Legacy NET tftp invokes a store_block() function which performs buffer
validation (LMB, address wrapping). Do the same with NET_LWIP.
Signed-off-by: Jerome Forissier <jerome.foriss...@linaro.org>
Suggested-by: Sughosh Ganu <sughosh.g...@linaro.org>
---
Changes in v3:
- store_block() [tftp]: add Sphinx-like documentation
net/lwip/tftp.c | 56 +++++++++++++++++++++++++++++++++++++++----------
1 file changed, 45 insertions(+), 11 deletions(-)
diff --git a/net/lwip/tftp.c b/net/lwip/tftp.c
index 123d66b5dba..c7f1420ca0f 100644
--- a/net/lwip/tftp.c
+++ b/net/lwip/tftp.c
@@ -8,6 +8,7 @@
#include <efi_loader.h>
#include <image.h>
#include <linux/delay.h>
+#include <linux/kconfig.h>
#include <lwip/apps/tftp_client.h>
#include <lwip/timeouts.h>
#include <mapmem.h>
@@ -31,6 +32,47 @@ struct tftp_ctx {
enum done_state done;
};
+/**
+ * store_block() - copy received data
+ *
+ * This function is called by the receive callback to copy a block of data
+ * into its final location (ctx->daddr). Before doing so, it checks if the copy
+ * is allowed.
+ *
+ * @ctx: the context for the current transfer
+ * @src: the data received from the TCP stack
+ * @len: the length of the data
+ */
+static int store_block(struct tftp_ctx *ctx, void *src, u16_t len)
+{
+ ulong store_addr = ctx->daddr;
+ void *ptr;
+
+ if (CONFIG_IS_ENABLED(LMB)) {
+ if (store_addr + len < store_addr ||
+ lmb_read_check(store_addr, len)) {
+ puts("\nTFTP error: ");
+ puts("trying to overwrite reserved memory...\n");
+ return -1;
+ }
+ }
+
+ ptr = map_sysmem(store_addr, len);
+ memcpy(ptr, src, len);
+ unmap_sysmem(ptr);
+
+ ctx->daddr += len;
+ ctx->size += len;
+ ctx->block_count++;
+ if (ctx->block_count % 10 == 0) {
+ putc('#');
+ if (ctx->block_count % (65 * 10) == 0)
+ puts("\n\t ");
+ }
+
+ return 0;
+}
+
static void *tftp_open(const char *fname, const char *mode, u8_t is_write)
{
return NULL;
@@ -71,17 +113,9 @@ static int tftp_write(void *handle, struct pbuf *p)
struct tftp_ctx *ctx = handle;
struct pbuf *q;
- for (q = p; q; q = q->next) {
- memcpy((void *)ctx->daddr, q->payload, q->len);
- ctx->daddr += q->len;
- ctx->size += q->len;
- ctx->block_count++;
- if (ctx->block_count % 10 == 0) {
- putc('#');
- if (ctx->block_count % (65 * 10) == 0)
- puts("\n\t ");
- }
- }
+ for (q = p; q; q = q->next)
+ if (store_block(ctx, q->payload, q->len) < 0)
+ return -1;
return 0;
}
--
2.43.0
