Re: [PATCH] EDAC/xilinx: Fix stack off-by-one in debugfs UE injection handlers

From: Datta, Shubhrajyoti

Date: Thu Apr 30 2026 - 07:27:16 EST



On 4/25/2026 12:19 AM, Shengzhuo Wei wrote:
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Two EDAC debugfs write handlers copy up to sizeof(buf) bytes into a
fixed-size stack buffer and then unconditionally NUL-terminate it via
buf[len] = '\0'. When userspace writes >= sizeof(buf) bytes, len
becomes sizeof(buf) and the NUL write lands 1 byte past the end of the
stack buffer.

Fix by clamping the copy length to sizeof(buf) - 1 so that the NUL
terminator is always in-bounds.

Fixes: 3bd2706c910f ("EDAC/zynqmp: Add EDAC support for Xilinx ZynqMP OCM")
Fixes: 83bf24051a60 ("EDAC/versal: Make the bit position of injected errors configurable")
Signed-off-by: Shengzhuo Wei <me@xxxxxxxx>
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Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxx>