From: Christophe JAILLET Date: Sat, 25 Nov 2023 12:05:04 +0000 (+0100) Subject: kdb: Fix a potential buffer overflow in kdb_local() X-Git-Tag: v6.8-rc1~32^2 X-Git-Url: https://repo.jachan.dev/linux.git/commitdiff_plain/4f41d30cd6dc865c3cbc1a852372321eba6d4e4c kdb: Fix a potential buffer overflow in kdb_local() When appending "[defcmd]" to 'kdb_prompt_str', the size of the string already in the buffer should be taken into account. An option could be to switch from strncat() to strlcat() which does the correct test to avoid such an overflow. However, this actually looks as dead code, because 'defcmd_in_progress' can't be true here. See a more detailed explanation at [1]. [1]: https://lore.kernel.org/all/CAD=FV=WSh7wKN7Yp-3wWiDgX4E3isQ8uh0LCzTmd1v9Cg9j+nQ@mail.gmail.com/ Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Signed-off-by: Christophe JAILLET Reviewed-by: Douglas Anderson --- diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 6b213c8252d6..d05066cb40b2 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -1348,8 +1348,6 @@ do_full_getstr: /* PROMPT can only be set if we have MEM_READ permission. */ snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"), raw_smp_processor_id()); - if (defcmd_in_progress) - strncat(kdb_prompt_str, "[defcmd]", CMD_BUFLEN); /* * Fetch command from keyboard