From: Nicholas Piggin Date: Tue, 6 Aug 2024 15:13:21 +0000 (+1000) Subject: ppc/pnv: ADU fix possible buffer overrun with invalid size X-Git-Tag: pull-vmclock-20250108~88^2~57 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ddd2a060a0da41000ddca31e329ab1d54e37fedb;p=users%2Fdwmw2%2Fqemu.git ppc/pnv: ADU fix possible buffer overrun with invalid size The ADU LPC transfer-size field is 7 bits, but the supported sizes for LPC access via ADU appear to be 1, 2, 4, 8. The data buffer could overrun if firmware set an invalid size field, so add checks to reject them with a message. Cc: qemu-stable@nongnu.org Reported-by: Cédric Le Goater Resolves: Coverity CID 1558830 Fixes: 24bd283bccb33 ("ppc/pnv: Implement ADU access to LPC space") Reviewed-by: Cédric Le Goater Signed-off-by: Nicholas Piggin --- diff --git a/hw/ppc/pnv_adu.c b/hw/ppc/pnv_adu.c index 81b7d6e526..f636dedf79 100644 --- a/hw/ppc/pnv_adu.c +++ b/hw/ppc/pnv_adu.c @@ -116,6 +116,12 @@ static void pnv_adu_xscom_write(void *opaque, hwaddr addr, uint64_t val, uint32_t lpc_size = lpc_cmd_size(adu); uint64_t data = 0; + if (!is_power_of_2(lpc_size) || lpc_size > sizeof(data)) { + qemu_log_mask(LOG_GUEST_ERROR, "ADU: Unsupported LPC access " + "size:%" PRId32 "\n", lpc_size); + break; + } + pnv_lpc_opb_read(adu->lpc, lpc_addr, (void *)&data, lpc_size); /* @@ -135,6 +141,12 @@ static void pnv_adu_xscom_write(void *opaque, hwaddr addr, uint64_t val, uint32_t lpc_size = lpc_cmd_size(adu); uint64_t data; + if (!is_power_of_2(lpc_size) || lpc_size > sizeof(data)) { + qemu_log_mask(LOG_GUEST_ERROR, "ADU: Unsupported LPC access " + "size:%" PRId32 "\n", lpc_size); + break; + } + data = cpu_to_be64(val) >> ((lpc_addr & 7) * 8); /* See above */ pnv_lpc_opb_write(adu->lpc, lpc_addr, (void *)&data, lpc_size); }