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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 13/23] XENVER_build_id: Provide ld-embedded build-ids (v10)
The mechanism to get this is via the XENVER hypercall and
we add a new sub-command to retrieve the binary build-id
called XENVER_build_id. The sub-hypercall parameter
allows an arbitrary size (the buffer and len is provided
to the hypervisor). A NULL parameter will probe the hypervisor
for the length of the build-id.
One can also retrieve the value of the build-id by doing
'readelf -n xen-syms'.
For EFI builds we re-use the same build-id that the xen-syms
was built with.
The version of ld that first implemented --build-id is v2.18.
Hence we check for that or later version - if older version
found we do not build the hypervisor with the build-id
(and the return code is -ENODATA for that case).
For x86 we have two binaries - the xen-syms and the xen - an
smaller version with lots of sections removed. To make it possible
for readelf -n xen we also modify mkelf32 and xen.lds.S to include
the PT_NOTE ELF section.
The EFI binary is more complicated. Having any non-recognizable
sections (.note, .data.note, etc) causes the boot to hang.
Moving the .note in the .data section makes it work. It is also
worth noting that the PE/COFF does not have any "comment"
sections to the author.
Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Martin Pohlack <mpohlack@xxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
v1: Rebase it on Martin's initial patch
v2: Move it to XENVER hypercall
v3: Fix EFI building (Ross's fix)
v4: Don't use the third argument for length.
v5: Use new structure for XENVER_build_id with variable buf.
v6: Include Ross's fix.
v7: Include detection of bin-utils for build-id support, add
probing for size, and return -EPERM for XSM denied calls.
v8: Build xen_build_id under ARM, required adding ELFSIZE in proper file.
v9: Rebase on top XSM version class.
v10: Include the build-id .note in the xen ELF binary.
s/build_id/build_id_linker/
For EFI build, moved the --build-id values in .data section
---
Config.mk | 11 +++
tools/flask/policy/policy/modules/xen/xen.te | 4 +-
tools/libxc/xc_private.c | 7 ++
tools/libxc/xc_private.h | 10 ++
xen/arch/arm/Makefile | 2 +-
xen/arch/arm/xen.lds.S | 13 +++
xen/arch/x86/Makefile | 31 +++++-
xen/arch/x86/boot/mkelf32.c | 137 +++++++++++++++++++++++----
xen/arch/x86/xen.lds.S | 23 +++++
xen/common/kernel.c | 36 +++++++
xen/common/version.c | 48 ++++++++++
xen/include/public/version.h | 16 +++-
xen/include/xen/version.h | 1 +
xen/xsm/flask/hooks.c | 3 +
xen/xsm/flask/policy/access_vectors | 2 +
15 files changed, 319 insertions(+), 25 deletions(-)
diff --git a/Config.mk b/Config.mk
index 429e460..61186e2 100644
--- a/Config.mk
+++ b/Config.mk
@@ -126,6 +126,17 @@ endef
check-$(gcc) = $(call cc-ver-check,CC,0x040100,"Xen requires at least gcc-4.1")
$(eval $(check-y))
+ld-ver-build-id = $(shell $(1) --build-id 2>&1 | \
+ grep -q unrecognized && echo n || echo
y)
+
+# binutils 2.18 implement build-id.
+ifeq ($(call ld-ver-build-id,$(LD)),n)
