From: Chris Kennelly <ckennelly@google.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
Song Liu <songliubraving@fb.com>
Cc: David Rientjes <rientjes@google.com>,
Ian Rogers <irogers@google.com>, Hugh Dickens <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Suren Baghdasaryan <surenb@google.com>,
Sandeep Patil <sspatil@google.com>,
Fangrui Song <maskray@google.com>,
Nick Desaulniers <ndesaulniers@google.com>,
clang-built-linux@googlegroups.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Chris Kennelly <ckennelly@google.com>
Subject: [PATCH v3 2/2] Add self-test for verifying load alignment.
Date: Thu, 20 Aug 2020 13:05:41 -0400 [thread overview]
Message-ID: <20200820170541.1132271-3-ckennelly@google.com> (raw)
In-Reply-To: <20200820170541.1132271-1-ckennelly@google.com>
This produces a PIE binary with a variety of p_align requirements,
suitable for verifying that the load address meets that alignment
requirement.
Signed-off-by: Chris Kennelly <ckennelly@google.com>
---
tools/testing/selftests/exec/.gitignore | 1 +
tools/testing/selftests/exec/Makefile | 9 ++-
tools/testing/selftests/exec/load_address.c | 68 +++++++++++++++++++++
3 files changed, 76 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/exec/load_address.c
diff --git a/tools/testing/selftests/exec/.gitignore b/tools/testing/selftests/exec/.gitignore
index 344a99c6da1b7..9e2f00343f15f 100644
--- a/tools/testing/selftests/exec/.gitignore
+++ b/tools/testing/selftests/exec/.gitignore
@@ -7,6 +7,7 @@ execveat.moved
execveat.path.ephemeral
execveat.ephemeral
execveat.denatured
+/load_address_*
/recursion-depth
xxxxxxxx*
pipe
diff --git a/tools/testing/selftests/exec/Makefile b/tools/testing/selftests/exec/Makefile
index 0a13b110c1e66..cf69b2fcce59e 100644
--- a/tools/testing/selftests/exec/Makefile
+++ b/tools/testing/selftests/exec/Makefile
@@ -4,7 +4,7 @@ CFLAGS += -Wno-nonnull
CFLAGS += -D_GNU_SOURCE
TEST_PROGS := binfmt_script non-regular
-TEST_GEN_PROGS := execveat
+TEST_GEN_PROGS := execveat load_address_4096 load_address_2097152 load_address_16777216
TEST_GEN_FILES := execveat.symlink execveat.denatured script subdir pipe
# Makefile is a run-time dependency, since it's accessed by the execveat test
TEST_FILES := Makefile
@@ -27,4 +27,9 @@ $(OUTPUT)/execveat.symlink: $(OUTPUT)/execveat
$(OUTPUT)/execveat.denatured: $(OUTPUT)/execveat
cp $< $@
chmod -x $@
-
+$(OUTPUT)/load_address_4096: load_address.c
+ $(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x1000 -pie $< -o $@
+$(OUTPUT)/load_address_2097152: load_address.c
+ $(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x200000 -pie $< -o $@
+$(OUTPUT)/load_address_16777216: load_address.c
+ $(CC) $(CFLAGS) $(LDFLAGS) -Wl,-z,max-page-size=0x1000000 -pie $< -o $@
diff --git a/tools/testing/selftests/exec/load_address.c b/tools/testing/selftests/exec/load_address.c
new file mode 100644
index 0000000000000..d487c2f6a6150
--- /dev/null
+++ b/tools/testing/selftests/exec/load_address.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <link.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+struct Statistics {
+ unsigned long long load_address;
+ unsigned long long alignment;
+};
+
+int ExtractStatistics(struct dl_phdr_info *info, size_t size, void *data)
+{
+ struct Statistics *stats = (struct Statistics *) data;
+ int i;
+
+ if (info->dlpi_name != NULL && info->dlpi_name[0] != '\0') {
+ // Ignore headers from other than the executable.
+ return 2;
+ }
+
+ stats->load_address = (unsigned long long) info->dlpi_addr;
+ stats->alignment = 0;
+
+ for (i = 0; i < info->dlpi_phnum; i++) {
+ if (info->dlpi_phdr[i].p_type != PT_LOAD)
+ continue;
+
+ if (info->dlpi_phdr[i].p_align > stats->alignment)
+ stats->alignment = info->dlpi_phdr[i].p_align;
+ }
+
+ return 1; // Terminate dl_iterate_phdr.
+}
+
+int main(int argc, char **argv)
+{
+ struct Statistics extracted;
+ unsigned long long misalign;
+ int ret;
+
+ ret = dl_iterate_phdr(ExtractStatistics, &extracted);
+ if (ret != 1) {
+ fprintf(stderr, "FAILED\n");
+ return 1;
+ }
+
+ if (extracted.alignment == 0) {
+ fprintf(stderr, "No alignment found\n");
+ return 1;
+ } else if (extracted.alignment & (extracted.alignment - 1)) {
+ fprintf(stderr, "Alignment is not a power of 2\n");
+ return 1;
+ }
+
+ misalign = extracted.load_address & (extracted.alignment - 1);
+ if (misalign) {
+ printf("alignment = %llu, load_address = %llu\n",
+ extracted.alignment, extracted.load_address);
+ fprintf(stderr, "FAILED\n");
+ return 1;
+ }
+
+ fprintf(stderr, "PASS\n");
+ return 0;
+}
--
2.28.0.297.g1956fa8f8d-goog
prev parent reply other threads:[~2020-08-20 17:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 17:05 [PATCH v3 0/2] Selecting Load Addresses According to p_align Chris Kennelly
2020-08-20 17:05 ` [PATCH v3 1/2] fs/binfmt_elf: Use PT_LOAD p_align values for suitable start address Chris Kennelly
2020-08-21 3:51 ` Andrew Morton
2020-08-20 17:05 ` Chris Kennelly [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200820170541.1132271-3-ckennelly@google.com \
--to=ckennelly@google.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=clang-built-linux@googlegroups.com \
--cc=hughd@google.com \
--cc=irogers@google.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maskray@google.com \
--cc=ndesaulniers@google.com \
--cc=rientjes@google.com \
--cc=songliubraving@fb.com \
--cc=sspatil@google.com \
--cc=surenb@google.com \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).