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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 2/3] XENVER_build_id: Provide ld-embedded build-ids
From: Martin Pohlack <mpohlack@xxxxxxxxx>
The mechanism to get this is via the XENVER_build_id and
we add a new subsequent sub-command to retrieve the
binary build-id. The hypercall allows an arbitrary
size (the buffer and len is provided to the hypervisor).
Note that one can also retrieve the value by 'readelf -h xen-syms'.
For EFI builds we re-use the same build-id that the xen-syms
was built with.
Note that there are no changes to the XSM files (dummy.c
and hooks.c) as the priviliged subops fall in the default case.
Since the new sub-ops provides the len parameter in the
arguments to the hypercall we have to modify libxc to allow
copying the arguments before the hypercall. We provide a
new macro that modifies the bounce structure to change
the direction.
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.
---
tools/libxc/xc_private.c | 7 +++++++
tools/libxc/xc_private.h | 10 ++++++++++
xen/arch/x86/Makefile | 14 +++++++++-----
xen/arch/x86/xen.lds.S | 6 ++++++
xen/common/kernel.c | 29 +++++++++++++++++++++++++++++
xen/common/version.c | 36 ++++++++++++++++++++++++++++++++++++
xen/include/public/version.h | 15 ++++++++++++++-
xen/include/xen/version.h | 1 +
xen/xsm/flask/policy/access_vectors | 2 +-
9 files changed, 113 insertions(+), 7 deletions(-)
diff --git a/tools/libxc/xc_private.c b/tools/libxc/xc_private.c
index 7c39897..9cd676e 100644
--- a/tools/libxc/xc_private.c
+++ b/tools/libxc/xc_private.c
@@ -712,6 +712,13 @@ 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 2df1d59..aa0cad7 100644
--- a/tools/libxc/xc_private.h
+++ b/tools/libxc/xc_private.h
@@ -202,6 +202,16 @@ 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/x86/Makefile b/xen/arch/x86/Makefile
index d4e507a..17a4830 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -109,15 +109,19 @@ $(TARGET)-syms: prelink.o xen.lds
$(BASEDIR)/common/symbols-dummy.o
$(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 --build-id=sha1 \
$(@D)/.$(@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=sha1 \
$(@D)/.$(@F).1.o -o $@
rm -f $(@D)/.$(@F).[0-9]*
+build_id.o: $(TARGET)-syms
+ $(OBJCOPY) --only-section=.note.gnu.build-id $< build_id.o
+
+
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
@@ -130,7 +134,7 @@ $(TARGET).efi: VIRT_BASE = 0x$(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 $(shell echo efi/dis* | grep disabled),:)
-$(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o
$(BASEDIR)/common/symbols-dummy.o efi/mkreloc
+$(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o
$(BASEDIR)/common/symbols-dummy.o efi/mkreloc build_id.o
$(foreach base, $(VIRT_BASE) $(ALT_BASE), \
$(guard) $(LD) $(call EFI_LDFLAGS,$(base)) -T efi.lds -N $<
efi/relocs-dummy.o \
$(BASEDIR)/common/symbols-dummy.o -o
$(@D)/.$(@F).$(base).0 &&) :
@@ -145,8 +149,8 @@ $(TARGET).efi: prelink-efi.o efi.lds efi/relocs-dummy.o
$(BASEDIR)/common/symbol
$(guard) $(NM) -pa --format=sysv $(@D)/.$(@F).$(VIRT_BASE).1 \
| $(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 $@
+ $(guard) $(LD) $(call EFI_LDFLAGS,$(VIRT_BASE)) -T efi.lds
--build-id=sha1 -N $< \
+ $(@D)/.$(@F).1r.o $(@D)/.$(@F).1s.o build_id.o -o $@
if $(guard) false; then rm -f $@; echo 'EFI support disabled'; fi
rm -f $(@D)/.$(@F).[0-9]*
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 6553cff..c4aabc3 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -67,6 +67,12 @@ SECTIONS
*(.rodata.*)
} :text
+ .note.gnu.build-id : {
+ __note_gnu_build_id_start = .;
+ *(.note.gnu.build-id)
+ __note_gnu_build_id_end = .;
+ } :text
+
. = ALIGN(SMP_CACHE_BYTES);
.data.read_mostly : {
/* Exception table */
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index d51a3ed..1574c63 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -366,6 +366,35 @@ 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;
+ int rc = 0;
+ char *p = NULL;
+
+ if ( deny )
+ return -EPERM;
+
+ 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 ( sz > build_id.len )
+ return -ENOMEM;
+
+ if ( copy_to_guest_offset(arg, offsetof(xen_build_id_t, buf),
+ deny ? xen_deny() : p, sz) )
+ return -EFAULT;
+
+ return sz;
+ }
}
return -ENOSYS;
diff --git a/xen/common/version.c b/xen/common/version.c
index 786be4e..d556c35 100644
--- a/xen/common/version.c
+++ b/xen/common/version.c
@@ -1,5 +1,9 @@
#include <xen/compile.h>
#include <xen/version.h>
+#include <xen/types.h>
+#include <xen/string.h>
+#include <xen/elf.h>
+#include <xen/errno.h>
const char *xen_compile_date(void)
{
@@ -60,3 +64,35 @@ const char *xen_deny(void)
{
return "<denied>";
}
+#ifdef CONFIG_ARM
+int xen_build_id(char **p, unsigned int *len)
+{
+ return -ENODATA;
+}
+#else
+#define NT_GNU_BUILD_ID 3
+
+extern const Elf_Note __note_gnu_build_id_start; /* Defined in linker script.
*/
+extern const char __note_gnu_build_id_end[];
+int xen_build_id(char **p, unsigned int *len)
+{
+ const Elf_Note *n = &__note_gnu_build_id_start;
+
+ /* Something is wrong. */
+ if ( __note_gnu_build_id_end <= (char *)&__note_gnu_build_id_start )
+ 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);
+
+ return 0;
+}
+#endif
diff --git a/xen/include/public/version.h b/xen/include/public/version.h
index 44f26b0..adae298 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 +84,18 @@ typedef struct xen_feature_info xen_feature_info_t;
#define XENVER_commandline 9
typedef char xen_commandline_t[1024];
+/* arg = xen_build_id_t. Returns size in bytes or XEN_Exx. */
+#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/policy/access_vectors
b/xen/xsm/flask/policy/access_vectors
index 273459f..35bdb42 100644
--- a/xen/xsm/flask/policy/access_vectors
+++ b/xen/xsm/flask/policy/access_vectors
@@ -93,7 +93,7 @@ class xen2
pmu_ctrl
# PMU use (domains, including unprivileged ones, will be using this operation)
pmu_use
-# XENVER_[compile_info|changeset|commandline|extraversion] usage.
+# XENVER_[compile_info|changeset|commandline|extraversion|buildid] usage.
version_priv
}
--
2.1.0
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