[PATCH] libelf: Fix elf_newdata when raw data has been read, but not converted.

[Mark Wielaard <mjw at redhat dot com>]

When ELF data for a section has been read by elf_rawdata, data_read
and rawdata_base are set, but data_list_rear will not be set until the
data will be converted (by elf_getdata). elf_newdata would overwrite
the existing data in that case.

Add newdata test that calls elf_newdata before and after elf_rawdata
and elf_getdata and checks the new size of the section.

Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
 libelf/ChangeLog     |   4 +
 libelf/elf_newdata.c |  13 +-
 tests/ChangeLog      |   7 +
 tests/Makefile.am    |   5 +-
 tests/newdata.c      | 365 +++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 390 insertions(+), 4 deletions(-)
 create mode 100644 tests/newdata.c

diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index 6699052..36a6031 100644
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,5 +1,9 @@
 2015-01-20  Mark Wielaard  <mjw@redhat.com>
 
+	* elf_newdata.c (elf_newdata): Check scn->rawdata_base.
+
+2015-01-20  Mark Wielaard  <mjw@redhat.com>
+
 	* elf_strptr.c (elf_strptr): Call __elf[32|64]_getshdr_rdlock if
 	necessary.
 
diff --git a/libelf/elf_newdata.c b/libelf/elf_newdata.c
index 90d1813..06baeb5 100644
--- a/libelf/elf_newdata.c
+++ b/libelf/elf_newdata.c
@@ -1,5 +1,5 @@
 /* Create new, empty section data.
-   Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
+   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2015 Red Hat, Inc.
    This file is part of elfutils.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1998.
 
@@ -64,7 +64,16 @@ elf_newdata (Elf_Scn *scn)
 
   rwlock_wrlock (scn->elf->lock);
 
-  if (scn->data_read && scn->data_list_rear == NULL)
+  /* data_read is set when data has been read from the ELF image or
+     when a new section has been created by elf_newscn.  If data has
+     been read from the ELF image, then rawdata_base will point to raw
+     data.  If data_read has been set by elf_newscn, then rawdata_base
+     will be NULL.  data_list_rear will be set by elf_getdata if the
+     data has been converted, or by this function, elf_newdata, when
+     new data has been added.  */
+  if (scn->data_read
+      && scn->rawdata_base == NULL
+      && scn->data_list_rear == NULL)
     {
       /* This means the section was created by the user and this is the
 	 first data.  */
diff --git a/tests/ChangeLog b/tests/ChangeLog
index f94d9be..d41d0e1 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,5 +1,12 @@
 2015-01-20  Mark Wielaard  <mjw@redhat.com>
 
+	* Makefile.am (check_PROGRAMS): Add newdata.
+	(TESTS): Likewise.
+	(newdata_LDADD): new variable.
+	* newdata.c: New test.
+
+2015-01-20  Mark Wielaard  <mjw@redhat.com>
+
 	* strptr.c: New file.
 	* run-strptr.sh: New test.
 	* Makefile.am (check_PROGRAMS): Add strptr.
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c3364a2..4420e8b 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -51,7 +51,7 @@ check_PROGRAMS = arextract arsymtest newfile saridx scnnames sectiondump \
 		  dwfl-report-elf-align varlocs backtrace backtrace-child \
 		  backtrace-data backtrace-dwarf debuglink debugaltlink \
 		  buildid deleted deleted-lib.so aggregate_size vdsosyms \
-		  getsrc_die strptr
+		  getsrc_die strptr newdata
 
 asm_TESTS = asm-tst1 asm-tst2 asm-tst3 asm-tst4 asm-tst5 \
 	    asm-tst6 asm-tst7 asm-tst8 asm-tst9
@@ -113,7 +113,7 @@ TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \
 	run-backtrace-demangle.sh run-stack-d-test.sh run-stack-i-test.sh \
 	run-readelf-dwz-multi.sh run-allfcts-multi.sh run-deleted.sh \
 	run-linkmap-cut.sh run-aggregate-size.sh vdsosyms run-readelf-A.sh \
-	run-getsrc-die.sh run-strptr.sh
+	run-getsrc-die.sh run-strptr.sh newdata
 
 if !BIARCH
 export ELFUTILS_DISABLE_BIARCH = 1
@@ -426,6 +426,7 @@ aggregate_size_LDADD = $(libdw) $(libelf)
 vdsosyms_LDADD = $(libdw) $(libelf)
 getsrc_die_LDADD = $(libdw) $(libelf)
 strptr_LDADD = $(libelf)
+newdata_LDADD = $(libelf)
 
