libebl: Handle aarch64 bti, pac bits in gnu property note

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>

6 files changed, 111 insertions, 0 deletions

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..61c6cb7c 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,3 +1,10 @@
+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.
+	* Makefile.am (EXTRA_DIST): Add
+	testfile-gnu-property-note-aarch64.bz2.
+
 2020-07-19  Mark Wielaard  <mark@klomp.org>
 
 	* asm-tst1.c: Include libebl.h after libasm.h.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index d30b8218..939bbb6a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -319,6 +319,7 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh run-ar.sh \
 	     testfile_gnu_props.64le.o.bz2 \
 	     testfile_gnu_props.32be.o.bz2 \
 	     testfile_gnu_props.64be.o.bz2 \
+	     testfile-gnu-property-note-aarch64.bz2 \
 	     run-allfcts-multi.sh \
 	     test-offset-loop.bz2 test-offset-loop.alt.bz2 \
 	     run-prelink-addr-test.sh \
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 00000000..2fe37b19
--- /dev/null
+++ b/tests/testfile-gnu-property-note-aarch64.bz2