From: Thomas Garnier <thgarnie@google.com>
To: "Herbert Xu" <herbert@gondor.apana.org.au>,
"David S . Miller" <davem@davemloft.net>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>,
"Peter Zijlstra" <peterz@infradead.org>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Kate Stewart" <kstewart@linuxfoundation.org>,
"Thomas Garnier" <thgarnie@google.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Philippe Ombredanne" <pombredanne@nexb.com>,
"Arnaldo Carvalho de Melo" <acme@redhat.com>,
"Andrey Ryabinin" <aryabinin@virtuozzo.com>,
"Matthias Kaehlcke" <mka@chromium.org>,
"Kees Cook" <keescook@chromium.org>,
"Tom Lendacky" <thomas.lendacky@amd.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Dominik Brodowski" <linux@dominikbrodowski.net>,
"Borislav Petkov" <bp@alien8.de>, "Borislav Petkov" <bp@suse.de>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
"Len Brown" <len.brown@intel.com>, "Pavel Machek" <pavel@ucw.cz>,
"Juergen Gross" <jgross@suse.com>,
"Alok Kataria" <akataria@vmware.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Tejun Heo" <tj@kernel.org>, "Christoph Lameter" <cl@linux.com>,
"Dennis Zhou" <dennisszhou@gmail.com>,
"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
"David Woodhouse" <dwmw@amazon.co.uk>,
"Alexey Dobriyan" <adobriyan@gmail.com>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Nicolas Pitre" <nicolas.pitre@linaro.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Luis R . Rodriguez" <mcgrof@kernel.org>,
"Christopher Li" <sparse@chrisli.org>,
"Jason Baron" <jbaron@akamai.com>,
"Ashish Kalra" <ashish@bluestacks.com>,
"Kyle McMartin" <kyle@redhat.com>,
"Dou Liyang" <douly.fnst@cn.fujitsu.com>,
"Lukas Wunner" <lukas@wunner.de>,
"Petr Mladek" <pmladek@suse.com>,
"Sergey Senozhatsky" <sergey.senozhatsky.work@gmail.com>,
"Masahiro Yamada" <yamada.masahiro@socionext.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Cao jin" <caoj.fnst@cn.fujitsu.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Joerg Roedel" <joro@8bytes.org>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Rik van Riel" <riel@redhat.com>,
"Jia Zhang" <qianyue.zj@alibaba-inc.com>,
"Jiri Slaby" <jslaby@suse.cz>, "Kyle Huey" <me@kylehuey.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Matthew Wilcox" <mawilcox@microsoft.com>,
"Michal Hocko" <mhocko@suse.com>, "Rob Landley" <rob@landley.net>,
"Baoquan He" <bhe@redhat.com>,
"Daniel Micay" <danielmicay@gmail.com>,
"Jan H . Schönherr" <jschoenh@amazon.de>
Cc: x86@kernel.org, linux-crypto@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
xen-devel@lists.xenproject.org, linux-arch@vger.kernel.org,
linux-sparse@vger.kernel.org, kvm@vger.kernel.org,
linux-doc@vger.kernel.org, kernel-hardening@lists.openwall.com
Subject: [PATCH v2 17/27] x86/relocs: Handle PIE relocations
Date: Tue, 13 Mar 2018 13:59:35 -0700 [thread overview]
Message-ID: <20180313205945.245105-18-thgarnie@google.com> (raw)
In-Reply-To: <20180313205945.245105-1-thgarnie@google.com>
Change the relocation tool to correctly handle relocations generated by
-fPIE option:
- Add relocation for each entry of the .got section given the linker does not
generate R_X86_64_GLOB_DAT on a simple link.
- Ignore R_X86_64_GOTPCREL.
