From: Kees Cook keescook@chromium.org

[ Upstream commit b3bcedc0402fcdc5c8624c433562d9d1882749d8 ]

Walking the dram->cs array was seen as accesses beyond the first array item by the compiler. Instead, use the array index directly. This allows for run-time bounds checking under CONFIG_UBSAN_BOUNDS as well. Seen with GCC 13 with -fstrict-flex-arrays:

../sound/soc/kirkwood/kirkwood-dma.c: In function 'kirkwood_dma_conf_mbus_windows.constprop': ../sound/soc/kirkwood/kirkwood-dma.c:90:24: warning: array subscript 0 is outside array bounds of 'const struct mbus_dram_window[0]' [-Warray-bounds=] 90 | if ((cs->base & 0xffff0000) < (dma & 0xffff0000)) { | ~~^~~~~~

Cc: Liam Girdwood lgirdwood@gmail.com Cc: Mark Brown broonie@kernel.org Cc: Jaroslav Kysela perex@perex.cz Cc: Takashi Iwai tiwai@suse.com Cc: alsa-devel@alsa-project.org Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20230127224128.never.410-kees@kernel.org Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- sound/soc/kirkwood/kirkwood-dma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/kirkwood/kirkwood-dma.c b/sound/soc/kirkwood/kirkwood-dma.c index 700a18561a940..640cebd2983e2 100644 --- a/sound/soc/kirkwood/kirkwood-dma.c +++ b/sound/soc/kirkwood/kirkwood-dma.c @@ -86,7 +86,7 @@ kirkwood_dma_conf_mbus_windows(void __iomem *base, int win,

/* try to find matching cs for current dma address */ for (i = 0; i < dram->num_cs; i++) { - const struct mbus_dram_window *cs = dram->cs + i; + const struct mbus_dram_window *cs = &dram->cs[i]; if ((cs->base & 0xffff0000) < (dma & 0xffff0000)) { writel(cs->base & 0xffff0000, base + KIRKWOOD_AUDIO_WIN_BASE_REG(win));