ldconfig-native: Fix to point correctly on the DT_NEEDED entries in an ELF file

When ldconfig-native reads an ELF file, it computes an offset from a LOAD
segment, to point on DT NEEDED entries of dynstr section.
Without this patch, ldconfig-native uses only the first LOAD segment, even if
the offset is incorrect.
This patch adds conditions to compute the offset by parsing all LOAD segments,
one by one.

This is a backport from [0], ported to support endianness and 32/64 bits.

[0]: https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=58e8f5fd2ba47b6dc47fd4d0a35e4175c7c87aaa

(From OE-Core rev: 602ccc57360f85e55b1455b93ba9b7e7bf23799e)

Signed-off-by: Fabien Mahot <fabien.mahot@external.desouttertools.com>
Reviewed-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 179 insertions, 0 deletions

diff --git a/meta/recipes-core/glibc/ldconfig-native-2.12.1/ldconfig-handle-.dynstr-located-in-separate-segment.patch b/meta/recipes-core/glibc/ldconfig-native-2.12.1/ldconfig-handle-.dynstr-located-in-separate-segment.patch
new file mode 100644
index 0000000000..36f04adfde
--- /dev/null
+++ b/meta/recipes-core/glibc/ldconfig-native-2.12.1/ldconfig-handle-.dynstr-located-in-separate-segment.patch
@@ -0,0 +1,178 @@
+From 864054a6cb971688a181316b8227ae0361b4d69e Mon Sep 17 00:00:00 2001
+From: Andreas Schwab <schwab@suse.de>
+Date: Wed, 9 Oct 2019 17:46:47 +0200
+Subject: [PATCH] ldconfig: handle .dynstr located in separate segment (bug
+ 25087)
+
+To determine the load offset of the DT_STRTAB section search for the
+segment containing it, instead of using the load offset of the first
+segment.
+
+Upstream-Status: Backport [https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=58e8f5fd2ba47b6dc47fd4d0a35e4175c7c87aaa]
+
+Backported: ported to support endianness and 32/64 bits.
+Signed-off-by: Fabien Mahot <fabien.mahot@external.desouttertools.com>
+---
+ readelflib.c | 86 +++++++++++++++++++++++++++++++---------------------
+ 1 file changed, 52 insertions(+), 34 deletions(-)
+
+diff --git a/readelflib.c b/readelflib.c
+index a01e1cede3..380aed563d 100644
+--- a/readelflib.c
++++ b/readelflib.c
+@@ -80,7 +80,6 @@ process_elf_file32 (const char *file_name, const char *lib, int *flag,
+ {
+   int i;
+   unsigned int j;
+-  Elf32_Addr loadaddr;
+   unsigned int dynamic_addr;
+   size_t dynamic_size;
+   char *program_interpreter;
+@@ -110,7 +109,6 @@ process_elf_file32 (const char *file_name, const char *lib, int *flag,
+      libc5/libc6.  */
+   *flag = FLAG_ELF;
+ 
+-  loadaddr = -1;
+   dynamic_addr = 0;
+   dynamic_size = 0;
+   program_interpreter = NULL;
+@@ -121,11 +119,6 @@ process_elf_file32 (const char *file_name, const char *lib, int *flag,
+ 
+       switch (read32(segment->p_type, be))
+        {
+-       case PT_LOAD:
+-         if (loadaddr == (Elf32_Addr) -1)
+-           loadaddr = read32(segment->p_vaddr, be) - read32(segment->p_offset, be);
+-         break;
+-
+        case PT_DYNAMIC:
+          if (dynamic_addr)
+            error (0, 0, _("more than one dynamic segment\n"));
+@@ -188,11 +181,6 @@ process_elf_file32 (const char *file_name, const char *lib, int *flag,
+        }
+ 
+     }
+-  if (loadaddr == (Elf32_Addr) -1)
+-    {
+-      /* Very strange. */
+-      loadaddr = 0;
+-    }
+ 
+   /* Now we can read the dynamic sections.  */
+   if (dynamic_size == 0)
+@@ -208,11 +196,32 @@ process_elf_file32 (const char *file_name, const char *lib, int *flag,
+     {
+       check_ptr (dyn_entry);
+       if (read32(dyn_entry->d_tag, be) == DT_STRTAB)
+-       {
+-         dynamic_strings = (char *) (file_contents + read32(dyn_entry->d_un.d_val, be) - loadaddr);
+-         check_ptr (dynamic_strings);
+-         break;
+-       }
++        {
++          /* Find the file offset of the segment containing the dynamic
++             string table.  */
++          Elf32_Off loadoff = -1;
++          for (i = 0, segment = elf_pheader;
++               i < read16(elf_header->e_phnum, be); i++, segment++)
++            {
++              if (read32(segment->p_type, be) == PT_LOAD
