From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-187.mta1.migadu.com (out-187.mta1.migadu.com [95.215.58.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EE31311C14 for ; Tue, 19 Aug 2025 09:59:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755597592; cv=none; b=TihaQY4wq5rtq0v96N9CPQaVgFJylLdPf00OLHK2RpgHbE4D/W1IK9m44gzzDI5M9FX2CoP2pTTZvfKtUW3iGt5FJbdWHkNW19TA1fF+7czkep4RRpZoKy61JvzdLx/Uh6livdZPQBHT02RXephd1iI6xk8v3GA2Bt2F5iB4rh4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755597592; c=relaxed/simple; bh=bqXFZLZv8TYeMB0kUtgvPvy1BXOCfoE0cc6WZwtPcZU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hJqd1U4Ze5O+ywPlnb0TSjg6/ZWC6f2q7xg67NPO/fFQkJ7FQI7/0iie1y/XSyeAKpZhncuGlvrWxtU4iGj9Nxkc44KMvanrv+62xAXJ5OdRn493X8RMbesZu1TEq3jOD7P2p8NR6f+Bfu/zfhOQfBV8tSF8pRIkcUAejoR5cBQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ggGxeLq7; arc=none smtp.client-ip=95.215.58.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ggGxeLq7" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1755597588; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zPBPoszorfQb+WmqrsH8eN2n08yL5TCak5Kl/DltLUE=; b=ggGxeLq7hUwFNbCu2Pb2WC5kNL2bIPd8NkuemVG4VzzoGDnggLnZlPLGC0qCdubZziCRGx SVKV2BcCwL/T03uQ3ulg/MY67sjE/f2TC0rQgzyNvCj1puHHS3iWEB2vlxGuuHXFo3Q9Es yK8F7ykf/a290ub6zSlvCt9SNpb0tGo= From: Thorsten Blum To: Jason Wessel , Daniel Thompson , Douglas Anderson , Justin Stitt , Thorsten Blum , Martin Hicks Cc: linux-hardening@vger.kernel.org, Daniel Thompson , kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/4] kdb: Replace deprecated strcpy() with memmove() in vkdb_printf() Date: Tue, 19 Aug 2025 11:59:04 +0200 Message-ID: <20250819095915.711085-2-thorsten.blum@linux.dev> In-Reply-To: <20250819095915.711085-1-thorsten.blum@linux.dev> References: <20250819095915.711085-1-thorsten.blum@linux.dev> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT strcpy() is deprecated and its behavior is undefined when the source and destination buffers overlap. Use memmove() instead to avoid any undefined behavior. Adjust comments for clarity. Link: https://github.com/KSPP/linux/issues/88 Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Reviewed-by: Douglas Anderson Signed-off-by: Thorsten Blum --- kernel/debug/kdb/kdb_io.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 9b11b10b120c..b12b9db75c1d 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -714,8 +714,8 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) * it, depending on the results of the search. */ cp++; /* to byte after the newline */ - replaced_byte = *cp; /* remember what/where it was */ - cphold = cp; + replaced_byte = *cp; /* remember what it was */ + cphold = cp; /* remember where it was */ *cp = '\0'; /* end the string for our search */ /* @@ -732,8 +732,9 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) * Shift the buffer left. */ *cphold = replaced_byte; - strcpy(kdb_buffer, cphold); - len = strlen(kdb_buffer); + len = strlen(cphold); + /* Use memmove() because the buffers overlap */ + memmove(kdb_buffer, cphold, len + 1); next_avail = kdb_buffer + len; size_avail = sizeof(kdb_buffer) - len; goto kdb_print_out; @@ -872,8 +873,9 @@ int vkdb_printf(enum kdb_msgsrc src, const char *fmt, va_list ap) */ if (kdb_grepping_flag && !suspend_grep) { *cphold = replaced_byte; - strcpy(kdb_buffer, cphold); - len = strlen(kdb_buffer); + len = strlen(cphold); + /* Use memmove() because the buffers overlap */ + memmove(kdb_buffer, cphold, len + 1); next_avail = kdb_buffer + len; size_avail = sizeof(kdb_buffer) - len; } -- 2.50.1