Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 191 insertions, 0 deletions

diff --git a/lib/buildid.c b/lib/buildid.c
new file mode 100644
index 000000000..dfc62625c
--- /dev/null
+++ b/lib/buildid.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/buildid.h>
+#include <linux/cache.h>
+#include <linux/elf.h>
+#include <linux/kernel.h>
+#include <linux/pagemap.h>
+
+#define BUILD_ID 3
+
+/*
+ * Parse build id from the note segment. This logic can be shared between
+ * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
+ * identical.
+ */
+static int parse_build_id_buf(unsigned char *build_id,
+			      __u32 *size,
+			      const void *note_start,
+			      Elf32_Word note_size)
+{
+	Elf32_Word note_offs = 0, new_offs;
+
+	while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
+		Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
+
+		if (nhdr->n_type == BUILD_ID &&
+		    nhdr->n_namesz == sizeof("GNU") &&
+		    !strcmp((char *)(nhdr + 1), "GNU") &&
+		    nhdr->n_descsz > 0 &&
+		    nhdr->n_descsz <= BUILD_ID_SIZE_MAX) {
+			memcpy(build_id,
+			       note_start + note_offs +
+			       ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
+			       nhdr->n_descsz);
+			memset(build_id + nhdr->n_descsz, 0,
+			       BUILD_ID_SIZE_MAX - nhdr->n_descsz);
+			if (size)
+				*size = nhdr->n_descsz;
+			return 0;
+		}
+		new_offs = note_offs + sizeof(Elf32_Nhdr) +
+			ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
+		if (new_offs <= note_offs)  /* overflow */
+			break;
+		note_offs = new_offs;
+	}
+
+	return -EINVAL;
+}
+
+static inline int parse_build_id(const void *page_addr,
+				 unsigned char *build_id,
+				 __u32 *size,
+				 const void *note_start,
+				 Elf32_Word note_size)
+{
+	/* check for overflow */
+	if (note_start < page_addr || note_start + note_size < note_start)
+		return -EINVAL;
+
+	/* only supports note that fits in the first page */
+	if (note_start + note_size > page_addr + PAGE_SIZE)
+		return -EINVAL;
+
+	return parse_build_id_buf(build_id, size, note_start, note_size);
+}
+
+/* Parse build ID from 32-bit ELF */
+static int get_build_id_32(const void *page_addr, unsigned char *build_id,
+			   __u32 *size)
+{
+	Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
+	Elf32_Phdr *phdr;
+	int i;
+
+	/* only supports phdr that fits in one page */
+	if (ehdr->e_phnum >
+	    (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
+		return -EINVAL;
+
+	phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
+
+	for (i = 0; i < ehdr->e_phnum; ++i) {
+		if (phdr[i].p_type == PT_NOTE &&
+		    !parse_build_id(page_addr, build_id, size,
+				    page_addr + phdr[i].p_offset,
+				    phdr[i].p_filesz))
+			return 0;
+	}
+	return -EINVAL;
+}
+
+/* Parse build ID from 64-bit ELF */
+static int get_build_id_64(const void *page_addr, unsigned char *build_id,
+			   __u32 *size)
+{
+	Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
+	Elf64_Phdr *phdr;
+	int i;
+
+	/* only supports phdr that fits in one page */
+	if (ehdr->e_phnum >
+	    (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
+		return -EINVAL;
+
+	phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
+
+	for (i = 0; i < ehdr->e_phnum; ++i) {
+		if (phdr[i].p_type == PT_NOTE &&
+		    !parse_build_id(page_addr, build_id, size,
+				    page_addr + phdr[i].p_offset,
+				    phdr[i].p_filesz))
+			return 0;
+	}
+	return -EINVAL;
+}
+
+/*
+ * Parse build ID of ELF file mapped to vma
+ * @vma:      vma object
+ * @build_id: buffer to store build id, at least BUILD_ID_SIZE long
+ * @size:     returns actual build id size in case of success
+ *
+ * Return: 0 on success, -EINVAL otherwise
+ */
+int build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
+		   __u32 *size)
+{
+	Elf32_Ehdr *ehdr;
+	struct page *page;
+	void *page_addr;
+	int ret;
+
+	/* only works for page backed storage  */
+	if (!vma->vm_file)
+		return -EINVAL;
+
+	page = find_get_page(vma->vm_file->f_mapping, 0);
+	if (!page)
+		return -EFAULT;	/* page not mapped */
+
+	ret = -EINVAL;
+	page_addr = kmap_atomic(page);
+	ehdr = (Elf32_Ehdr *)page_addr;
+
+	/* compare magic x7f "ELF" */
+	if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
+		goto out;
+
+	/* only support executable file and shared object file */
+	if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
+		goto out;
+
+	if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
+		ret = get_build_id_32(page_addr, build_id, size);
+	else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
+		ret = get_build_id_64(page_addr, build_id, size);
+out:
+	kunmap_atomic(page_addr);
+	put_page(page);
+	return ret;
+}
+
+/**
+ * build_id_parse_buf - Get build ID from a buffer
+ * @buf:      Elf note section(s) to parse
+ * @buf_size: Size of @buf in bytes
+ * @build_id: Build ID parsed from @buf, at least BUILD_ID_SIZE_MAX long
+ *
+ * Return: 0 on success, -EINVAL otherwise
+ */
+int build_id_parse_buf(const void *buf, unsigned char *build_id, u32 buf_size)
+{
+	return parse_build_id_buf(build_id, NULL, buf, buf_size);
+}
+
+#if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID) || IS_ENABLED(CONFIG_CRASH_CORE)
+unsigned char vmlinux_build_id[BUILD_ID_SIZE_MAX] __ro_after_init;
+
+/**
+ * init_vmlinux_build_id - Compute and stash the running kernel's build ID
+ */
+void __init init_vmlinux_build_id(void)
+{
+	extern const void __start_notes __weak;
+	extern const void __stop_notes __weak;
+	unsigned int size = &__stop_notes - &__start_notes;
+
+	build_id_parse_buf(&__start_notes, vmlinux_build_id, size);
+}
+#endif