From: Muhammad Bilal Date: Sun, 24 May 2026 13:03:19 +0000 (+0000) Subject: accel/ethosu: reject DMA commands with uninitialized length X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=d9d021218162b6c4fe0bdf42b2b340f1aae23a12;p=thirdparty%2Fkernel%2Flinux.git accel/ethosu: reject DMA commands with uninitialized length cmd_state_init() initializes the command state with memset(0xff), leaving dma->len at U64_MAX to signal missing setup. The only setter is NPU_SET_DMA0_LEN; if userspace omits this command and issues NPU_OP_DMA_START, dma->len remains U64_MAX. In dma_length(), a positive stride added to U64_MAX wraps to a small value. With size0 == 1, check_mul_overflow() does not trigger and dma_length() returns 0 instead of U64_MAX. The caller's U64_MAX check then passes, region_size[] stays 0, and the bounds check in ethosu_job.c is bypassed, allowing hardware to execute DMA with stale physical addresses. Fix by checking for U64_MAX at the start of dma_length() before any arithmetic, consistent with the sentinel value used throughout the driver to detect uninitialized fields. Fixes: 5a5e9c0228e6 ("accel: Add Arm Ethos-U NPU driver") Cc: stable@vger.kernel.org Signed-off-by: Muhammad Bilal Link: https://patch.msgid.link/20260524130319.12747-1-meatuni001@gmail.com Signed-off-by: Rob Herring (Arm) --- diff --git a/drivers/accel/ethosu/ethosu_gem.c b/drivers/accel/ethosu/ethosu_gem.c index 27c5fdbe9a5d..2cb7964ddfa5 100644 --- a/drivers/accel/ethosu/ethosu_gem.c +++ b/drivers/accel/ethosu/ethosu_gem.c @@ -164,6 +164,9 @@ static u64 dma_length(struct ethosu_validated_cmdstream_info *info, s8 mode = dma_st->mode; u64 len = dma->len; + if (len == U64_MAX) + return U64_MAX; + if (mode >= 1) { if (dma->stride[0] < 0 && (u64)(-dma->stride[0]) > len) return U64_MAX;