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authorDaniel Thompson <daniel.thompson@linaro.org>2024-04-24 17:03:38 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-06-16 14:47:44 +0300
commitea303a7af85b2cb67585dcefd9895bd1c52696b1 (patch)
treefbdd337043a497bdf15460a1c03a778dc3bc9684
parente00ec562b0e0dbc85a1788a7aec578932a462857 (diff)
downloadlinux-ea303a7af85b2cb67585dcefd9895bd1c52696b1.tar.xz
kdb: Use format-specifiers rather than memset() for padding in kdb_read()
commit c9b51ddb66b1d96e4d364c088da0f1dfb004c574 upstream. 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> Link: https://lore.kernel.org/r/20240424-kgdb_read_refactor-v3-5-f236dbe9828d@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--kernel/debug/kdb/kdb_io.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index a73779529803..2aeaf9765b24 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -318,11 +318,9 @@ poll_again:
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;