[PATCH] libebl: Handle aarch64 bti, pac bits in gnu property note
Mark Wielaard
mark@klomp.org
Thu Sep 3 09:56:15 GMT 2020
When building with gcc -mbranch-protection= we might get a gnu property
note indicating BTI (Branch Target Identification) and/or PAC (Pointer
Authentication Code) is being used.
Add a small testcase to show eu-readelf -n now properly lists those
bits in the gnu property note.
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
libebl/ChangeLog | 5 ++
libebl/eblobjnote.c | 67 +++++++++++++++++++
tests/ChangeLog | 5 ++
tests/run-readelf-n.sh | 31 +++++++++
tests/testfile-gnu-property-note-aarch64.bz2 | Bin 0 -> 1952 bytes
5 files changed, 108 insertions(+)
create mode 100755 tests/testfile-gnu-property-note-aarch64.bz2
diff --git a/libebl/ChangeLog b/libebl/ChangeLog
index e54aa2c9..aa43b31f 100644
--- a/libebl/ChangeLog
+++ b/libebl/ChangeLog
@@ -1,3 +1,8 @@
+2020-09-03 Mark Wielaard <mark@klomp.org>
+
+ * eblobjnote.c (ebl_object_note): For EM_AARCH64 handle BTI and PAC
+ in GNU_PROPERTY_AARCH64_FEATURE_1_AND.
+
2020-07-19 Mark Wielaard <mark@klomp.org>
* libebl.h: Only typedef Ebl if _LIBASM_H is undefined.
diff --git a/libebl/eblobjnote.c b/libebl/eblobjnote.c
index f7ac915c..37cbc499 100644
--- a/libebl/eblobjnote.c
+++ b/libebl/eblobjnote.c
@@ -476,6 +476,73 @@ ebl_object_note (Ebl *ebl, uint32_t namesz, const char *name, uint32_t type,
}
}
}
+ else if (prop.pr_type >= GNU_PROPERTY_LOPROC
+ && prop.pr_type <= GNU_PROPERTY_HIPROC
+ && ehdr.e_machine == EM_AARCH64)
+ {
+ printf ("AARCH64 ");
+ if (prop.pr_type == GNU_PROPERTY_AARCH64_FEATURE_1_AND)
+ {
+ printf ("FEATURE_1_AND: ");
+
+ if (prop.pr_datasz == 4)
+ {
+ GElf_Word data;
+ in.d_type = ELF_T_WORD;
+ out.d_type = ELF_T_WORD;
+ in.d_size = 4;
+ out.d_size = 4;
+ in.d_buf = (void *) desc;
+ out.d_buf = (void *) &data;
+
+ if (gelf_xlatetom (ebl->elf, &out, &in,
+ elfident[EI_DATA]) == NULL)
+ {
+ printf ("%s\n", elf_errmsg (-1));
+ return;
+ }
+ printf ("%08" PRIx32 " ", data);
+
+ if ((data & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
+ != 0)
+ {
+ printf ("BTI");
+ data &= ~GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
+ if (data != 0)
+ printf (" ");
+ }
+
+ if ((data & GNU_PROPERTY_AARCH64_FEATURE_1_PAC)
+ != 0)
+ {
+ printf ("PAC");
+ data &= ~GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
+ if (data != 0)
+ printf (" ");
+ }
+
+ if (data != 0)
+ printf ("UNKNOWN");
+ }
+ else
+ printf ("<bad datasz: %" PRId32 ">",
+ prop.pr_datasz);
+
+ printf ("\n");
+ }
+ else
+ {
+ printf ("%#" PRIx32, prop.pr_type);
+ if (prop.pr_datasz > 0)
+ {
+ printf (" data: ");
+ size_t i;
+ for (i = 0; i < prop.pr_datasz - 1; i++)
+ printf ("%02" PRIx8 " ", (uint8_t) desc[i]);
+ printf ("%02" PRIx8 "\n", (uint8_t) desc[i]);
+ }
+ }
+ }
else
{
if (prop.pr_type >= GNU_PROPERTY_LOPROC
diff --git a/tests/ChangeLog b/tests/ChangeLog
index 047100b0..cb2e9956 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,8 @@
+2020-09-03 Mark Wielaard <mark@klomp.org>
+
+ * testfile-gnu-property-note-aarch64.bz2: New file.
+ * run-readelf-n.sh: Handle testfile-gnu-property-note-aarch64.
+
2020-07-19 Mark Wielaard <mark@klomp.org>
* asm-tst1.c: Include libebl.h after libasm.h.
diff --git a/tests/run-readelf-n.sh b/tests/run-readelf-n.sh
index cc7d7f66..4c98fd82 100755
--- a/tests/run-readelf-n.sh
+++ b/tests/run-readelf-n.sh
@@ -226,3 +226,34 @@ Note section [ 4] '.note.gnu.property' of 56 bytes at offset 0x40:
GNU 8 GNU_PROPERTY_TYPE_0
NO_COPY_ON_PROTECTION
EOF
+
+# - testfile-gnu-property-note.c
+# int
+# main ()
+# {
+# return 0;
+# }
+#
+# gcc -mbranch-protection=standard -c testfile-gnu-property-note.c
+# gcc -o testfile-gnu-property-note-aarch64 testfile-gnu-property-note.o
+# eu-strip --remove-section=.gnu.build.attributes \
+# testfile-gnu-property-note-aarch64
+
+testfiles testfile-gnu-property-note-aarch64
+testrun_compare ${abs_top_builddir}/src/readelf -n testfile-gnu-property-note-aarch64 << EOF
+
+Note section [ 2] '.note.gnu.property' of 32 bytes at offset 0x2c8:
+ Owner Data size Type
+ GNU 16 GNU_PROPERTY_TYPE_0
+ AARCH64 FEATURE_1_AND: 00000003 BTI PAC
+
+Note section [ 3] '.note.gnu.build-id' of 36 bytes at offset 0x2e8:
+ Owner Data size Type
+ GNU 20 GNU_BUILD_ID
+ Build ID: af82d6df6f3b396487e3e27a826ca9cbbbecbe5f
+
+Note section [ 4] '.note.ABI-tag' of 32 bytes at offset 0x30c:
+ Owner Data size Type
+ GNU 16 GNU_ABI_TAG
+ OS: Linux, ABI: 3.7.0
+EOF
diff --git a/tests/testfile-gnu-property-note-aarch64.bz2 b/tests/testfile-gnu-property-note-aarch64.bz2
new file mode 100755
index 0000000000000000000000000000000000000000..2fe37b1957065c4ebeb5ffae4c933fe7da1310b6
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--
2.18.4
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