Re: [PATCH] net: stmmac: fix length of PTP clock's name string

From: Jakub Kicinski
Date: Wed Oct 09 2019 - 19:10:35 EST


On Mon, 7 Oct 2019 17:43:04 +0200, Antonio Borneo wrote:
> The field "name" in struct ptp_clock_info has a fixed size of 16
> chars and is used as zero terminated string by clock_name_show()
> in drivers/ptp/ptp_sysfs.c
> The current initialization value requires 17 chars to fit also the
> null termination, and this causes overflow to the next bytes in
> the struct when the string is read as null terminated:
> hexdump -C /sys/class/ptp/ptp0/clock_name
> 00000000 73 74 6d 6d 61 63 5f 70 74 70 5f 63 6c 6f 63 6b |stmmac_ptp_clock|
> 00000010 a0 ac b9 03 0a |.....|
> where the extra 4 bytes (excluding the newline) after the string
> represent the integer 0x03b9aca0 = 62500000 assigned to the field
> "max_adj" that follows "name" in the same struct.
>
> There is no strict requirement for the "name" content and in the
> comment in ptp_clock_kernel.h it's reported it should just be 'A
> short "friendly name" to identify the clock'.
> Replace it with "stmmac ptp".
>
> Signed-off-by: Antonio Borneo <antonio.borneo@xxxxxx>
> Fixes: 92ba6888510c ("stmmac: add the support for PTP hw clock driver")

Applied to net, queued for stable.

For future submissions please indicate the target tree. Networking fixes
should go to the net tree and have [PATCH net] in the subject, while
normal patches such as new features and clean ups should be tagged as
[PATCH net-next].