x86: Check static link of dynamic objects

Message ID 20200313122947.GA404470@gmail.com
State New
Headers show
Series
  • x86: Check static link of dynamic objects
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Commit Message

Jose E. Marchesi via Binutils March 13, 2020, 12:29 p.m.
On Wed, Mar 11, 2020 at 09:09:20PM -0700, Fangrui Song wrote:
> > When -static is passed to gcc, gcc passes it to linker before any input

> > files to create static executable.  If -Bdynamic is also passed to linker

> > from command-line, linker should issue an error if dynamic object is used.

> > 

> > include/

> > 

> > 	PR ld/24920

> > 	* bfdlink.h (bfd_link_info): Add static_exec.

> > 

> > ld/

> > 

> > 	PR ld/24920

> > 	* ldfile.c (ldfile_try_open_bfd): Also check link_info.static_exec

> > 	for static link of dynamic object.

> > 	* lexsup.c (parse_args): Set link_info.static_exec to true if we

> > 	see -static before any input files.

> > 	* testsuite/ld-elf/pr24920.err: New file.

> > 	* testsuite/ld-elf/shared.exp: Run ld/24920 tests.

> 

> Does the patch reject valid use case like:

> 

> ld -Bstatic a.o -Bdynamic b.so

> 


This isn't a valid use case for Linux/x86.  At minimum, -dynamic-linker
is needed for Linux/x86 to create non-static executable unless
--no-dynamic-linker is used.

> If the gcc driver detects the input file type, I think such an error should be emitted on its side.?

> 


The GCC driver passes everything at command-line to linker without any
checking.

> 

> -static = -Bstatic. There is no need to teach it to know that the first -static/-Bstatic is different.



I am testing this patch.  I will check it in there are no issues.

H.J.
---
On Linux/x86, when -static is passed to gcc, gcc passes it to linker
before all input files suitable for creating static executable.  X86
linker will report error for dynamic input objects if -static is passed
at command-line before all input files without --dynamic-linker unless
--no-dynamic-linker is used.

bfd/

	PR ld/24920
	* elf-linker-x86.h (elf_linker_x86_params): Add
	static_before_all_inputs and has_dynamic_linker.
	* elfxx-x86.c (_bfd_x86_elf_link_setup_gnu_properties): Report
	dynamic input objects if -static is passed at command-line
	before all input files without --dynamic-linker unless
	--no-dynamic-linker is used.

ld/

	PR ld/24920
	* emulparams/elf32_x86_64.sh: Use static.sh.
	* emulparams/elf_i386.sh: Likewise.
	* emulparams/elf_x86_64.sh: Likewise.
	* emulparams/static.sh: New file.
	* emultempl/elf-x86.em: Include "ldlex.h".
	* testsuite/ld-elf/pr24920.err: New file.
	* testsuite/ld-elf/linux-x86.exp: Run ld/24920 tests.
---
 bfd/elf-linker-x86.h              |  6 ++++++
 bfd/elfxx-x86.c                   | 17 ++++++++++++++++
 ld/emulparams/elf32_x86_64.sh     |  1 +
 ld/emulparams/elf_i386.sh         |  1 +
 ld/emulparams/elf_x86_64.sh       |  1 +
 ld/emulparams/static.sh           | 12 +++++++++++
 ld/emultempl/elf-x86.em           |  1 +
 ld/testsuite/ld-elf/linux-x86.exp | 33 +++++++++++++++++++++++++++----
 ld/testsuite/ld-elf/pr24920.err   |  1 +
 9 files changed, 69 insertions(+), 4 deletions(-)
 create mode 100644 ld/emulparams/static.sh
 create mode 100644 ld/testsuite/ld-elf/pr24920.err

-- 
2.24.1

Comments

Jose E. Marchesi via Binutils March 13, 2020, 11:12 p.m. | #1
On Fri, Mar 13, 2020 at 05:29:47AM -0700, H.J. Lu via Binutils wrote:
> X86

> linker will report error for dynamic input objects if -static is passed

> at command-line before all input files without --dynamic-linker


Good, you've allowed the user to specify --dynamic-linker themselves.
That was one of my concerns about making -static sticky.

-- 
Alan Modra
Australia Development Lab, IBM

Patch

diff --git a/bfd/elf-linker-x86.h b/bfd/elf-linker-x86.h
index 8ede7299dd..d0cb20dde5 100644
--- a/bfd/elf-linker-x86.h
+++ b/bfd/elf-linker-x86.h
@@ -49,6 +49,12 @@  struct elf_linker_x86_params
   /* TRUE if generate a 1-byte NOP as suffix for x86 call instruction.  */
   unsigned int call_nop_as_suffix : 1;
 
+  /* TRUE if -static is passed at command-line before all input files.  */
+  unsigned int static_before_all_inputs : 1;
+
+  /* TRUE if --dynamic-linker is passed at command-line.  */
+  unsigned int has_dynamic_linker : 1;
+
   /* Report missing IBT and SHSTK properties.  */
   enum elf_x86_cet_report cet_report;
 
diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
index 2e0e01e31d..108e04a158 100644
--- a/bfd/elfxx-x86.c
+++ b/bfd/elfxx-x86.c
@@ -2998,6 +2998,23 @@  _bfd_x86_elf_link_setup_gnu_properties
 				  : bed->plt_alignment);
     }
 
