@@ -59,6 +59,7 @@ obj-y += wait.o
obj-$(CONFIG_XENOPROF) += xenoprof.o
obj-y += xmalloc_tlsf.o
obj-$(CONFIG_XSPLICE) += xsplice.o
+obj-$(CONFIG_XSPLICE) += xsplice_elf.o
obj-bin-$(CONFIG_X86) += $(foreach n,decompress bunzip2 unxz unlzma unlzo unlz4 earlycpio,$(n).init.o)
new file mode 100644
@@ -0,0 +1,375 @@
+/*
+ * Copyright (C) 2016 Citrix Systems R&D Ltd.
+ */
+
+#include <xen/errno.h>
+#include <xen/lib.h>
+#include <xen/xsplice_elf.h>
+#include <xen/xsplice.h>
+
+const struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
+ const char *name)
+{
+ unsigned int i;
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( !strcmp(name, elf->sec[i].name) )
+ return &elf->sec[i];
+ }
+
+ return NULL;
+}
+
+static int elf_verify_strtab(const struct xsplice_elf_sec *sec)
+{
+ const Elf_Shdr *s;
+ const char *contents;
+
+ s = sec->sec;
+
+ if ( s->sh_type != SHT_STRTAB )
+ return -EINVAL;
+
+ if ( !s->sh_size )
+ return -EINVAL;
+
+ contents = sec->data;
+
+ if ( contents[0] || contents[s->sh_size - 1] )
+ return -EINVAL;
+
+ return 0;
+}
+
+static int elf_resolve_sections(struct xsplice_elf *elf, const void *data)
+{
+ struct xsplice_elf_sec *sec;
+ unsigned int i;
+ Elf_Off delta;
+ int rc;
+
+ /* xsplice_elf_load sanity checked e_shnum. */
+ sec = xmalloc_array(struct xsplice_elf_sec, elf->hdr->e_shnum);
+ if ( !sec )
+ {
+ dprintk(XENLOG_ERR, XSPLICE"%s: Could not allocate memory for section table!\n",
+ elf->name);
+ return -ENOMEM;
+ }
+
+ elf->sec = sec;
+
+ /* e_shoff and e_shnum overflow checks are done in xsplice_header_check. */
+ delta = elf->hdr->e_shoff + elf->hdr->e_shnum * elf->hdr->e_shentsize;
+ if ( delta > elf->len )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section table is past end of payload!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
+
+ sec[i].sec = data + delta;
+
+ delta = sec[i].sec->sh_offset;
+ /*
+ * N.B. elf_resolve_section_names, elf_get_sym skip this check as
+ * we do it here.
+ */
+ if ( delta < sizeof(Elf_Ehdr) ||
+ (sec[i].sec->sh_type != SHT_NOBITS && /* Skip SHT_NOBITS */
+ (delta > elf->len || (delta + sec[i].sec->sh_size > elf->len))) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section [%u] data %s of payload!\n",
+ elf->name, i,
+ delta < sizeof(Elf_Ehdr) ? "at ELF header" : "is past end");
+ return -EINVAL;
+ }
+
+ sec[i].data = data + delta;
+ /* Name is populated in elf_resolve_section_names. */
+ sec[i].name = NULL;
+
+ if ( sec[i].sec->sh_type == SHT_SYMTAB )
+ {
+ if ( elf->symtab )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Unsupported multiple symbol tables!\n",
+ elf->name);
+ return -EOPNOTSUPP;
+ }
+
+ elf->symtab = &sec[i];
+
+ /*
+ * elf->symtab->sec->sh_link would point to the right section
+ * but we hadn't finished parsing all the sections.
+ */
+ if ( elf->symtab->sec->sh_link >= elf->hdr->e_shnum )
+ {
+ dprintk(XENLOG_ERR, XSPLICE
+ "%s: Symbol table idx (%u) to strtab past end (%u)\n",
+ elf->name, elf->symtab->sec->sh_link,
+ elf->hdr->e_shnum);
+ return -EINVAL;
+ }
+ }
+ }
+
+ if ( !elf->symtab )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: No symbol table found!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ if ( !elf->symtab->sec->sh_size ||
+ elf->symtab->sec->sh_entsize < sizeof(Elf_Sym) ||
+ elf->symtab->sec->sh_size % elf->symtab->sec->sh_entsize )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Symbol table header is corrupted!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ /*
+ * There can be multiple SHT_STRTAB (.shstrtab, .strtab) so pick the one
+ * associated with the symbol table.
