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SubjectRE: [PATCH, net-next] net: ethernet: freescale: fix false-positive string overflow warning
Date
From: Arnd Bergmann <arnd@arndb.de> Sent: 2018年5月28日 23:50
> While compile-testing on arm64 with gcc-8.1, I ran into a build diagnostic:
>
> drivers/net/ethernet/freescale/fec_main.c: In function 'fec_probe':
> drivers/net/ethernet/freescale/fec_main.c:3517:25: error: '%d' directive
> writing between 1 and 10 bytes into a region of size 5
> [-Werror=format-overflow=]
> sprintf(irq_name, "int%d", i);
> ^~
> drivers/net/ethernet/freescale/fec_main.c:3517:21: note: directive
> argument in the range [0, 2147483646]
> sprintf(irq_name, "int%d", i);
> ^~~~~~~
> drivers/net/ethernet/freescale/fec_main.c:3517:3: note: 'sprintf' output
> between 5 and 14 bytes into a destination of size 8
> sprintf(irq_name, "int%d", i);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> It appears this has never shown on ppc32 or arm32 for an unknown
> reason, but now gcc fails to identify that the 'irq_cnt' loop index has an
> upper bound of 3, and instead uses a bogus range.
>
> To work around the warning, this changes the sprintf to snprintf with the
> correct buffer length.
>
> Fixes: 78cc6e7ef957 ("net: ethernet: freescale: Allow FEC with
> COMPILE_TEST")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Fugang Duan <fugang.duan@nxp.com>

> ---
> drivers/net/ethernet/freescale/fec_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> b/drivers/net/ethernet/freescale/fec_main.c
> index ab7521c04eb2..c729665107f5 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -3514,7 +3514,7 @@ fec_probe(struct platform_device *pdev)
> goto failed_init;
>
> for (i = 0; i < irq_cnt; i++) {
> - sprintf(irq_name, "int%d", i);
> + snprintf(irq_name, sizeof(irq_name), "int%d", i);
> irq = platform_get_irq_byname(pdev, irq_name);
> if (irq < 0)
> irq = platform_get_irq(pdev, i);
> --
> 2.9.0

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