 if GCOV
 check: check-am coverage
diff --git a/tests/newdata.c b/tests/newdata.c
new file mode 100644
index 0000000..7dfe962
--- /dev/null
+++ b/tests/newdata.c
@@ -0,0 +1,365 @@
+/* Test program for elf_newdata function.
+   Copyright (C) 2015 Red Hat, Inc.
+   This file is part of elfutils.
+
+   This file is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   elfutils is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include ELFUTILS_HEADER(elf)
+#include <gelf.h>
+
+// Random data string (16 bytes).
+static char *DATA = "123456789ABCDEF";
+static size_t DATA_LEN = 16;
+
+static void
+add_section_data (Elf *elf, char *buf, size_t len)
+{
+  printf ("Adding %zd bytes.\n", len);
+
+  Elf_Scn *scn = elf_getscn (elf, 1);
+  if (scn == NULL)
+    {
+      printf ("couldn't get data section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  Elf_Data *data = elf_newdata (scn);
+  if (data == NULL)
+    {
+      printf ("cannot create newdata for section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  data->d_buf = buf;
+  data->d_type = ELF_T_BYTE;
+  data->d_size = len;
+  data->d_align = 1;
+  data->d_version = EV_CURRENT;
+
+  // Let the library compute the internal structure information.
+  if (elf_update (elf, ELF_C_NULL) < 0)
+    {
+      printf ("failure in elf_update(NULL): %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+}
+
+static Elf *
+create_elf (int fd, int class)
+{
+  Elf *elf = elf_begin (fd, ELF_C_WRITE, NULL);
+  if (elf == NULL)
+    {
+      printf ("cannot create ELF descriptor: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  // Create an ELF header.
+  if (gelf_newehdr (elf, class) == 0)
+    {
+      printf ("cannot create ELF header: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  GElf_Ehdr ehdr_mem;
+  GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
+  if (ehdr == NULL)
+    {
+      printf ("cannot get ELF header: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  // Initialize header.
+  ehdr->e_ident[EI_DATA] = ELFCLASS32 ? ELFDATA2LSB : ELFDATA2MSB;
+  ehdr->e_ident[EI_OSABI] = ELFOSABI_GNU;
+  ehdr->e_type = ET_NONE;
+  ehdr->e_machine = class == ELFCLASS32 ? EM_PPC : EM_X86_64;
+  ehdr->e_version = EV_CURRENT;
+
+  // Update the ELF header.
+  if (gelf_update_ehdr (elf, ehdr) == 0)
+    {
+      printf ("cannot update ELF header: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  // Create a section.
+  Elf_Scn *scn = elf_newscn (elf);
+  if (scn == NULL)
+    {
+      printf ("cannot create new section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  GElf_Shdr shdr_mem;
+  GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
+  if (shdr == NULL)
+    {
+      printf ("cannot get header for data section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  shdr->sh_type = SHT_PROGBITS;
+  shdr->sh_flags = 0;
+  shdr->sh_addr = 0;
+  shdr->sh_link = SHN_UNDEF;
+  shdr->sh_info = SHN_UNDEF;
+  shdr->sh_addralign = 1;
+  shdr->sh_entsize = 1;
+  shdr->sh_name = 0;
+
+  // Finish section, update the header.
+  if (gelf_update_shdr (scn, shdr) == 0)
+    {
+      printf ("cannot update header for DATA section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  // Add some data to the section.
+  add_section_data (elf, DATA, DATA_LEN);
+
+  // Write everything to disk.
+  if (elf_update (elf, ELF_C_WRITE) < 0)
+    {
+      printf ("failure in elf_update(WRITE): %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  return elf;
+}
+
+static Elf *
+read_elf (int fd)
+{
+  printf ("Reading ELF file\n");
+  Elf *elf = elf_begin (fd, ELF_C_RDWR, NULL);
+  if (elf == NULL)
+    {
+      printf ("cannot create ELF descriptor read-again: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  return elf;
+}
+
+static void
+check_section_size (Elf *elf, size_t size)
+{
+  Elf_Scn *scn = elf_getscn (elf, 1);
+  if (scn == NULL)
+    {
+      printf ("couldn't get data section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  GElf_Shdr shdr_mem;
+  GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
+  if (shdr == NULL)
+    {