+ */
+ elf->strtab = &sec[elf->symtab->sec->sh_link];
+
+ rc = elf_verify_strtab(elf->strtab);
+ if ( rc )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: String table section is corrupted\n",
+ elf->name);
+ }
+
+ return rc;
+}
+
+static int elf_resolve_section_names(struct xsplice_elf *elf, const void *data)
+{
+ const char *shstrtab;
+ unsigned int i;
+ Elf_Off offset, delta;
+ struct xsplice_elf_sec *sec;
+ int rc;
+
+ /*
+ * The elf->sec[0 -> e_shnum] structures have been verified by
+ * elf_resolve_sections. Find file offset for section string table
+ * (normally called .shstrtab)
+ */
+ sec = &elf->sec[elf->hdr->e_shstrndx];
+
+ rc = elf_verify_strtab(sec);
+ if ( rc )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section string table is corrupted\n",
+ elf->name);
+ return rc;
+ }
+
+ /* Verified in elf_resolve_sections but just in case. */
+ offset = sec->sec->sh_offset;
+ ASSERT(offset < elf->len && (offset + sec->sec->sh_size <= elf->len));
+
+ shstrtab = data + offset;
+
+ for ( i = 1; i < elf->hdr->e_shnum; i++ )
+ {
+ delta = elf->sec[i].sec->sh_name;
+
+ /* Boundary check on offset of name within the .shstrtab. */
+ if ( delta >= sec->sec->sh_size )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: shstrtab [%u] data is past end of payload!\n",
+ elf->name, i);
+ return -EINVAL;
+ }
+
+ elf->sec[i].name = shstrtab + delta;
+ }
+
+ return 0;
+}
+
+static int elf_get_sym(struct xsplice_elf *elf, const void *data)
+{
+ const struct xsplice_elf_sec *symtab_sec, *strtab_sec;
+ struct xsplice_elf_sym *sym;
+ unsigned int i, delta, offset, nsym;
+
+ symtab_sec = elf->symtab;
+ strtab_sec = elf->strtab;
+
+ /* Pointers arithmetic to get file offset. */
+ offset = strtab_sec->data - data;
+
+ /* Checked already in elf_resolve_sections, but just in case. */
+ ASSERT(offset == strtab_sec->sec->sh_offset);
+ ASSERT(offset < elf->len && (offset + strtab_sec->sec->sh_size <= elf->len));
+
+ /* symtab_sec->data was computed in elf_resolve_sections. */
+ ASSERT((symtab_sec->sec->sh_offset + data) == symtab_sec->data);
+
+ /* No need to check values as elf_resolve_sections did it. */
+ nsym = symtab_sec->sec->sh_size / symtab_sec->sec->sh_entsize;
+
+ sym = xmalloc_array(struct xsplice_elf_sym, nsym);
+ if ( !sym )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Could not allocate memory for symbols\n",
+ elf->name);
+ return -ENOMEM;
+ }
+
+ /* So we don't leak memory. */
+ elf->sym = sym;
+
+ for ( i = 1; i < nsym; i++ )
+ {
+ const Elf_Sym *s = symtab_sec->data + symtab_sec->sec->sh_entsize * i;
+
+ delta = s->st_name;
+ /* Boundary check within the .strtab. */
+ if ( delta >= strtab_sec->sec->sh_size )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Symbol [%u] name is not within .strtab!\n",
+ elf->name, i);
+ return -EINVAL;
+ }
+
+ sym[i].sym = s;
+ sym[i].name = strtab_sec->data + delta;
+ }
+ elf->nsym = nsym;
+
+ return 0;
+}
+
+static int xsplice_header_check(const struct xsplice_elf *elf)
+{
+ const Elf_Ehdr *hdr = elf->hdr;
+
+ if ( sizeof(*elf->hdr) > elf->len )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header is bigger than payload!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ if ( !IS_ELF(*hdr) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Not an ELF payload!\n", elf->name);
+ return -EINVAL;
+ }
+
+ /* EI_CLASS, and e_flags are platform specific. */
+ if ( hdr->e_version != EV_CURRENT ||
+ hdr->e_ident[EI_VERSION] != EV_CURRENT ||
+ hdr->e_ident[EI_DATA] != ELFDATA2LSB ||
+ hdr->e_ident[EI_OSABI] != ELFOSABI_SYSV ||
+ hdr->e_type != ET_REL ||
