netxen_adapter *adapter)
 	struct uni_table_desc *tab_desc;
 	struct uni_data_desc *descr;
 	const u8 *unirom = adapter->fw->data;
-	__le32 idx = cpu_to_le32(*((int *)&unirom[adapter->file_prd_off] +
-				NX_UNI_BOOTLD_IDX_OFF));
-	u32 offs;
-	u32 tab_size;
-	u32 data_size;
+	u32 data_len, data_off, entry_size, findex, idx;
+	u32 section = NX_UNI_DIR_SECT_BOOTLD;
+	size_t offs;
 
-	tab_desc = nx_get_table_desc(unirom, NX_UNI_DIR_SECT_BOOTLD);
+	idx = cpu_to_le32(*((int *)&unirom[adapter->file_prd_off] +
+			     NX_UNI_BOOTLD_IDX_OFF));
+	tab_desc = nx_get_table_desc(unirom, adapter->fw->size, section);
 
 	if (!tab_desc)
 		return -EINVAL;
 
-	tab_size = cpu_to_le32(tab_desc->findex) +
-			(cpu_to_le32(tab_desc->entry_size) * (idx + 1));
-
-	if (adapter->fw->size < tab_size)
+	entry_size = cpu_to_le32(tab_desc->entry_size);
+	findex = cpu_to_le32(tab_desc->findex);
+	if (entry_size < sizeof(*descr) ||
+	    !netxen_rom_entry_valid(adapter->fw->size, findex, entry_size,
+				     idx))
 		return -EINVAL;
 
-	offs = cpu_to_le32(tab_desc->findex) +
-		(cpu_to_le32(tab_desc->entry_size) * (idx));
+	offs = findex + (size_t)entry_size * idx;
 	descr = (struct uni_data_desc *)&unirom[offs];
+	data_off = cpu_to_le32(descr->findex);
+	data_len = cpu_to_le32(descr->size);
 
-	data_size = cpu_to_le32(descr->findex) + cpu_to_le32(descr->size);
-
-	if (adapter->fw->size < data_size)
+	if (!netxen_rom_range_valid(adapter->fw->size, data_off, data_len))
 		return -EINVAL;
 
 	return 0;
@@ -646,29 +679,30 @@ netxen_nic_validate_fw(struct netxen_adapter *adapter)
 	struct uni_table_desc *tab_desc;
 	struct uni_data_desc *descr;
 	const u8 *unirom = adapter->fw->data;
-	__le32 idx = cpu_to_le32(*((int *)&unirom[adapter->file_prd_off] +
-				NX_UNI_FIRMWARE_IDX_OFF));
-	u32 offs;
-	u32 tab_size;
-	u32 data_size;
+	u32 data_len, data_off, entry_size, findex, idx;
+	u32 section = NX_UNI_DIR_SECT_FW;
+	size_t offs;
 
-	tab_desc = nx_get_table_desc(unirom, NX_UNI_DIR_SECT_FW);
+	idx = cpu_to_le32(*((int *)&unirom[adapter->file_prd_off] +
+			     NX_UNI_FIRMWARE_IDX_OFF));
+	tab_desc = nx_get_table_desc(unirom, adapter->fw->size, section);
 
 	if (!tab_desc)
 		return -EINVAL;
 
-	tab_size = cpu_to_le32(tab_desc->findex) +
-			(cpu_to_le32(tab_desc->entry_size) * (idx + 1));
-
-	if (adapter->fw->size < tab_size)
+	entry_size = cpu_to_le32(tab_desc->entry_size);
+	findex = cpu_to_le32(tab_desc->findex);
+	if (entry_size < sizeof(*descr) ||
+	    !netxen_rom_entry_valid(adapter->fw->size, findex, entry_size,
+				     idx))
 		return -EINVAL;
 
-	offs = cpu_to_le32(tab_desc->findex) +
-		(cpu_to_le32(tab_desc->entry_size) * (idx));
+	offs = findex + (size_t)entry_size * idx;
 	descr = (struct uni_data_desc *)&unirom[offs];
-	data_size = cpu_to_le32(descr->findex) + cpu_to_le32(descr->size);
+	data_off = cpu_to_le32(descr->findex);
+	data_len = cpu_to_le32(descr->size);
 
-	if (adapter->fw->size < data_size)
+	if (!netxen_rom_range_valid(adapter->fw->size, data_off, data_len))
 		return -EINVAL;
 
 	return 0;
@@ -682,39 +716,37 @@ netxen_nic_validate_product_offs(struct netxen_adapter *adapter)
 	const u8 *unirom = adapter->fw->data;
 	int mn_present = (NX_IS_REVISION_P2(adapter->ahw.revision_id)) ?
 			1 : netxen_p3_has_mn(adapter);
-	__le32 entries;
-	__le32 entry_size;
-	u32 tab_size;
-	u32 i;
+	u32 entries, entry_size, findex, i;
+	u32 section = NX_UNI_DIR_SECT_PRODUCT_TBL;
 
-	ptab_descr = nx_get_table_desc(unirom, NX_UNI_DIR_SECT_PRODUCT_TBL);
+	ptab_descr = nx_get_table_desc(unirom, adapter->fw->size, section);
 	if (ptab_descr == NULL)
 		return -EINVAL;
 
 	entries = cpu_to_le32(ptab_descr->num_entries);
 	entry_size = cpu_to_le32(ptab_descr->entry_size);
-	tab_size = cpu_to_le32(ptab_descr->findex) + (entries * entry_size);
-
-	if (adapter->fw->size < tab_size)
+	findex = cpu_to_le32(ptab_descr->findex);
+	if (entry_size < NX_UNI_PRODUCT_ENTRY_MIN_SIZE ||
+	    !netxen_rom_table_valid(adapter->fw->size, findex, entries,
+				     entry_size))
 		return -EINVAL;
 
 nomn:
 	for (i = 0; i < entries; i++) {
-
-		__le32 flags, file_chiprev, offs;
+		size_t offs;
+		__le32 flags, file_chiprev;
 		u8 chiprev = adapter->ahw.revision_id;
 		uint32_t flagbit;
 
-		offs = cpu_to_le32(ptab_descr->findex) +
-				(i * cpu_to_le32(ptab_descr->entry_size));
+		offs = findex + (size_t)i * entry_size;
 		flags = cpu_to_le32(*((int *)&unirom[offs] + NX_UNI_FLAGS_OFF));
 		file_chiprev = cpu_to_le32(*((int *)&unirom[offs] +
-							NX_UNI_CHIP_REV_OFF));
+						    NX_UNI_CHIP_REV_OFF));
 
 		flagbit = mn_present ? 1 : 2;
 
 		if ((chiprev == file_chiprev) &&
-					((1ULL << flagbit) & flags)) {
+		    ((1ULL << flagbit) & flags)) {
 			adapter->file_prd_off = offs;
 			return 0;
 		}
@@ -767,7 +799,7 @@ static struct uni_data_desc *nx_get_data_desc(struct netxen_adapter *adapter,
 	struct uni_table_desc *tab_desc;
 	__le32 offs;
 
-	tab_desc = nx_get_table_desc(unirom, section);
+	tab_desc = nx_get_table_desc(unirom, adapter->fw->size, section);
 
 	if (tab_desc == NULL)
 		return NULL;
-- 
2.43.0