Currently when the current line should be removed from the display kdb_read() uses memset() to fill a temporary buffer with spaces. The problem is not that this could be trivially implemented using a format string rather than open coding it. The real problem is that it is possible, on systems with a long kdb_prompt_str, to write past the end of the tmpbuffer.
Happily, as mentioned above, this can be trivially implemented using a format string. Make it so!
Cc: stable@vger.kernel.org Reviewed-by: Douglas Anderson dianders@chromium.org Tested-by: Justin Stitt justinstitt@google.com Signed-off-by: Daniel Thompson daniel.thompson@linaro.org --- kernel/debug/kdb/kdb_io.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index a73779529803f..2aeaf9765b248 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -318,11 +318,9 @@ static char *kdb_read(char *buffer, size_t bufsize) break; case 14: /* Down */ case 16: /* Up */ - memset(tmpbuffer, ' ', - strlen(kdb_prompt_str) + (lastchar-buffer)); - *(tmpbuffer+strlen(kdb_prompt_str) + - (lastchar-buffer)) = '\0'; - kdb_printf("\r%s\r", tmpbuffer); + kdb_printf("\r%*c\r", + (int)(strlen(kdb_prompt_str) + (lastchar - buffer)), + ' '); *lastchar = (char)key; *(lastchar+1) = '\0'; return lastchar;