From 99719bb0c281e3a8aac07b881ab8eaf53a270988 Mon Sep 17 00:00:00 2001 From: Christophe JAILLET Date: Sat, 25 Nov 2023 13:05:04 +0100 Subject: [PATCH] kdb: Fix a potential buffer overflow in kdb_local() [ Upstream commit 4f41d30cd6dc865c3cbc1a852372321eba6d4e4c ] 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 Signed-off-by: Sasha Levin --- kernel/debug/kdb/kdb_main.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 438b868..35aa2e9 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -1349,8 +1349,6 @@ 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 -- 2.7.4