+build_id_linker :=
+else
+CFLAGS += -DBUILD_ID
+build_id_linker := --build-id=sha1
+endif
+
# as-insn: Check whether assembler supports an instruction.
# Usage: cflags-y += $(call as-insn "insn",option-yes,option-no)
as-insn = $(if $(shell echo 'void _(void) { asm volatile ( $(2) ); }' \
diff --git a/tools/flask/policy/policy/modules/xen/xen.te
b/tools/flask/policy/policy/modules/xen/xen.te
index 9ad648a..2988954 100644
--- a/tools/flask/policy/policy/modules/xen/xen.te
+++ b/tools/flask/policy/policy/modules/xen/xen.te
@@ -79,7 +79,7 @@ allow dom0_t xen_t:xen2 {
# Note that dom0 is part of domain_type so this has duplicates.
allow dom0_t xen_t:version {
version extraversion compile_info capabilities changeset
- platform_parameters get_features pagesize guest_handle commandline
+ platform_parameters get_features pagesize guest_handle commandline build_id
};
allow dom0_t xen_t:mmu memorymap;
@@ -146,7 +146,7 @@ if (guest_writeconsole) {
# pmu_ctrl is for)
allow domain_type xen_t:xen2 pmu_use;
-# For normal guests all except XENVER_commandline
+# For normal guests all except XENVER_commandline|build_id
allow domain_type xen_t:version {
version extraversion compile_info capabilities changeset
platform_parameters get_features pagesize guest_handle
diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index c41e433..d57c39a 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -495,6 +495,13 @@ int xc_version(xc_interface *xch, int cmd, void *arg)
case XENVER_commandline:
sz = sizeof(xen_commandline_t);
break;
+ case XENVER_build_id:
+ {
+ xen_build_id_t *build_id = (xen_build_id_t *)arg;
+ sz = sizeof(*build_id) + build_id->len;
+ HYPERCALL_BOUNCE_SET_DIR(arg, XC_HYPERCALL_BUFFER_BOUNCE_BOTH);
+ break;
+ }
default:
ERROR("xc_version: unknown command %d\n", cmd);
return -EINVAL;
diff --git a/tools/libxc/xc_private.h b/tools/libxc/xc_private.h
index aa8daf1..6b592d3 100644
--- a/tools/libxc/xc_private.h
+++ b/tools/libxc/xc_private.h
@@ -191,6 +191,16 @@ enum {
#define DECLARE_HYPERCALL_BOUNCE(_ubuf, _sz, _dir)
DECLARE_NAMED_HYPERCALL_BOUNCE(_ubuf, _ubuf, _sz, _dir)
/*
+ * Change the direction.
+ *
+ * Can only be used if the bounce_pre/bounce_post commands have
+ * not been used.
+ */
+#define HYPERCALL_BOUNCE_SET_DIR(_buf, _dir) do { if
((HYPERCALL_BUFFER(_buf))->hbuf) \
+ assert(1);
\
+
(HYPERCALL_BUFFER(_buf))->dir = _dir; \
+ } while (0)
+/*
* Set the size of data to bounce. Useful when the size is not known
* when the bounce buffer is declared.
*/
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 35ba293..8491267 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -93,7 +93,7 @@ $(TARGET)-syms: prelink.o xen.lds
$(BASEDIR)/common/symbols-dummy.o
$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
| $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).1.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
$(@D)/.$(@F).1.o -o $@
rm -f $(@D)/.$(@F).[0-9]*
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index f501a2f..5cf180f 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -22,6 +22,9 @@ OUTPUT_ARCH(FORMAT)
PHDRS
{