+  if (bfd_link_executable (info)
+      && !info->nointerp
+      && !htab->params->has_dynamic_linker
+      && htab->params->static_before_all_inputs)
+    {
+      /* Report error for dynamic input objects if -static is passed at
+	 command-line before all input files without --dynamic-linker
+	 unless --no-dynamic-linker is used.  */
+      bfd *abfd;
+
+      for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
+	if ((abfd->flags & DYNAMIC))
+	  info->callbacks->einfo
+	    (_("%X%P: attempted static link of dynamic object `%pB'\n"),
+	     abfd);
+    }
+
   return pbfd;
 }
 
diff --git a/ld/emulparams/elf32_x86_64.sh b/ld/emulparams/elf32_x86_64.sh
index 249553aaac..1f672c6e42 100644
--- a/ld/emulparams/elf32_x86_64.sh
+++ b/ld/emulparams/elf32_x86_64.sh
@@ -4,6 +4,7 @@  source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
 source_sh ${srcdir}/emulparams/reloc_overflow.sh
 source_sh ${srcdir}/emulparams/call_nop.sh
 source_sh ${srcdir}/emulparams/cet.sh
+source_sh ${srcdir}/emulparams/static.sh
 SCRIPT_NAME=elf
 ELFSIZE=32
 OUTPUT_FORMAT="elf32-x86-64"
diff --git a/ld/emulparams/elf_i386.sh b/ld/emulparams/elf_i386.sh
index 645707ddbd..c98d5e6600 100644
--- a/ld/emulparams/elf_i386.sh
+++ b/ld/emulparams/elf_i386.sh
@@ -3,6 +3,7 @@  source_sh ${srcdir}/emulparams/extern_protected_data.sh
 source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
 source_sh ${srcdir}/emulparams/call_nop.sh
 source_sh ${srcdir}/emulparams/cet.sh
+source_sh ${srcdir}/emulparams/static.sh
 SCRIPT_NAME=elf
 OUTPUT_FORMAT="elf32-i386"
 NO_RELA_RELOCS=yes
diff --git a/ld/emulparams/elf_x86_64.sh b/ld/emulparams/elf_x86_64.sh
index 2b34941986..be98082982 100644
--- a/ld/emulparams/elf_x86_64.sh
+++ b/ld/emulparams/elf_x86_64.sh
@@ -4,6 +4,7 @@  source_sh ${srcdir}/emulparams/dynamic_undefined_weak.sh
 source_sh ${srcdir}/emulparams/reloc_overflow.sh
 source_sh ${srcdir}/emulparams/call_nop.sh
 source_sh ${srcdir}/emulparams/cet.sh
+source_sh ${srcdir}/emulparams/static.sh
 SCRIPT_NAME=elf
 ELFSIZE=64
 OUTPUT_FORMAT="elf64-x86-64"
diff --git a/ld/emulparams/static.sh b/ld/emulparams/static.sh
new file mode 100644
index 0000000000..410839b8a5
--- /dev/null
+++ b/ld/emulparams/static.sh
@@ -0,0 +1,12 @@ 
+PARSE_AND_LIST_ARGS_CASES="$PARSE_AND_LIST_ARGS_CASES
+    case OPTION_DYNAMIC_LINKER:
+      params.has_dynamic_linker = TRUE;
+      return FALSE;
+
+    case OPTION_NON_SHARED:
+      /* Check if -static is passed at command-line before all input
+	 files.  */
+      if (!lang_has_input_file)
+	params.static_before_all_inputs = TRUE;
+      return FALSE;
+"
diff --git a/ld/emultempl/elf-x86.em b/ld/emultempl/elf-x86.em
index 8de4491699..e18caffbb2 100644
--- a/ld/emultempl/elf-x86.em
+++ b/ld/emultempl/elf-x86.em
@@ -22,6 +22,7 @@ 
 #
 fragment <<EOF
 
+#include "ldlex.h"
 #include "elf-linker-x86.h"
 
 static struct elf_linker_x86_params params;
diff --git a/ld/testsuite/ld-elf/linux-x86.exp b/ld/testsuite/ld-elf/linux-x86.exp
index d304fb1442..63a321b966 100644
--- a/ld/testsuite/ld-elf/linux-x86.exp
+++ b/ld/testsuite/ld-elf/linux-x86.exp
@@ -19,11 +19,36 @@ 
 # MA 02110-1301, USA.
 #
 
+# Linux/x86 tests.
+if { ![istarget "i?86-*-linux*"] \
+       && ![istarget "x86_64-*-linux*"] \
+       && ![istarget "amd64-*-linux*"] } {
+    return
+}
+
+run_ld_link_tests [list \
+    [list \
+	"Build pr24920.so" \
+	"-shared" \
+	"" \
+	"" \
+	{dummy.s} \
+	{} \
+	"pr24920.so" \
+    ] \
+    [list \
+	"Build pr24920" \
+	"-static " \
+	"-Bdynamic tmpdir/pr24920.so" \
+	"" \
+	{start.s} \
+	{{ld pr24920.err}} \
+	"pr24920" \
+    ] \
+]
+
 # Test very simple native Linux/x86 programs with linux-x86.S.
-if { ![isnative] || ![check_compiler_available] \
-     || (![istarget "i?86-*-linux*"] \
-         && ![istarget "x86_64-*-linux*"] \
-         && ![istarget "amd64-*-linux*"]) } {
+if { ![isnative] || ![check_compiler_available] } {
     return
 }
 
diff --git a/ld/testsuite/ld-elf/pr24920.err b/ld/testsuite/ld-elf/pr24920.err
new file mode 100644
index 0000000000..8f5cab9167
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr24920.err
@@ -0,0 +1 @@ 
+.*: attempted static link of dynamic object `tmpdir/pr24920.so'