mmc: Fix incorrect handling of 'read' & 'write' commands

If a malformed 'read' or 'write' command is issued, the Sandbox U-Boot
can crash because the command-handling code does no error checking on
the number of provided arguments.

This change makes the mmc 'erase', 'read' and 'write' commands only
function if the proper number of arguments are supplied.

Also puts the else assignment at the beginning fo the if() statement
to shortens the generated code.  This removes an unnecessary jump from
the generated code.

Signed-off-by: Taylor Hutt <thutt@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Andy Fleming <afleming@freescale.com>

diff --git a/common/cmd_mmc.c b/common/cmd_mmc.c
index 4c19df727a98bf2d29ea63530f8b207b6f1bff7d..7dacd5114ce1416bf1cb5c9af5589cd62530becd 100644 (file)
--- a/common/cmd_mmc.c
+++ b/common/cmd_mmc.c
@@ -250,14 +250,13 @@ static int do_mmcops(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
                return 0;
        }
 
-       if (strcmp(argv[1], "read") == 0)
+       state = MMC_INVALID;
+       if (argc == 5 && strcmp(argv[1], "read") == 0)
                state = MMC_READ;
-       else if (strcmp(argv[1], "write") == 0)
+       else if (argc == 5 && strcmp(argv[1], "write") == 0)
                state = MMC_WRITE;
-       else if (strcmp(argv[1], "erase") == 0)
+       else if (argc == 4 && strcmp(argv[1], "erase") == 0)
                state = MMC_ERASE;
-       else
-               state = MMC_INVALID;
 
        if (state != MMC_INVALID) {
                struct mmc *mmc = find_mmc_device(curr_device);