1 files changed, 32 insertions, 14 deletions

diff --git a/drivers/net/can/softing/softing_fw.c b/drivers/net/can/softing/softing_fw.c
index 721df91cdbfb..282570daf3ef 100644
--- a/drivers/net/can/softing/softing_fw.c
+++ b/drivers/net/can/softing/softing_fw.c
@@ -91,12 +91,12 @@ int softing_bootloader_command(struct softing *card, int16_t cmd,
 	return ret;
 }
 
-static int fw_parse(const uint8_t **pmem, uint16_t *ptype, uint32_t *paddr,
-		uint16_t *plen, const uint8_t **pdat)
+static int fw_parse(const u8 **pmem, const u8 *limit, u16 *ptype,
+		    u32 *paddr, u16 *plen, const u8 **pdat)
 {
 	uint16_t checksum[2];
-	const uint8_t *mem;
-	const uint8_t *end;
+	const u8 *mem;
+	const u8 *record_end;
 
 	/*
 	 * firmware records are a binary, unaligned stream composed of:
@@ -114,14 +114,21 @@ static int fw_parse(const uint8_t **pmem, uint16_t *ptype, uint32_t *paddr,
 	 * endianness & alignment.
 	 */
 	mem = *pmem;
+	/* A record needs an 8-byte prefix and a 2-byte checksum. */
+	if (mem > limit || limit - mem < 10)
+		return -EINVAL;
+
 	*ptype = le16_to_cpup((void *)&mem[0]);
 	*paddr = le32_to_cpup((void *)&mem[2]);
 	*plen = le16_to_cpup((void *)&mem[6]);
+	if (*plen > limit - mem - 10)
+		return -EINVAL;
+
 	*pdat = &mem[8];
 	/* verify checksum */
-	end = &mem[8 + *plen];
-	checksum[0] = le16_to_cpup((void *)end);
-	for (checksum[1] = 0; mem < end; ++mem)
+	record_end = &mem[8 + *plen];
+	checksum[0] = le16_to_cpup((void *)record_end);
+	for (checksum[1] = 0; mem < record_end; ++mem)
 		checksum[1] += *mem;
 	if (checksum[0] != checksum[1])
 		return -EINVAL;
@@ -139,6 +146,7 @@ int softing_load_fw(const char *file, struct softing *card,
 	uint16_t type, len;
 	uint32_t addr;
 	uint8_t *buf = NULL, *new_buf;
+	s64 dpram_offset;
 	int buflen = 0;
 	int8_t type_end = 0;
 
@@ -153,7 +161,7 @@ int softing_load_fw(const char *file, struct softing *card,
 	mem = fw->data;
 	end = &mem[fw->size];
 	/* look for header record */
-	ret = fw_parse(&mem, &type, &addr, &len, &dat);
+	ret = fw_parse(&mem, end, &type, &addr, &len, &dat);
 	if (ret < 0)
 		goto failed;
 	if (type != 0xffff)
@@ -164,7 +172,7 @@ int softing_load_fw(const char *file, struct softing *card,
 	}
 	/* ok, we had a header */
 	while (mem < end) {
-		ret = fw_parse(&mem, &type, &addr, &len, &dat);
+		ret = fw_parse(&mem, end, &type, &addr, &len, &dat);
 		if (ret < 0)
 			goto failed;
 		if (type == 3) {
@@ -179,9 +187,13 @@ int softing_load_fw(const char *file, struct softing *card,
 			goto failed;
 		}
 
-		if ((addr + len + offset) > size)
+		dpram_offset = (s64)addr + offset;
+		if (dpram_offset < 0 || dpram_offset > size ||
+		    len > size - dpram_offset) {
+			ret = -EINVAL;
 			goto failed;
-		memcpy_toio(&dpram[addr + offset], dat, len);
+		}
+		memcpy_toio(&dpram[dpram_offset], dat, len);
 		/* be sure to flush caches from IO space */
 		mb();
 		if (len > buflen) {
@@ -195,7 +207,7 @@ int softing_load_fw(const char *file, struct softing *card,
 			buf = new_buf;
 		}
 		/* verify record data */
-		memcpy_fromio(buf, &dpram[addr + offset], len);
+		memcpy_fromio(buf, &dpram[dpram_offset], len);
 		if (memcmp(buf, dat, len)) {
 			/* is not ok */
 			dev_alert(&card->pdev->dev, "DPRAM readback failed\n");
@@ -237,7 +249,7 @@ int softing_load_app_fw(const char *file, struct softing *card)
 	mem = fw->data;
 	end = &mem[fw->size];
 	/* look for header record */
-	ret = fw_parse(&mem, &type, &addr, &len, &dat);
+	ret = fw_parse(&mem, end, &type, &addr, &len, &dat);
 	if (ret)
 		goto failed;
 	ret = -EINVAL;
@@ -253,7 +265,7 @@ int softing_load_app_fw(const char *file, struct softing *card)
 	}
 	/* ok, we had a header */
 	while (mem < end) {
-		ret = fw_parse(&mem, &type, &addr, &len, &dat);
+		ret = fw_parse(&mem, end, &type, &addr, &len, &dat);
 		if (ret)
 			goto failed;
 
@@ -279,6 +291,12 @@ int softing_load_app_fw(const char *file, struct softing *card)
 		/* work in 16bit (target) */
 		sum &= 0xffff;
 
+		if (card->pdat->app.offs > card->dpram_size ||
+		    len > card->dpram_size - card->pdat->app.offs) {
+			ret = -EINVAL;
+			goto failed;
+		}
+
 		memcpy_toio(&card->dpram[card->pdat->app.offs], dat, len);
 		iowrite32(card->pdat->app.offs + card->pdat->app.addr,
 				&card->dpram[DPRAM_COMMAND + 2]);