[PATCH] cmd: sf: prevent overwriting the reserved memory

[Prasad Kummari]

Added LMB API to prevent SF command from overwriting reserved
memory areas. The current SPI code does not use LMB APIs for
loading data into memory addresses. To resolve this, LMB APIs
were added to check the load address of an SF command and ensure it
does not overwrite reserved memory addresses. Similar checks are
used in TFTP, serial load, and boot code to prevent overwriting
reserved memory.

Signed-off-by: Prasad Kummari <prasad.kummari at amd.com>
---
UT:
Tested on Versal NET board

Versal NET> sf read 0xf000000 0x0 0x100                                         
device 0 offset 0x0, size 0x100                                                 
ERROR: trying to overwrite reserved memory...
                                   
Versal NET> sf read 0x79ea9000 0x 0x100                                         
device 0 offset 0x0, size 0x100                                                 
ERROR: trying to overwrite reserved memory...       
                            
Versal NET> sf write 0x79ea9000 0x 0x100                                        
device 0 offset 0x0, size 0x100                                                 
ERROR: trying to overwrite reserved memory...

Versal NET> sf write 0x79eaf000 0x20000 0x100 
device 0 offset 0x20000, size 0x100
ERROR: trying to overwrite reserved memory...

 cmd/sf.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/cmd/sf.c b/cmd/sf.c
index f43a2e08b3..d2ce1af8a0 100644
--- a/cmd/sf.c
+++ b/cmd/sf.c
@@ -10,6 +10,7 @@
 #include <div64.h>
 #include <dm.h>
 #include <log.h>
+#include <lmb.h>
 #include <malloc.h>
 #include <mapmem.h>
 #include <spi.h>
@@ -272,6 +273,35 @@ static int spi_flash_update(struct spi_flash *flash, u32 offset,
 	return 0;
 }
 
+#ifdef CONFIG_LMB
+static int do_spi_read_lmb_check(ulong start_addr, loff_t len)
+{
+	struct lmb lmb;
+	phys_size_t max_size;
+	ulong end_addr;
+
+	lmb_init_and_reserve(&lmb, gd->bd, (void *)gd->fdt_blob);
+	lmb_dump_all(&lmb);
+
+	max_size = lmb_get_free_size(&lmb, start_addr);
+	if (!max_size) {
+		printf("ERROR: trying to overwrite reserved memory...\n");
+		return CMD_RET_FAILURE;
+	}
+
+	end_addr = start_addr + max_size;
+	if (!end_addr)
+		end_addr = ULONG_MAX;
+
+	if ((start_addr + len) > end_addr) {
+		printf("ERROR: trying to overwrite reserved memory...\n");
+		return CMD_RET_FAILURE;
+	}
+
+	return 0;
+}
+#endif
+
 static int do_spi_flash_read_write(int argc, char *const argv[])
 {
 	unsigned long addr;
@@ -315,7 +345,13 @@ static int do_spi_flash_read_write(int argc, char *const argv[])
 		ret = spi_flash_update(flash, offset, len, buf);
 	} else if (strncmp(argv[0], "read", 4) == 0 ||
 			strncmp(argv[0], "write", 5) == 0) {
-		int read;
+		int read, ret;
+
+#ifdef CONFIG_LMB
+		ret = do_spi_read_lmb_check(addr, len);
+		if (ret)
+			return ret;
+#endif
 
 		read = strncmp(argv[0], "read", 4) == 0;
 		if (read)
-- 
2.25.1