++                  && read32(dyn_entry->d_un.d_val, be) >= read32(segment->p_vaddr, be)
++                  && (read32(dyn_entry->d_un.d_val, be) - read32(segment->p_vaddr, be)
++                      < read32(segment->p_filesz, be)))
++                {
++                  loadoff = read32(segment->p_vaddr, be) - read32(segment->p_offset, be);
++                  break;
++                }
++            }
++          if (loadoff == (Elf32_Off) -1)
++            {
++              /* Very strange. */
++              loadoff = 0;
++            }
++
++          dynamic_strings = (char *) (file_contents + read32(dyn_entry->d_un.d_val, be) - loadoff);
++          check_ptr (dynamic_strings);
++          break;
++        }
+     }
+ 
+   if (dynamic_strings == NULL)
+@@ -269,7 +278,6 @@ process_elf_file64 (const char *file_name, const char *lib, int *flag,
+ {
+   int i;
+   unsigned int j;
+-  Elf64_Addr loadaddr;
+   Elf64_Addr dynamic_addr;
+   Elf64_Xword dynamic_size;
+   char *program_interpreter;
+@@ -347,7 +355,6 @@ process_elf_file64 (const char *file_name, const char *lib, int *flag,
+       break;
+     }
+ 
+-  loadaddr = -1;
+   dynamic_addr = 0;
+   dynamic_size = 0;
+   program_interpreter = NULL;
+@@ -358,11 +365,6 @@ process_elf_file64 (const char *file_name, const char *lib, int *flag,
+ 
+       switch (read32(segment->p_type, be))
+        {
+-       case PT_LOAD:
+-         if (loadaddr == (Elf64_Addr) -1)
+-           loadaddr = read64(segment->p_vaddr, be) - read64(segment->p_offset, be);
+-         break;
+-
+        case PT_DYNAMIC:
+          if (dynamic_addr)
+            error (0, 0, _("more than one dynamic segment\n"));
+@@ -426,11 +428,6 @@ process_elf_file64 (const char *file_name, const char *lib, int *flag,
+        }
+ 
+     }
+-  if (loadaddr == (Elf64_Addr) -1)
+-    {
+-      /* Very strange. */
+-      loadaddr = 0;
+-    }
+ 
+   /* Now we can read the dynamic sections.  */
+   if (dynamic_size == 0)
+@@ -446,11 +443,32 @@ process_elf_file64 (const char *file_name, const char *lib, int *flag,
+     {
+       check_ptr (dyn_entry);
+       if (read64(dyn_entry->d_tag, be) == DT_STRTAB)
+-       {
+-         dynamic_strings = (char *) (file_contents + read64(dyn_entry->d_un.d_val, be) - loadaddr);
+-         check_ptr (dynamic_strings);
+-         break;
+-       }
++        {
++          /* Find the file offset of the segment containing the dynamic
++             string table.  */
++          Elf64_Off loadoff = -1;
++          for (i = 0, segment = elf_pheader;
++               i < read16(elf_header->e_phnum, be); i++, segment++)
++            {
++              if (read64(segment->p_type, be) == PT_LOAD
++                  && read64(dyn_entry->d_un.d_val, be) >= read64(segment->p_vaddr, be)
++                  && (read64(dyn_entry->d_un.d_val, be) - read64(segment->p_vaddr, be)
++                      < read64(segment->p_filesz, be)))
++                {
++                  loadoff = read64(segment->p_vaddr, be) - read64(segment->p_offset, be);
++                  break;
++                }
++            }
++          if (loadoff == (Elf32_Off) -1)
++            {
++              /* Very strange. */
++              loadoff = 0;
++            }
++
++          dynamic_strings = (char *) (file_contents + read64(dyn_entry->d_un.d_val, be) - loadoff);
++          check_ptr (dynamic_strings);
++          break;
++        }
+     }
+ 
+   if (dynamic_strings == NULL)
diff --git a/meta/recipes-core/glibc/ldconfig-native_2.12.1.bb b/meta/recipes-core/glibc/ldconfig-native_2.12.1.bb
index e867ceb3ec..665a3d324c 100644
--- a/meta/recipes-core/glibc/ldconfig-native_2.12.1.bb
+++ b/meta/recipes-core/glibc/ldconfig-native_2.12.1.bb
@@ -16,6 +16,7 @@ SRC_URI = "file://ldconfig-native-2.12.1.tar.bz2 \
            file://add-64-bit-flag-for-ELF64-entries.patch \
            file://no-aux-cache.patch \
            file://add-riscv-support.patch \
+           file://ldconfig-handle-.dynstr-located-in-separate-segment.patch \
 "
 
 PR = "r2"