Signed-off-by: Thomas Garnier <thgarnie@google.com>
---
arch/x86/tools/relocs.c | 93 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 92 insertions(+), 1 deletion(-)
diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 220e97841e49..a35cc337f883 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -32,6 +32,7 @@ struct section {
Elf_Sym *symtab;
Elf_Rel *reltab;
char *strtab;
+ Elf_Addr *got;
};
static struct section *secs;
@@ -293,6 +294,35 @@ static Elf_Sym *sym_lookup(const char *symname)
return 0;
}
+static Elf_Sym *sym_lookup_addr(Elf_Addr addr, const char **name)
+{
+ int i;
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ long nsyms;
+ Elf_Sym *symtab;
+ Elf_Sym *sym;
+
+ if (sec->shdr.sh_type != SHT_SYMTAB)
+ continue;
+
+ nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
+ symtab = sec->symtab;
+
+ for (sym = symtab; --nsyms >= 0; sym++) {
+ if (sym->st_value == addr) {
+ if (name) {
+ *name = sym_name(sec->link->strtab,
+ sym);
+ }
+ return sym;
+ }
+ }
+ }
+ return 0;
+}
+
+
#if BYTE_ORDER == LITTLE_ENDIAN
#define le16_to_cpu(val) (val)
#define le32_to_cpu(val) (val)
@@ -513,6 +543,33 @@ static void read_relocs(FILE *fp)
}
}
+static void read_got(FILE *fp)
+{
+ int i;
+ for (i = 0; i < ehdr.e_shnum; i++) {
+ struct section *sec = &secs[i];
+ sec->got = NULL;
+ if (sec->shdr.sh_type != SHT_PROGBITS ||
+ strcmp(sec_name(i), ".got")) {
+ continue;
+ }
+ sec->got = malloc(sec->shdr.sh_size);
+ if (!sec->got) {
+ die("malloc of %d bytes for got failed\n",
+ sec->shdr.sh_size);
+ }
+ if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
+ die("Seek to %d failed: %s\n",
+ sec->shdr.sh_offset, strerror(errno));
+ }
+ if (fread(sec->got, 1, sec->shdr.sh_size, fp)
+ != sec->shdr.sh_size) {
+ die("Cannot read got: %s\n",
+ strerror(errno));
+ }
+ }
+}
+
static void print_absolute_symbols(void)
{
@@ -643,6 +700,32 @@ static void add_reloc(struct relocs *r, uint32_t offset)
r->offset[r->count++] = offset;
}
+/*
+ * The linker does not generate relocations for the GOT for the kernel.
+ * If a GOT is found, simulate the relocations that should have been included.
+ */
+static void walk_got_table(int (*process)(struct section *sec, Elf_Rel *rel,
+ Elf_Sym *sym, const char *symname),
+ struct section *sec)
+{
+ int i;
+ Elf_Addr entry;
+ Elf_Sym *sym;
+ const char *symname;
+ Elf_Rel rel;
+
+ for (i = 0; i < sec->shdr.sh_size/sizeof(Elf_Addr); i++) {
+ entry = sec->got[i];
+ sym = sym_lookup_addr(entry, &symname);
+ if (!sym)
+ die("Could not found got symbol for entry %d\n", i);
+ rel.r_offset = sec->shdr.sh_addr + i * sizeof(Elf_Addr);
+ rel.r_info = ELF_BITS == 64 ? R_X86_64_GLOB_DAT
+ : R_386_GLOB_DAT;
+ process(sec, &rel, sym, symname);
+ }
+}
+
static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
Elf_Sym *sym, const char *symname))
{
@@ -656,6 +739,8 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
struct section *sec = &secs[i];
if (sec->shdr.sh_type != SHT_REL_TYPE) {
+ if (sec->got)
+ walk_got_table(process, sec);
continue;
}
sec_symtab = sec->link;
@@ -765,6 +850,7 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
offset += per_cpu_load_addr;
switch (r_type) {
+ case R_X86_64_GOTPCREL:
case R_X86_64_NONE:
/* NONE can be ignored. */
break;
@@ -809,7 +895,7 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
* the relocations are processed.
* Make sure that the offset will fit.