+      printf ("cannot get header for DATA section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  if (shdr->sh_size == size)
+    printf ("OK %zd bytes.\n", size);
+  else
+    {
+      printf ("BAD size, expected %zd, got %" PRIu64 "\n",
+	      size, shdr->sh_size);
+      exit (-1);
+    }
+}
+
+static void
+check_elf (int class)
+{
+  static const char *fname;
+  fname = class == ELFCLASS32 ? "newdata.elf32" : "newdata.elf64";
+
+  printf ("check_elf: %s\n", fname);
+
+  int fd = open (fname, O_RDWR|O_CREAT|O_TRUNC, 00666);
+  if (fd == -1)
+    {
+      printf ("cannot create `%s': %s\n", fname, strerror (errno));
+      exit (1);
+    }
+
+  Elf *elf = create_elf (fd, class);
+  check_section_size (elf, DATA_LEN);
+
+  // Add some more data (won't be written to disk).
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 2 * DATA_LEN);
+
+  if (elf_end (elf) != 0)
+    {
+      printf ("failure in elf_end: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  close (fd);
+
+  // Read the ELF from disk now.  And add new data directly.
+  fd = open (fname, O_RDONLY);
+  if (fd == -1)
+    {
+      printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
+      exit (1);
+    }
+
+  elf = read_elf (fd);
+  check_section_size (elf, DATA_LEN);
+
+  // Add some more data.
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 2 * DATA_LEN);
+
+  // And some more.
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 3 * DATA_LEN);
+
+  if (elf_end (elf) != 0)
+    {
+      printf ("failure in elf_end: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  close (fd);
+
+  // Read the ELF from disk now.  And add new data after raw reading.
+  fd = open (fname, O_RDONLY);
+  if (fd == -1)
+    {
+      printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
+      exit (1);
+    }
+
+  elf = read_elf (fd);
+  check_section_size (elf, DATA_LEN);
+
+  // Get raw data before adding new data.
+  Elf_Scn *scn = elf_getscn (elf, 1);
+  if (scn == NULL)
+    {
+      printf ("couldn't get data section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  printf ("elf_rawdata\n");
+  Elf_Data *data = elf_rawdata (scn, NULL);
+  if (data == NULL)
+    {
+      printf ("couldn't get raw data from section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  if (data->d_size != DATA_LEN)
+    {
+      printf ("Unexpected Elf_Data: %zd", data->d_size);
+      exit (1);
+    }
+
+  // Now add more data.
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 2 * DATA_LEN);
+
+  // And some more.
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 3 * DATA_LEN);
+
+  if (elf_end (elf) != 0)
+    {
+      printf ("failure in elf_end: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  close (fd);
+
+  // Read the ELF from disk now.  And add new data after data reading.
+  fd = open (fname, O_RDONLY);
+  if (fd == -1)
+    {
+      printf ("cannot open `%s' read-only: %s\n", fname, strerror (errno));
+      exit (1);
+    }
+
+  elf = read_elf (fd);
+  check_section_size (elf, DATA_LEN);
+
+  // Get raw data before adding new data.
+  scn = elf_getscn (elf, 1);
+  if (scn == NULL)
+    {
+      printf ("couldn't get data section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  printf ("elf_getdata\n");
+  data = elf_getdata (scn, NULL);
+  if (data == NULL)
+    {
+      printf ("couldn't get raw data from section: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  if (data->d_size != DATA_LEN)
+    {
+      printf ("Unexpected Elf_Data: %zd", data->d_size);
+      exit (1);
+    }
+
+  // Now add more data.
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 2 * DATA_LEN);
+
+  // And some more.
+  add_section_data (elf, DATA, DATA_LEN);
+  check_section_size (elf, 3 * DATA_LEN);
+
+  if (elf_end (elf) != 0)
+    {
+      printf ("failure in elf_end: %s\n", elf_errmsg (-1));
+      exit (1);
+    }
+
+  close (fd);
+
+  unlink (fname);
+}
+
+int
+main (int argc __attribute__ ((unused)), char *argv[] __attribute__ ((unused)))
+{
+  // Initialize libelf.
+  elf_version (EV_CURRENT);
+
+  check_elf (ELFCLASS32);
+  check_elf (ELFCLASS64);
+
+  return 0;
+}
-- 
1.8.3.1