[PATCH 1/2] tftp: rework the logic to validate the load address

[Sughosh Ganu]

Use the lmb_read_check() function to verify if it is safe to use a
region of memory to load data from a tftp command. The current logic
checks the amount of free memory available, starting from the 'load
address'. This call fails if the same region of memory has been used
earlier. This used to work earlier as the LMB memory map had a local
scope and was not persistent. Fix this issue by using the
lmb_read_check() call instead which only returns an error in case the
memory region has been marked for not allowing re-use.

Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---

Note: To be applied on next, on top of
https://patchwork.ozlabs.org/project/uboot/patch/20240913073251.2286529-2-prasad.kummari@amd.com/

 net/tftp.c | 19 +------------------
 1 file changed, 1 insertion(+), 18 deletions(-)

diff --git a/net/tftp.c b/net/tftp.c
index b5d227d8bc..d6744bc24e 100644
--- a/net/tftp.c
+++ b/net/tftp.c
@@ -82,7 +82,6 @@ static ulong	tftp_block_wrap;
 static ulong	tftp_block_wrap_offset;
 static int	tftp_state;
 static ulong	tftp_load_addr;
-static ulong	tftp_load_size;
 #ifdef CONFIG_TFTP_TSIZE
 /* The file size reported by the server */
 static int	tftp_tsize;
@@ -159,13 +158,8 @@ static inline int store_block(int block, uchar *src, unsigned int len)
 	void *ptr;
 
 	if (CONFIG_IS_ENABLED(LMB)) {
-		ulong end_addr = tftp_load_addr + tftp_load_size;
-
-		if (!end_addr)
-			end_addr = ULONG_MAX;
-
 		if (store_addr < tftp_load_addr ||
-		    store_addr + len > end_addr) {
+		    lmb_read_check(store_addr, len)) {
 			puts("\nTFTP error: ");
 			puts("trying to overwrite reserved memory...\n");
 			return -1;
@@ -712,19 +706,8 @@ static void tftp_timeout_handler(void)
 	}
 }
 
-/* Initialize tftp_load_addr and tftp_load_size from image_load_addr and lmb */
 static int tftp_init_load_addr(void)
 {
-	if (CONFIG_IS_ENABLED(LMB)) {
-		phys_size_t max_size;
-
-		max_size = lmb_get_free_size(image_load_addr);
-		if (!max_size)
-			return -1;
-
-		tftp_load_size = max_size;
-	}
-
 	tftp_load_addr = image_load_addr;
 	return 0;
 }
-- 
2.34.1