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Commit d5661f46 authored by Christophe JAILLET's avatar Christophe JAILLET Committed by Greg Kroah-Hartman
Browse files

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: 5d5314d6 ("kdb: core for kgdb back end (1 of 2)")
Signed-off-by: default avatarChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent cf6260a3

kernel/debug/kdb/kdb_main.c

+0 −2
Original line number Diff line number Diff line
@@ -1365,8 +1365,6 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs, 
		/* 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