text PT_LOAD /* XXX should be AT ( XEN_PHYS_START ) */ ;
+#if defined(BUILD_ID)
+ note PT_NOTE ;
+#endif
}
SECTIONS
{
@@ -53,6 +56,16 @@ SECTIONS
_erodata = .; /* End of read-only data */
} :text
+#if defined(BUILD_ID)
+ .note : {
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+ *(.note)
+ *(.note.*)
+ } :text
+#endif
+
.data : { /* Data */
. = ALIGN(PAGE_SIZE);
*(.data.page_aligned)
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 8cce4ba..4a19ae9 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -71,9 +71,16 @@ efi-y := $(shell if [ ! -r $(BASEDIR)/include/xen/compile.h
-o \
-O $(BASEDIR)/include/xen/compile.h ]; then \
echo '$(TARGET).efi'; fi)
+ifdef build_id_linker
+num_phdrs = 2
+else
+num_phdrs = 1
+endif
+
$(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
./boot/mkelf32 $(TARGET)-syms $(TARGET) 0x100000 \
- `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'`
+ `$(NM) -nr $(TARGET)-syms | head -n 1 | sed -e 's/^\([^ ]*\).*/0x\1/'` \
+ $(num_phdrs)
$(MAKE) -f $(BASEDIR)/Rules.mk -C test
install:
@@ -109,20 +116,27 @@ $(BASEDIR)/common/symbols-dummy.o:
$(MAKE) -f $(BASEDIR)/Rules.mk -C $(BASEDIR)/common symbols-dummy.o
$(TARGET)-syms: prelink.o xen.lds $(BASEDIR)/common/symbols-dummy.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
$(BASEDIR)/common/symbols-dummy.o -o $(@D)/.$(@F).0
$(NM) -pa --format=sysv $(@D)/.$(@F).0 \
| $(BASEDIR)/tools/symbols --sysv --sort >$(@D)/.$(@F).0.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).0.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
$(@D)/.$(@F).0.o -o $(@D)/.$(@F).1
$(NM) -pa --format=sysv $(@D)/.$(@F).1 \
| $(BASEDIR)/tools/symbols --sysv --sort --warn-dup
>$(@D)/.$(@F).1.S
$(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1.o
- $(LD) $(LDFLAGS) -T xen.lds -N prelink.o \
+ $(LD) $(LDFLAGS) -T xen.lds -N prelink.o $(build_id_linker) \
$(@D)/.$(@F).1.o -o $@
rm -f $(@D)/.$(@F).[0-9]*
+build_id.o: $(TARGET)-syms
+ $(OBJCOPY) --only-section=.note $< .$@.0
+ # Need to clear the CODE when the build_id.o is put in the .data
+ $(OBJCOPY) --set-section-flags=.note=alloc,load,data \
+ --rename-section=.note=.note.gnu.build-id .$@.0 $@
+ rm -f .$@.0
+
EFI_LDFLAGS = $(patsubst -m%,-mi386pep,$(LDFLAGS)) --subsystem=10
EFI_LDFLAGS += --image-base=$(1) --stack=0,0 --heap=0,0 --strip-debug
EFI_LDFLAGS += --section-alignment=0x200000 --file-alignment=0x20
@@ -135,6 +149,13 @@ $(TARGET).efi: VIRT_BASE = 0x$(shell $(NM)
efi/relocs-dummy.o | sed -n 's, A VIR
$(TARGET).efi: ALT_BASE = 0x$(shell $(NM) efi/relocs-dummy.o | sed -n 's, A
ALT_START$$,,p')
# Don't use $(wildcard ...) here - at least make 3.80 expands this too early!
$(TARGET).efi: guard = $(if $(shell echo efi/dis* | grep disabled),:)
+ifdef build_id_linker
+$(TARGET).efi: build_id.o
+build_id_file := build_id.o
+else
+build_id_file :=
+endif
+
$(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o
$(BASEDIR)/common/symbols-dummy.o efi/mkreloc
$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
$(guard) $(LD) $(call EFI_LDFLAGS,$(base)) -T efi.lds -N $<
efi/relocs-dummy.o \