+ hdr->e_phnum != 0 )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Invalid ELF payload!\n", elf->name);
+ return -EOPNOTSUPP;
+ }
+
+ if ( elf->hdr->e_shstrndx == SHN_UNDEF )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx is undefined!?\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ /* Check that section name index is within the sections. */
+ if ( elf->hdr->e_shstrndx >= elf->hdr->e_shnum )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section name idx (%u) is past end of sections (%u)!\n",
+ elf->name, elf->hdr->e_shstrndx, elf->hdr->e_shnum);
+ return -EINVAL;
+ }
+
+ if ( elf->hdr->e_shnum >= SHN_LORESERVE )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Too many (%u) sections!\n",
+ elf->name, elf->hdr->e_shnum);
+ return -EOPNOTSUPP;
+ }
+
+ if ( elf->hdr->e_shoff >= elf->len || elf->hdr->e_shoff >= ULONG_MAX )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Bogus e_shoff!\n", elf->name);
+ return -EINVAL;
+ }
+
+ if ( elf->hdr->e_shentsize < sizeof(Elf_Shdr) )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header size is %u! Expected %zu!?\n",
+ elf->name, elf->hdr->e_shentsize, sizeof(Elf_Shdr));
+ return -EINVAL;
+ }
+
+ if ( ((elf->len - elf->hdr->e_shoff) / elf->hdr->e_shentsize) <
+ elf->hdr->e_shnum )
+ {
+ dprintk(XENLOG_ERR, XSPLICE "%s: Section header size is corrupted!\n",
+ elf->name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int xsplice_elf_load(struct xsplice_elf *elf, const void *data)
+{
+ int rc;
+
+ elf->hdr = data;
+
+ rc = xsplice_header_check(elf);
+ if ( rc )
+ return rc;
+
+ rc = elf_resolve_sections(elf, data);
+ if ( rc )
+ return rc;
+
+ rc = elf_resolve_section_names(elf, data);
+ if ( rc )
+ return rc;
+
+ rc = elf_get_sym(elf, data);
+ if ( rc )
+ return rc;
+
+ return 0;
+}
+
+void xsplice_elf_free(struct xsplice_elf *elf)
+{
+ xfree(elf->sec);
+ elf->sec = NULL;
+ xfree(elf->sym);
+ elf->sym = NULL;
+ elf->nsym = 0;
+ elf->name = NULL;
+ elf->len = 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
@@ -10,6 +10,9 @@ struct xen_sysctl_xsplice_op;
#ifdef CONFIG_XSPLICE
+/* Convenience define for printk. */
+#define XSPLICE "xsplice: "
+
int xsplice_op(struct xen_sysctl_xsplice_op *);
#else
new file mode 100644
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2016 Citrix Systems R&D Ltd.
+ */
+
+#ifndef __XEN_XSPLICE_ELF_H__
+#define __XEN_XSPLICE_ELF_H__
+
+#include <xen/types.h>
+#include <xen/elfstructs.h>
+
+/* The following describes an Elf file as consumed by xSplice. */
+struct xsplice_elf_sec {
+ const Elf_Shdr *sec; /* Hooked up in elf_resolve_sections.*/
+ const char *name; /* Human readable name hooked in
+ elf_resolve_section_names. */
+ const void *data; /* Pointer to the section (done by
+ elf_resolve_sections). */
+};
+
+struct xsplice_elf_sym {
+ const Elf_Sym *sym;
+ const char *name;
+};
+
+struct xsplice_elf {
+ const char *name; /* Pointer to payload->name. */
+ size_t len; /* Length of the ELF file. */
+ const Elf_Ehdr *hdr; /* ELF file. */
+ struct xsplice_elf_sec *sec; /* Array of sections, allocated by us. */
+ struct xsplice_elf_sym *sym; /* Array of symbols , allocated by us. */
+ unsigned int nsym;
+ const struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to sec[x]. */
+ const struct xsplice_elf_sec *strtab;/* Pointer to .strtab section - aka to sec[y]. */
+};
+
+const struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
+ const char *name);
+int xsplice_elf_load(struct xsplice_elf *elf, const void *data);
+void xsplice_elf_free(struct xsplice_elf *elf);
+
+#endif /* __XEN_XSPLICE_ELF_H__ */
+
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
+ * End:
+ */