RE: [PATCH] phy: exynos5-usbdrd: Use dynamic phy_cfg size to prevent OOB access

[Alim Akhtar]

Hi Selvarasu

> -----Original Message-----
> From: Selvarasu Ganesan <selvarasu.g@xxxxxxxxxxx>
> Sent: Monday, August 31, 2026 12:33 PM
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> peter.griffin@xxxxxxxxxx; alim.akhtar@xxxxxxxxxxx;
> pritam.sutar@xxxxxxxxxxx; andre.draszik@xxxxxxxxxx; kernel@xxxxxxxxx;
> linux-phy@xxxxxxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
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> Cc: jh0801.jung@xxxxxxxxxxx; dh10.jung@xxxxxxxxxxx;
> akash.m5@xxxxxxxxxxx; muhammed.ali@xxxxxxxxxxx;
> thiagu.r@xxxxxxxxxxx; Selvarasu Ganesan <selvarasu.g@xxxxxxxxxxx>
> Subject: [PATCH] phy: exynos5-usbdrd: Use dynamic phy_cfg size to prevent
> OOB access
> 
> The probe loop currently iterates using EXYNOS5_DRDPHYS_NUM (2),
> creating both UTMI and PIPE3 PHY instances regardless of the SoC capability.
> Several SoCs (Exynos2200, Exynos7870, Exynos850, Exynos990, and
> ExynosAutoV920) provide phy_cfg arrays containing only a single element.
> 
> On these SoCs, when the loop reaches index 1, the driver reads past the end
> of the rodata array, populating the second PHY instance with garbage data.
> Since the configuration structure contains critical function pointers (phy_isol,
> phy_init, set_refclk), any subsequent access to this PHY instance via
> exynos5_usbdrd_phy_xlate could result in a kernel oops.
> 
> Fix this by adding 'n_phy_cfg' to struct exynos5_usbdrd_phy_drvdata to
> store the actual size of the phy_cfg array for each SoC. Update the probe
> loop and the xlate function to bound their access against this value instead of
> the hardcoded EXYNOS5_DRDPHYS_NUM.
> 
> Assisted-by: Claude:claude-sonnet-5
> Signed-off-by: Selvarasu Ganesan <selvarasu.g@xxxxxxxxxxx>
> ---
Reviewed-by: Alim Akhtar <alim.akhtar@xxxxxxxxxxx>