@@ -151,7 +172,7 @@ $(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o
$(BASEDIR)/common/symbol
| $(guard) $(BASEDIR)/tools/symbols --sysv --sort
>$(@D)/.$(@F).1s.S
$(guard) $(MAKE) -f $(BASEDIR)/Rules.mk $(@D)/.$(@F).1r.o
$(@D)/.$(@F).1s.o
$(guard) $(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T efi.lds -N $< \
- $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o -o $@
+ $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o $(build_id_file) -o
$@
if $(guard) false; then rm -f $@; echo 'EFI support disabled'; fi
rm -f $(@D)/.$(@F).[0-9]*
diff --git a/xen/arch/x86/boot/mkelf32.c b/xen/arch/x86/boot/mkelf32.c
index 890ae6d..da4347a 100644
--- a/xen/arch/x86/boot/mkelf32.c
+++ b/xen/arch/x86/boot/mkelf32.c
@@ -45,9 +45,9 @@ static Elf32_Ehdr out_ehdr = {
0, /* e_flags */
sizeof(Elf32_Ehdr), /* e_ehsize */
sizeof(Elf32_Phdr), /* e_phentsize */
- 1, /* e_phnum */
+ 1, /* modify based on num_phdrs */ /* e_phnum */
sizeof(Elf32_Shdr), /* e_shentsize */
- 3, /* e_shnum */
+ 3, /* modify based on num_phdrs */ /* e_shnum */
2 /* e_shstrndx */
};
@@ -61,8 +61,20 @@ static Elf32_Phdr out_phdr = {
PF_R|PF_W|PF_X, /* p_flags */
64 /* p_align */
};
+static Elf32_Phdr note_phdr = {
+ PT_NOTE, /* p_type */
+ DYNAMICALLY_FILLED, /* p_offset */
+ DYNAMICALLY_FILLED, /* p_vaddr */
+ DYNAMICALLY_FILLED, /* p_paddr */
+ DYNAMICALLY_FILLED, /* p_filesz */
+ DYNAMICALLY_FILLED, /* p_memsz */
+ PF_R, /* p_flags */
+ 4 /* p_align */
+};
static u8 out_shstrtab[] = "\0.text\0.shstrtab";
+/* If num_phdrs >= 2, we need to tack the .note. */
+static u8 out_shstrtab_extra[] = ".note\0";
static Elf32_Shdr out_shdr[] = {
{ 0 },
@@ -90,6 +102,23 @@ static Elf32_Shdr out_shdr[] = {
}
};
+/*
+ * The 17 points to the '.note' in the out_shstrtab and out_shstrtab_extra
+ * laid out in the file.
+ */
+static Elf32_Shdr out_shdr_extra = {
+ 17, /* sh_name */
+ SHT_NOTE, /* sh_type */
+ 0, /* sh_flags */
+ DYNAMICALLY_FILLED, /* sh_addr */
+ DYNAMICALLY_FILLED, /* sh_offset */
+ DYNAMICALLY_FILLED, /* sh_size */
+ 0, /* sh_link */
+ 0, /* sh_info */
+ 4, /* sh_addralign */
+ 0 /* sh_entsize */
+};
+
/* Some system header files define these macros and pollute our namespace. */
#undef swap16
#undef swap32
@@ -228,21 +257,22 @@ static void do_read(int fd, void *data, int len)
int main(int argc, char **argv)
{
u64 final_exec_addr;
- u32 loadbase, dat_siz, mem_siz;
+ u32 loadbase, dat_siz, mem_siz, note_base, note_sz, offset;
char *inimage, *outimage;
int infd, outfd = -1;
char buffer[1024];
int bytes, todo, i, rc = 1;
+ int num_phdrs;
Elf32_Ehdr in32_ehdr;
Elf64_Ehdr in64_ehdr;
Elf64_Phdr in64_phdr;
- if ( argc != 5 )
+ if ( argc != 6 )
{
fprintf(stderr, "Usage: mkelf32 <in-image> <out-image> "
- "<load-base> <final-exec-addr>\n");
+ "<load-base> <final-exec-addr> <number of program headers>\n");
return 1;
}
@@ -250,7 +280,13 @@ int main(int argc, char **argv)
outimage = argv[2];
loadbase = strtoul(argv[3], NULL, 16);
final_exec_addr = strtoull(argv[4], NULL, 16);
-
+ num_phdrs = atoi(argv[5]);
+ if ( num_phdrs > 2 || num_phdrs < 1 )
+ {
+ fprintf(stderr, "Number of program headers MUST be 1 or 2, got %d!\n",
