This is a note to let you know that I've just added the patch titled ACPI: battery: Fix missing NUL-termination with large strings to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: acpi-battery-fix-missing-nul-termination-with-large-.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 328ce2a1ea67787afec923cc7918f85ef88a36eb Author: Armin Wolf <W_Armin@xxxxxx> Date: Sat Jan 14 09:50:50 2023 +0100 ACPI: battery: Fix missing NUL-termination with large strings [ Upstream commit f2ac14b5f197e4a2dec51e5ceaa56682ff1592bc ] When encountering a string bigger than the destination buffer (32 bytes), the string is not properly NUL-terminated, causing buffer overreads later. This for example happens on the Inspiron 3505, where the battery model name is larger than 32 bytes, which leads to sysfs showing the model name together with the serial number string (which is NUL-terminated and thus prevents worse). Fix this by using strscpy() which ensures that the result is always NUL-terminated. Fixes: 106449e870b3 ("ACPI: Battery: Allow extract string from integer") Signed-off-by: Armin Wolf <W_Armin@xxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c index 974c2df13da1d..a49a09e3de1b3 100644 --- a/drivers/acpi/battery.c +++ b/drivers/acpi/battery.c @@ -465,7 +465,7 @@ static int extract_package(struct acpi_battery *battery, u8 *ptr = (u8 *)battery + offsets[i].offset; if (element->type == ACPI_TYPE_STRING || element->type == ACPI_TYPE_BUFFER) - strncpy(ptr, element->string.pointer, 32); + strscpy(ptr, element->string.pointer, 32); else if (element->type == ACPI_TYPE_INTEGER) { strncpy(ptr, (u8 *)&element->integer.value, sizeof(u64));