From 5d64275517dd641a115ff3a1e12d16fea5a4f180 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 23 Jul 2024 14:10:26 +0100 Subject: [PATCH] hw/misc/bcm2835_property: Fix handling of FRAMEBUFFER_SET_PALETTE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The documentation of the "Set palette" mailbox property at https://github.com/raspberrypi/firmware/wiki/Mailbox-property-interface#set-palette says it has the form: Length: 24..1032 Value: u32: offset: first palette index to set (0-255) u32: length: number of palette entries to set (1-256) u32...: RGBA palette values (offset to offset+length-1) We get this wrong in a couple of ways: * we aren't checking the offset and length are in range, so the guest can make us spin for a long time by providing a large length * the bounds check on our loop is wrong: we should iterate through 'length' palette entries, not 'length - offset' entries Fix the loop to implement the bounds checks and get the loop condition right. In the process, make the variables local to this switch case, rather than function-global, so it's clearer what type they are when reading the code. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé Message-id: 20240723131029.1159908-2-peter.maydell@linaro.org (cherry picked from commit 0892fffc2abaadfb5d8b79bb0250ae1794862560) Signed-off-by: Michael Tokarev (Mjt: context fix due to lack of v9.0.0-1812-g5d5f1b60916a "hw/misc: Implement mailbox properties for customer OTP and device specific private keys" v8.0.0-1924-g251918266666 "hw/misc/bcm2835_property: Use 'raspberrypi-fw-defs.h' definitions" also remove now-unused local `n' variable which gets removed in the next change in this file, v9.0.0-2720-g32f1c201eedf "hw/misc/bcm2835_property: Avoid overflow in OTP access properties") --- hw/misc/bcm2835_property.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/hw/misc/bcm2835_property.c b/hw/misc/bcm2835_property.c index de056ea2df..c7834d3fc7 100644 --- a/hw/misc/bcm2835_property.c +++ b/hw/misc/bcm2835_property.c @@ -26,8 +26,6 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value) uint32_t tot_len; size_t resplen; uint32_t tmp; - int n; - uint32_t offset, length, color; /* * Copy the current state of the framebuffer config; we will update @@ -258,18 +256,25 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value) resplen = 16; break; case 0x0004800b: /* Set palette */ - offset = ldl_le_phys(&s->dma_as, value + 12); - length = ldl_le_phys(&s->dma_as, value + 16); - n = 0; - while (n < length - offset) { - color = ldl_le_phys(&s->dma_as, value + 20 + (n << 2)); - stl_le_phys(&s->dma_as, - s->fbdev->vcram_base + ((offset + n) << 2), color); - n++; + { + uint32_t offset = ldl_le_phys(&s->dma_as, value + 12); + uint32_t length = ldl_le_phys(&s->dma_as, value + 16); + int resp; + + if (offset > 255 || length < 1 || length > 256) { + resp = 1; /* invalid request */ + } else { + for (uint32_t e = 0; e < length; e++) { + uint32_t color = ldl_le_phys(&s->dma_as, value + 20 + (e << 2)); + stl_le_phys(&s->dma_as, + s->fbdev->vcram_base + ((offset + e) << 2), color); + } + resp = 0; } - stl_le_phys(&s->dma_as, value + 12, 0); + stl_le_phys(&s->dma_as, value + 12, resp); resplen = 4; break; + } case 0x00040013: /* Get number of displays */ stl_le_phys(&s->dma_as, value + 12, 1); resplen = 4;