+ num_phdrs);
+ return 1;
+ }
infd = open(inimage, O_RDONLY);
if ( infd == -1 )
{
@@ -285,11 +321,10 @@ int main(int argc, char **argv)
(int)in64_ehdr.e_phentsize, (int)sizeof(in64_phdr));
goto out;
}
-
- if ( in64_ehdr.e_phnum != 1 )
+ if ( in64_ehdr.e_phnum != num_phdrs )
{
- fprintf(stderr, "Expect precisly 1 program header; found %d.\n",
- (int)in64_ehdr.e_phnum);
+ fprintf(stderr, "Expect precisly %d program header; found %d.\n",
+ num_phdrs, (int)in64_ehdr.e_phnum);
goto out;
}
@@ -299,11 +334,36 @@ int main(int argc, char **argv)
(void)lseek(infd, in64_phdr.p_offset, SEEK_SET);
dat_siz = (u32)in64_phdr.p_filesz;
-
/* Do not use p_memsz: it does not include BSS alignment padding. */
/*mem_siz = (u32)in64_phdr.p_memsz;*/
mem_siz = (u32)(final_exec_addr - in64_phdr.p_vaddr);
+ note_sz = note_base = offset = 0;
+ if ( num_phdrs > 1 )
+ {
+ offset = in64_phdr.p_offset;
+ note_base = in64_phdr.p_vaddr;
+
+ (void)lseek(infd, in64_ehdr.e_phoff+sizeof(in64_phdr), SEEK_SET);
+ do_read(infd, &in64_phdr, sizeof(in64_phdr));
+ endianadjust_phdr64(&in64_phdr);
+
+ (void)lseek(infd, offset, SEEK_SET);
+
+ note_sz = in64_phdr.p_memsz;
+ note_base = in64_phdr.p_vaddr - note_base;
+
+ if ( in64_phdr.p_offset > dat_siz || offset > in64_phdr.p_offset )
+ {
+ fprintf(stderr, "Expected .note section within .text section!\n" \
+ "Offset %ld not within %d!\n",
+ in64_phdr.p_offset, dat_siz);
+ goto out;
+ }
+ /* Gets us the absolute offset within the .text section. */
+ offset = in64_phdr.p_offset - offset;
+ }
+
/*
* End the image on a page boundary. This gets round alignment bugs
* in the boot- or chain-loader (e.g., kexec on the XenoBoot CD).
@@ -322,6 +382,31 @@ int main(int argc, char **argv)
out_shdr[1].sh_size = dat_siz;
out_shdr[2].sh_offset = RAW_OFFSET + dat_siz + sizeof(out_shdr);
+ if ( num_phdrs > 1 )
+ {
+ /* We have two of them! */
+ out_ehdr.e_phnum = num_phdrs;
+ /* Extra .note section. */
+ out_ehdr.e_shnum++;
+
+ /* Fill out the PT_NOTE program header. */
+ note_phdr.p_vaddr = note_base;
+ note_phdr.p_paddr = note_base;
+ note_phdr.p_filesz = note_sz;
+ note_phdr.p_memsz = note_sz;
+ note_phdr.p_offset = offset;
+
+ /* Tack on the .note\0 */
+ out_shdr[2].sh_size += sizeof(out_shstrtab_extra);
+ /* And move it past the .note section. */
+ out_shdr[2].sh_offset += sizeof(out_shdr_extra);
+
+ /* Fill out the .note section. */
+ out_shdr_extra.sh_size = note_sz;
+ out_shdr_extra.sh_addr = note_base;
+ out_shdr_extra.sh_offset = RAW_OFFSET + offset;
+ }
+
outfd = open(outimage, O_WRONLY|O_CREAT|O_TRUNC, 0775);
if ( outfd == -1 )
{
@@ -335,8 +420,15 @@ int main(int argc, char **argv)
endianadjust_phdr32(&out_phdr);
do_write(outfd, &out_phdr, sizeof(out_phdr));
-
- if ( (bytes = RAW_OFFSET - sizeof(out_ehdr) - sizeof(out_phdr)) < 0 )
+
+ if ( num_phdrs > 1 )
+ {
+ endianadjust_phdr32(¬e_phdr);
+ do_write(outfd, ¬e_phdr, sizeof(note_phdr));
+ }
+
+ if ( (bytes = RAW_OFFSET - sizeof(out_ehdr) - sizeof(out_phdr) -
+ ( num_phdrs > 1 ? sizeof(note_phdr) : 0 ) ) < 0 )
{
fprintf(stderr, "Header overflow.\n");
goto out;