*/
- if ((int32_t)offset != (int64_t)offset)
+ if (r_type != R_X86_64_64 && (int32_t)offset != (int64_t)offset)
die("Relocation offset doesn't fit in 32 bits\n");
if (r_type == R_X86_64_64)
@@ -818,6 +904,10 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
add_reloc(&relocs32, offset);
break;
+ case R_X86_64_GLOB_DAT:
+ add_reloc(&relocs64, offset);
+ break;
+
default:
die("Unsupported relocation type: %s (%d)\n",
rel_type(r_type), r_type);
@@ -1087,6 +1177,7 @@ void process(FILE *fp, int use_real_mode, int as_text,
read_strtabs(fp);
read_symtabs(fp);
read_relocs(fp);
+ read_got(fp);
if (ELF_BITS == 64)
percpu_init();
if (show_absolute_syms) {
--
2.16.2.660.g709887971b-goog
next prev parent reply other threads:[~2018-03-13 20:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-13 20:59 [PATCH v2 00/27] x86: PIE support and option to extend KASLR randomization Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 01/27] x86/crypto: Adapt assembly for PIE support Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 02/27] x86: Use symbol name on bug table " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 03/27] x86: Use symbol name in jump " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 04/27] x86: Add macro to get symbol address " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 05/27] x86: relocate_kernel - Adapt assembly " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 06/27] x86/entry/64: " Thomas Garnier
2018-03-14 10:29 ` Peter Zijlstra
2018-03-14 15:54 ` Christopher Lameter
2018-03-14 17:09 ` Thomas Garnier
2018-03-15 10:18 ` Paolo Bonzini
2018-03-13 20:59 ` [PATCH v2 07/27] x86: pm-trace - " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 08/27] x86/CPU: " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 09/27] x86/acpi: " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 10/27] x86/boot/64: " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 11/27] x86/power/64: " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 12/27] x86/paravirt: " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 13/27] x86/boot/64: Build head64.c as mcmodel large when PIE is enabled Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 14/27] x86/percpu: Adapt percpu for PIE support Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 15/27] compiler: Option to default to hidden symbols Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 16/27] compiler: Option to add PROVIDE_HIDDEN replacement for weak symbols Thomas Garnier
2018-03-13 20:59 ` Thomas Garnier [this message]
2018-03-13 20:59 ` [PATCH v2 18/27] xen: Adapt assembly for PIE support Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 19/27] kvm: " Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 20/27] x86: Support global stack cookie Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 21/27] x86/ftrace: Adapt function tracing for PIE support Thomas Garnier
2018-03-14 10:35 ` Peter Zijlstra
2018-03-13 20:59 ` [PATCH v2 22/27] x86/modules: Add option to start module section after kernel Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 23/27] x86/modules: Adapt module loading for PIE support Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 24/27] x86/mm: Make the x86 GOT read-only Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 25/27] x86/pie: Add option to build the kernel as PIE Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 26/27] x86/relocs: Add option to generate 64-bit relocations Thomas Garnier
2018-03-13 20:59 ` [PATCH v2 27/27] x86/kaslr: Add option to extend KASLR range from 1GB to 3GB Thomas Garnier
2018-03-15 8:48 ` [PATCH v2 00/27] x86: PIE support and option to extend KASLR randomization Pavel Machek
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=20180313205945.245105-18-thgarnie@google.com \
--to=thgarnie@google.com \
--cc=acme@redhat.com \
--cc=adobriyan@gmail.com \
--cc=akataria@vmware.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=aryabinin@virtuozzo.com \
--cc=ashish@bluestacks.com \
--cc=bhe@redhat.com \
--cc=boris.ostrovsky@oracle.com \
--cc=bp@alien8.de \
--cc=bp@suse.de \
--cc=caoj.fnst@cn.fujitsu.com \
--cc=cl@linux.com \
--cc=corbet@lwn.net \
--cc=danielmicay@gmail.com \
--cc=dave.hansen@linux.intel.com \
--cc=davem@davemloft.net \
--cc=dennisszhou@gmail.com \
--cc=douly.fnst@cn.fujitsu.com \
--cc=dwmw@amazon.co.uk \
--cc=gregkh@linuxfoundation.org \
--cc=herbert@gondor.apana.org.au \
--cc=hjl.tools@gmail.com \
--cc=hpa@zytor.com \
--cc=jbaron@akamai.com \
--cc=jgross@suse.com \
--cc=joro@8bytes.org \
--cc=jpoimboe@redhat.com \
--cc=jschoenh@amazon.de \
--cc=jslaby@suse.cz \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=kstewart@linuxfoundation.org \
--cc=kvm@vger.kernel.org \
--cc=kyle@redhat.com \
--cc=len.brown@intel.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux-sparse@vger.kernel.org \
--cc=linux@dominikbrodowski.net \
--cc=lukas@wunner.de \
--cc=luto@kernel.org \
--cc=mawilcox@microsoft.com \
--cc=mcgrof@kernel.org \
--cc=me@kylehuey.com \
--cc=mhocko@suse.com \
--cc=mingo@kernel.org \
--cc=mingo@redhat.com \
--cc=mka@chromium.org \
--cc=nicolas.pitre@linaro.org \
--cc=npiggin@gmail.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=pavel@ucw.cz \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=pmladek@suse.com \
--cc=pombredanne@nexb.com \
--cc=qianyue.zj@alibaba-inc.com \
--cc=rdunlap@infradead.org \
--cc=riel@redhat.com \
--cc=rjw@rjwysocki.net \
--cc=rkrcmar@redhat.com \
--cc=rob@landley.net \
--cc=rostedt@goodmis.org \
--cc=sergey.senozhatsky.work@gmail.com \
--cc=sparse@chrisli.org \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=tj@kernel.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=x86@kernel.org \
--cc=xen-devel@lists.xenproject.org \
--cc=yamada.masahiro@socionext.com \
/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).