From 33a154a96e71a34a1bcca9f40da343dbbf7b38b4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 1 Oct 2026 14:52:55 +0000 Subject: selftests/bpf: Test packet range of pointers sharing an id Add tests where two packet pointers share an id and tightening one pointer's umax from its var_off would put it less than their constant distance from the other's umax: with an index & 0x38 capped at 50, the base pointer keeps umax 50, so the pointer 8 bytes further on must keep umax 58, even though its known bits allow at most 56. These refused a valid program or accepted an out-of-bounds access before the fix: - check the advanced copy, load through the base: valid, was refused; - check the base, load the byte at base + 1 through a copy advanced by 8: was accepted; - check base + 4, load 4 bytes at base + 2 through base + 8: reads two bytes past the checked range, was accepted; - the same as the second with data_meta pointers checked against data: was accepted. These pass with and without the fix and cover nearby paths: - subtract an unknown scalar from a checked pointer and load below it (the range is kept across a new id); - reach a load through two paths whose checks cover 8 and 7 bytes after the loaded pointer; the second path must not be pruned by the first; - spill a copy of a pointer, check the pointer, fill the copy and load one byte past the checked range: the load is refused, and the copy has the range of the check. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- drivers/firmware/efi/ovmf-debug-log.c | 111 ++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 drivers/firmware/efi/ovmf-debug-log.c (limited to 'drivers/firmware/efi/ovmf-debug-log.c') diff --git a/drivers/firmware/efi/ovmf-debug-log.c b/drivers/firmware/efi/ovmf-debug-log.c new file mode 100644 index 000000000..5b2471ffa --- /dev/null +++ b/drivers/firmware/efi/ovmf-debug-log.c @@ -0,0 +1,111 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include +#include +#include + +#define OVMF_DEBUG_LOG_MAGIC1 0x3167646d666d766f // "ovmfmdg1" +#define OVMF_DEBUG_LOG_MAGIC2 0x3267646d666d766f // "ovmfmdg2" + +struct ovmf_debug_log_header { + u64 magic1; + u64 magic2; + u64 hdr_size; + u64 log_size; + u64 lock; // edk2 spinlock + u64 head_off; + u64 tail_off; + u64 truncated; + u8 fw_version[128]; +}; + +static struct ovmf_debug_log_header *hdr; +static u8 *logbuf; +static u64 logbufsize; + +static ssize_t ovmf_log_read(struct file *filp, struct kobject *kobj, + const struct bin_attribute *attr, char *buf, + loff_t offset, size_t count) +{ + u64 start, end; + + start = hdr->head_off + offset; + if (hdr->head_off > hdr->tail_off && start >= hdr->log_size) + start -= hdr->log_size; + + end = start + count; + if (start > hdr->tail_off) { + if (end > hdr->log_size) + end = hdr->log_size; + } else { + if (end > hdr->tail_off) + end = hdr->tail_off; + } + + if (start > logbufsize || end > logbufsize) + return 0; + if (start >= end) + return 0; + + memcpy(buf, logbuf + start, end - start); + return end - start; +} + +static struct bin_attribute ovmf_log_bin_attr = { + .attr = { + .name = "ovmf_debug_log", + .mode = 0444, + }, + .read = ovmf_log_read, +}; + +int __init ovmf_log_probe(unsigned long ovmf_debug_log_table) +{ + int ret = -EINVAL; + u64 size; + + /* map + verify header */ + hdr = memremap(ovmf_debug_log_table, sizeof(*hdr), MEMREMAP_WB); + if (!hdr) { + pr_err("OVMF debug log: header map failed\n"); + return -EINVAL; + } + + if (hdr->magic1 != OVMF_DEBUG_LOG_MAGIC1 || + hdr->magic2 != OVMF_DEBUG_LOG_MAGIC2) { + printk(KERN_ERR "OVMF debug log: magic mismatch\n"); + goto err_unmap; + } + + size = hdr->hdr_size + hdr->log_size; + pr_info("OVMF debug log: firmware version: \"%s\"\n", hdr->fw_version); + pr_info("OVMF debug log: buffer size: %lluk\n", size / 1024); + + /* map complete log buffer */ + memunmap(hdr); + hdr = memremap(ovmf_debug_log_table, size, MEMREMAP_WB); + if (!hdr) { + pr_err("OVMF debug log: buffer map failed\n"); + return -EINVAL; + } + logbuf = (void *)hdr + hdr->hdr_size; + logbufsize = hdr->log_size; + + ovmf_log_bin_attr.size = size; + ret = sysfs_create_bin_file(efi_kobj, &ovmf_log_bin_attr); + if (ret != 0) { + pr_err("OVMF debug log: sysfs register failed\n"); + goto err_unmap; + } + + return 0; + +err_unmap: + memunmap(hdr); + return ret; +} -- cgit v1.3.1