@@ -355,9 +447,22 @@ int main(int argc, char **argv)
endianadjust_shdr32(&out_shdr[i]);
do_write(outfd, &out_shdr[0], sizeof(out_shdr));
- do_write(outfd, out_shstrtab, sizeof(out_shstrtab));
- do_write(outfd, buffer, 4-((sizeof(out_shstrtab)+dat_siz)&3));
-
+ if ( num_phdrs > 1 )
+ {
+ endianadjust_shdr32(&out_shdr_extra);
+ /* Append the .note section. */
+ do_write(outfd, &out_shdr_extra, sizeof(out_shdr_extra));
+ /* The normal strings - .text\0.. */
+ do_write(outfd, out_shstrtab, sizeof(out_shstrtab));
+ /* Our .note */
+ do_write(outfd, out_shstrtab_extra, sizeof(out_shstrtab_extra));
+ do_write(outfd, buffer,
4-((sizeof(out_shstrtab)+sizeof(out_shstrtab_extra)+dat_siz)&3));
+ }
+ else
+ {
+ do_write(outfd, out_shstrtab, sizeof(out_shstrtab));
+ do_write(outfd, buffer, 4-((sizeof(out_shstrtab)+dat_siz)&3));
+ }
rc = 0;
out:
if ( infd != -1 )
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 3b199ca..99a3fcb 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -31,6 +31,9 @@ OUTPUT_ARCH(i386:x86-64)
PHDRS
{
text PT_LOAD ;
+#if defined(BUILD_ID) && !defined(EFI)
+ note PT_NOTE ;
+#endif
}
SECTIONS
{
@@ -67,6 +70,21 @@ SECTIONS
*(.rodata.*)
} :text
+#if defined(BUILD_ID) && !defined(EFI)
+/*
+ * No mechanism to put an PT_NOTE in the EFI file - so put
+ * it in .data section.
+ */
+ . = ALIGN(4);
+ .note : {
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+ *(.note)
+ *(.note.*)
+ } :note :text
+#endif
+
. = ALIGN(SMP_CACHE_BYTES);
.data.read_mostly : {
/* Exception table */
@@ -86,6 +104,11 @@ SECTIONS
__end_schedulers_array = .;
*(.data.rel.ro)
*(.data.rel.ro.*)
+#if defined(BUILD_ID) && defined(EFI)
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+#endif
} :text
.data : { /* Data */
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index a5e3f0e..cd746a9 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -383,6 +383,42 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
return -EFAULT;
return 0;
}
+
+ case XENVER_build_id:
+ {
+ xen_build_id_t build_id;
+ unsigned int sz = 0;
+ int rc = 0;
+ char *p = NULL;
+
+ if ( deny )
+ return -EPERM;
+
+ /* Only return size. */
+ if ( !guest_handle_is_null(arg) )
+ {
+ if ( copy_from_guest(&build_id, arg, 1) )
+ return -EFAULT;
+
+ if ( build_id.len == 0 )
+ return -EINVAL;
+ }
+
+ rc = xen_build_id(&p, &sz);
+ if ( rc )
+ return rc;
+
+ if ( guest_handle_is_null(arg) )
+ return sz;
+
+ if ( sz > build_id.len )
+ return -ENOBUFS;
+
+ if ( copy_to_guest_offset(arg, offsetof(xen_build_id_t, buf), p, sz) )
+ return -EFAULT;
+
+ return sz;
+ }
}
return -ENOSYS;
diff --git a/xen/common/version.c b/xen/common/version.c
index 786be4e..33c09e5 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -1,5 +1,9 @@
#include <xen/compile.h>
+#include <xen/errno.h>
+#include <xen/string.h>
+#include <xen/types.h>
#include <xen/version.h>
+#include <xen/elf.h>
const char *xen_compile_date(void)
{
@@ -60,3 +64,47 @@ const char *xen_deny(void)
{
return "<denied>";
}
+#ifdef BUILD_ID
+#define NT_GNU_BUILD_ID 3
+/* Defined in linker script. */
+extern const Elf_Note __note_gnu_build_id_start[], __note_gnu_build_id_end[];
