I've added the x86 ISA requirement too, since that's the other one I see
on my (host!) system, but I'm really just here for arm64 PAC/BTI. There
are others, but YAGNI.
Also remove incorrect TODO comments: j is implicitly non-zero from the
loop (so we _could_ add `, j=1` but it seems redundant), and notematch()
doesn't advance the pointer unless it matches (like strstart()).
---
toys/other/readelf.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
From 2c5fcff3710cdd4fc2f9f36eb891494e0d88c273 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <e...@google.com>
Date: Tue, 8 Aug 2023 13:33:53 -0700
Subject: [PATCH] readelf: add PAC and BTI decoding.
I've added the x86 ISA requirement too, since that's the other one I see
on my (host!) system, but I'm really just here for arm64 PAC/BTI. There
are others, but YAGNI.
Also remove incorrect TODO comments: j is implicitly non-zero from the
loop (so we _could_ add `, j=1` but it seems redundant), and notematch()
doesn't advance the pointer unless it matches (like strstart()).
---
toys/other/readelf.c | 31 ++++++++++++++++++++++++++++---
1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/toys/other/readelf.c b/toys/other/readelf.c
index 91d92272..54e6e22c 100644
--- a/toys/other/readelf.c
+++ b/toys/other/readelf.c
@@ -319,11 +319,38 @@ static void show_notes(unsigned long offset, unsigned long size)
printf("NT_GNU_ABI_TAG\tOS: %s, ABI: %u.%u.%u",
!elf_int(&p)?"Linux":"?", elf_int(&p), elf_int(&p), elf_int(&p)), j=1;
} else if (type == 3) {
-// TODO should this set j=1?
printf("NT_GNU_BUILD_ID\t");
for (;j<descsz;j++) printf("%02x", *p++);
} else if (type == 4) {
printf("NT_GNU_GOLD_VERSION\t%.*s", descsz, p), j=1;
+ } else if (type == 5) {
+ printf("NT_GNU_PROPERTY_TYPE_0\t");
+ while (descsz-j > 8) { // Ignore 0-padding at the end.
+ int pr_type = elf_int(&p);
+ int pr_size = elf_int(&p), k, pr_data;
+
+ j += 8;
+ printf("\n Properties: ");
+ if (pr_size != 4) {
+ // Just hex dump anything we aren't familiar with.
+ for (k=0;k<pr_size;k++) printf("%02x", *p++);
+ xputc('\n');
+ j += pr_size;
+ } else {
+ pr_data = elf_int(&p);
+ j += 4;
+ if (pr_type == 0xc0000000) {
+ printf("arm64 features:");
+ if (pr_data & 1) printf(" bti");
+ if (pr_data & 2) printf(" pac");
+ xputc('\n');
+ } else if (pr_type == 0xc0008002) {
+ printf("x86 isa needed: x86-64v%d", ffs(pr_data));
+ } else {
+ printf("other (%#x): %#x", pr_type, pr_data);
+ }
+ }
+ }
} else p -= 4;
} else if (notematch(namesz, &p, "Android")) {
if (type == 1) {
@@ -332,10 +359,8 @@ static void show_notes(unsigned long offset, unsigned long size)
} else p -= 8;
} else if (notematch(namesz, &p, "CORE")) {
if (*(desc = nt_type_core(type)) != '0') printf("%s", desc), j=1;
-// TODO else p -= 5?
} else if (notematch(namesz, &p, "LINUX")) {
if (*(desc = nt_type_linux(type)) != '0') printf("%s", desc), j=1;
-// TODO else p -= 6?
}
// If we didn't do custom output above, show a hex dump.
--
2.41.0.640.ga95def55d0-goog
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