From: Mark Wielaard <mjw@redhat.com>
Date: Thu, 4 Jun 2015 14:25:37 +0000 (+0200)
Subject: libelf: Make sure elf_getdata_rawchunk returns aligned data.
X-Git-Tag: elfutils-0.162~8
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ede1d9d8aa4b04810e1ee04fcec9386e63f48d77;p=thirdparty%2Felfutils.git

libelf: Make sure elf_getdata_rawchunk returns aligned data.

elf_getdata_rawchunk might return an unaligned buffer for the requested
ELF data type. Make sure the data is also correctly aligned when using
an mmapped file. Also add some missing alignments for ELF data types
for __libelf_type_align (the missing types could also make elf_getdata
to return unaligned data).

Signed-off-by: Mark Wielaard <mjw@redhat.com>
---

diff --git a/libelf/ChangeLog b/libelf/ChangeLog
index 25f673db3..30017cd7a 100644
--- a/libelf/ChangeLog
+++ b/libelf/ChangeLog
@@ -1,3 +1,11 @@
+2015-06-04  Mark Wielaard  <mjw@redhat.com>
+
+	* elf_getdata.c (__libelf_type_aligns): Add entries for ELF_T_EHDR,
+	ELF_T_OFF, ELF_T_PHDR, ELF_T_SHDR, ELF_T_SWORD, ELF_T_XWORD,
+	ELF_T_SXWORD, ELF_T_GNUHASH, ELF_T_AUXV.
+	* elf_getdata_rawchunk.c (elf_getdata_rawchunk): Check alignment
+	of rawdata against requested type.
+
 2015-06-02  Mark Wielaard  <mjw@redhat.com>
 
 	* elf_getdata.c (convert_data): Make sure source data is properly
diff --git a/libelf/elf_getdata.c b/libelf/elf_getdata.c
index 1a4981efb..770e03550 100644
--- a/libelf/elf_getdata.c
+++ b/libelf/elf_getdata.c
@@ -83,8 +83,15 @@ const uint_fast8_t __libelf_type_aligns[EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM]
 # define TYPE_ALIGNS(Bits)						      \
     {									      \
       [ELF_T_ADDR] = __alignof__ (ElfW2(Bits,Addr)),			      \
+      [ELF_T_EHDR] = __alignof__ (ElfW2(Bits,Ehdr)),			      \
       [ELF_T_HALF] = __alignof__ (ElfW2(Bits,Half)),			      \
+      [ELF_T_OFF] = __alignof__ (ElfW2(Bits,Off)),			      \
+      [ELF_T_PHDR] = __alignof__ (ElfW2(Bits,Phdr)),			      \
+      [ELF_T_SHDR] = __alignof__ (ElfW2(Bits,Shdr)),			      \
+      [ELF_T_SWORD] = __alignof__ (ElfW2(Bits,Sword)),			      \
       [ELF_T_WORD] = __alignof__ (ElfW2(Bits,Word)),			      \
+      [ELF_T_XWORD] = __alignof__ (ElfW2(Bits,Xword)),			      \
+      [ELF_T_SXWORD] = __alignof__ (ElfW2(Bits,Sxword)),		      \
       [ELF_T_SYM] = __alignof__ (ElfW2(Bits,Sym)),			      \
       [ELF_T_SYMINFO] = __alignof__ (ElfW2(Bits,Syminfo)),		      \
       [ELF_T_REL] = __alignof__ (ElfW2(Bits,Rel)),			      \
@@ -97,6 +104,8 @@ const uint_fast8_t __libelf_type_aligns[EV_NUM - 1][ELFCLASSNUM - 1][ELF_T_NUM]
       [ELF_T_MOVE] = __alignof__ (ElfW2(Bits,Move)),			      \
       [ELF_T_LIB] = __alignof__ (ElfW2(Bits,Lib)),			      \
       [ELF_T_NHDR] = __alignof__ (ElfW2(Bits,Nhdr)),			      \
+      [ELF_T_GNUHASH] = __alignof__ (Elf32_Word),			      \
+      [ELF_T_AUXV] = __alignof__ (ElfW2(Bits,auxv_t)),			      \
     }
     [EV_CURRENT - 1] =
     {
diff --git a/libelf/elf_getdata_rawchunk.c b/libelf/elf_getdata_rawchunk.c
index 63a9914fd..5cc11e702 100644
--- a/libelf/elf_getdata_rawchunk.c
+++ b/libelf/elf_getdata_rawchunk.c
@@ -79,9 +79,24 @@ elf_getdata_rawchunk (elf, offset, size, type)
 
   rwlock_rdlock (elf->lock);
 
-  /* If the file is mmap'ed we can use it directly.  */
+  size_t align = __libelf_type_align (elf->class, type);
   if (elf->map_address != NULL)
-    rawchunk = elf->map_address + elf->start_offset + offset;
+    {
+    /* If the file is mmap'ed we can use it directly, if aligned for type.  */
+      char *rawdata = elf->map_address + elf->start_offset + offset;
+      if (ALLOW_UNALIGNED ||
+	  ((uintptr_t) rawdata & (align - 1)) == 0)
+	rawchunk = rawdata;
+      else
+	{
+	  /* We allocate the memory and memcpy it to get aligned data. */
+	  rawchunk = malloc (size);
+	  if (rawchunk == NULL)
+	    goto nomem;
+	  memcpy (rawchunk, rawdata, size);
+	  flags = ELF_F_MALLOCED;
+	}
+    }
   else
     {
       /* We allocate the memory and read the data from the file.  */
@@ -108,7 +123,6 @@ elf_getdata_rawchunk (elf, offset, size, type)
     }
 
   /* Copy and/or convert the data as needed for aligned native-order access.  */
-  size_t align = __libelf_type_align (elf->class, type);
   void *buffer;
   if (elf->state.elf32.ehdr->e_ident[EI_DATA] == MY_ELFDATA)
     {