+
+int xen_build_id(char **p, unsigned int *len)
+{
+ const Elf_Note *n = __note_gnu_build_id_start;
+ static bool_t checked = 0;
+
+ if ( checked )
+ {
+ *len = n->descsz;
+ *p = ELFNOTE_DESC(n);
+ return 0;
+ }
+ /* --build-id invoked with wrong parameters. */
+ if ( __note_gnu_build_id_end <= __note_gnu_build_id_start )
+ return -ENODATA;
+
+ /* Check for full Note header. */
+ if ( &n[1] > __note_gnu_build_id_end )
+ return -ENODATA;
+
+ /* Check if we really have a build-id. */
+ if ( NT_GNU_BUILD_ID != n->type )
+ return -ENODATA;
+
+ /* Sanity check, name should be "GNU" for ld-generated build-id. */
+ if ( strncmp(ELFNOTE_NAME(n), "GNU", n->namesz) != 0 )
+ return -ENODATA;
+
+ *len = n->descsz;
+ *p = ELFNOTE_DESC(n);
+
+ checked = 1;
+ return 0;
+}
+#else
+int xen_build_id(char **p, unsigned int *len)
+{
+ return -ENODATA;
+}
+#endif
diff --git a/xen/include/public/version.h b/xen/include/public/version.h
index 44f26b0..adca602 100644
--- a/xen/include/public/version.h
+++ b/xen/include/public/version.h
@@ -30,7 +30,8 @@
#include "xen.h"
-/* NB. All ops return zero on success, except XENVER_{version,pagesize} */
+/* NB. All ops return zero on success, except
+ * XENVER_{version,pagesize,build_id} */
/* arg == NULL; returns major:minor (16:16). */
#define XENVER_version 0
@@ -83,6 +84,19 @@ typedef struct xen_feature_info xen_feature_info_t;
#define XENVER_commandline 9
typedef char xen_commandline_t[1024];
+/* Return value is the number of bytes written, or XEN_Exx on error.
+ * Calling with empty parameter returns the size of build_id. */
+#define XENVER_build_id 10
+struct xen_build_id {
+ uint32_t len; /* IN: size of buf[]. */
+#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
+ unsigned char buf[];
+#elif defined(__GNUC__)
+ unsigned char buf[1]; /* OUT: Variable length buffer with build_id.
*/
+#endif
+};
+typedef struct xen_build_id xen_build_id_t;
+
#endif /* __XEN_PUBLIC_VERSION_H__ */
/*
diff --git a/xen/include/xen/version.h b/xen/include/xen/version.h
index 2015c0b..466c977 100644
--- a/xen/include/xen/version.h
+++ b/xen/include/xen/version.h
@@ -13,5 +13,6 @@ const char *xen_extra_version(void);
const char *xen_changeset(void);
const char *xen_banner(void);
const char *xen_deny(void);
+int xen_build_id(char **p, unsigned int *len);
#endif /* __XEN_VERSION_H__ */
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 7e3bcdd..396ee46 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -1664,6 +1664,9 @@ static int flask_version_op (uint32_t op)
case XENVER_commandline:
return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
VERSION__COMMANDLINE, NULL);
+ case XENVER_build_id:
+ return avc_has_perm(dsid, SECINITSID_XEN, SECCLASS_VERSION,
+ VERSION__BUILD_ID, NULL);
default:
return -EPERM;
}
diff --git a/xen/xsm/flask/policy/access_vectors
b/xen/xsm/flask/policy/access_vectors
index 7cb32de..c9cd102 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -524,4 +524,6 @@ class version
guest_handle
# Xen command line.
commandline
+# Build id
+ build_id
}
--
2.1.0
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