cli: avoid buffer overrun

Invoking the sandbox with

    /u-boot -c ⧵0xef⧵0xbf⧵0xbd

results in a segmentation fault.

Function b_getch() retrieves a character from the input stream. This
character may be > 0x7f. If type char is signed, static_get() will
return a negative number and in parse_stream() we will use that
negative number as an index for array map[] resulting in a buffer
overflow.

Reported-by: Harry Lockyer <harry_lockyer@tutanota.com>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/common/cli_hush.c b/common/cli_hush.c
index 171069f5f49b085dd4b37a42b2c848914c208aa5..cee87249bc2cf9ba69cdb6cb157315dbca8c8bd2 100644 (file)
--- a/common/cli_hush.c
+++ b/common/cli_hush.c
@@ -324,7 +324,7 @@ typedef struct {
 /* I can almost use ordinary FILE *.  Is open_memstream() universally
  * available?  Where is it documented? */
 struct in_str {
-       const char *p;
+       const unsigned char *p;
 #ifndef __U_BOOT__
        char peek_buf[2];
 #endif