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[binutils-gdb/binutils-2_29-branch] x86: Check for valid PLT section size


https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=bb0216e26681531bf967a6a3f1800789ade3693d

commit bb0216e26681531bf967a6a3f1800789ade3693d
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Aug 28 11:25:58 2017 -0700

    x86: Check for valid PLT section size
    
    Update x86 get_synthetic_symtab to check for valid PLT section size
    before examining PLT section contents.
    
    	PR binutils/22018
    	* elf32-i386.c (elf_i386_get_synthetic_symtab): Check for valid
    	PLT section size.
    	* elf64-x86-64.c (elf_x86_64_get_synthetic_symtab): Likewise.
    
    (cherry picked from commit 90efb6422939ca031804266fba669f77c22a274a)

Diff:
---
 bfd/ChangeLog      |  7 +++++++
 bfd/elf32-i386.c   | 19 +++++++++++++------
 bfd/elf64-x86-64.c | 14 +++++++++++---
 3 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index fc93dec..a78e819 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2017-09-09  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR binutils/22018
+	* elf32-i386.c (elf_i386_get_synthetic_symtab): Check for valid
+	PLT section size.
+	* elf64-x86-64.c (elf_x86_64_get_synthetic_symtab): Likewise.
+
 2017-09-05  Nick Clifton  <nickc@redhat.com>
 
 	Import from mainline:
diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index c123f12..00a6397 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -6372,7 +6372,7 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
   for (j = 0; plts[j].name != NULL; j++)
     {
       plt = bfd_get_section_by_name (abfd, plts[j].name);
-      if (plt == NULL)
+      if (plt == NULL || plt->size == 0)
 	continue;
 
       /* Get the PLT section contents.  */
@@ -6388,7 +6388,9 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 
       /* Check what kind of PLT it is.  */
       plt_type = plt_unknown;
-      if (plts[j].type == plt_unknown)
+      if (plts[j].type == plt_unknown
+	  && (plt->size >= (lazy_plt->plt0_entry_size
+			    + lazy_plt->plt_entry_size)))
 	{
 	  /* Match lazy PLT first.  */
 	  if (memcmp (plt_contents, lazy_plt->plt0_entry,
@@ -6397,7 +6399,7 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	      /* The fist entry in the lazy IBT PLT is the same as the
 		 normal lazy PLT.  */
 	      if (lazy_ibt_plt != NULL
-		  && (memcmp (plt_contents + lazy_ibt_plt->plt_entry_size,
+		  && (memcmp (plt_contents + lazy_ibt_plt->plt0_entry_size,
 			      lazy_ibt_plt->plt_entry,
 			      lazy_ibt_plt->plt_got_offset) == 0))
 		plt_type = plt_lazy | plt_second;
@@ -6410,7 +6412,7 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	      /* The fist entry in the PIC lazy IBT PLT is the same as
 		 the normal PIC lazy PLT.  */
 	      if (lazy_ibt_plt != NULL
-		  && (memcmp (plt_contents + lazy_ibt_plt->plt_entry_size,
+		  && (memcmp (plt_contents + lazy_ibt_plt->plt0_entry_size,
 			      lazy_ibt_plt->pic_plt_entry,
 			      lazy_ibt_plt->plt_got_offset) == 0))
 		plt_type = plt_lazy | plt_pic | plt_second;
@@ -6420,7 +6422,8 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	}
 
       if (non_lazy_plt != NULL
-	  && (plt_type == plt_unknown || plt_type == plt_non_lazy))
+	  && (plt_type == plt_unknown || plt_type == plt_non_lazy)
+	  && plt->size >= non_lazy_plt->plt_entry_size)
 	{
 	  /* Match non-lazy PLT.  */
 	  if (memcmp (plt_contents, non_lazy_plt->plt_entry,
@@ -6432,7 +6435,8 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	}
 
       if ((non_lazy_ibt_plt != NULL)
-	  && (plt_type == plt_unknown || plt_type == plt_second))
+	  && (plt_type == plt_unknown || plt_type == plt_second)
+	  && plt->size >= non_lazy_ibt_plt->plt_entry_size)
 	{
 	  if (memcmp (plt_contents,
 		      non_lazy_ibt_plt->plt_entry,
@@ -6490,6 +6494,9 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	got_addr = (bfd_vma) -1;
     }
 
+  if (count == 0)
+    return -1;
+
   size = count * sizeof (asymbol);
   s = *ret = (asymbol *) bfd_zmalloc (size);
   if (s == NULL)
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index c59b8c0..6bc1898 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -6752,7 +6752,7 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
   for (j = 0; plts[j].name != NULL; j++)
     {
       plt = bfd_get_section_by_name (abfd, plts[j].name);
-      if (plt == NULL)
+      if (plt == NULL || plt->size == 0)
 	continue;
 
       /* Get the PLT section contents.  */
@@ -6768,7 +6768,9 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
 
       /* Check what kind of PLT it is.  */
       plt_type = plt_unknown;
-      if (plts[j].type == plt_unknown)
+      if (plts[j].type == plt_unknown
+	  && (plt->size >= (lazy_plt->plt_entry_size
+			    + lazy_plt->plt_entry_size)))
 	{
 	  /* Match lazy PLT first.  Need to check the first two
 	     instructions.   */
@@ -6796,7 +6798,8 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
 	}
 
       if (non_lazy_plt != NULL
-	  && (plt_type == plt_unknown || plt_type == plt_non_lazy))
+	  && (plt_type == plt_unknown || plt_type == plt_non_lazy)
+	  && plt->size >= non_lazy_plt->plt_entry_size)
 	{
 	  /* Match non-lazy PLT.  */
 	  if (memcmp (plt_contents, non_lazy_plt->plt_entry,
@@ -6807,6 +6810,7 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
       if (plt_type == plt_unknown || plt_type == plt_second)
 	{
 	  if (non_lazy_bnd_plt != NULL
+	      && plt->size >= non_lazy_bnd_plt->plt_entry_size
 	      && (memcmp (plt_contents, non_lazy_bnd_plt->plt_entry,
 			  non_lazy_bnd_plt->plt_got_offset) == 0))
 	    {
@@ -6815,6 +6819,7 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
 	      non_lazy_plt = non_lazy_bnd_plt;
 	    }
 	  else if (non_lazy_ibt_plt != NULL
+		   && plt->size >= non_lazy_ibt_plt->plt_entry_size
 		   && (memcmp (plt_contents,
 			       non_lazy_ibt_plt->plt_entry,
 			       non_lazy_ibt_plt->plt_got_offset) == 0))
@@ -6860,6 +6865,9 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
       plts[j].contents = plt_contents;
     }
 
+  if (count == 0)
+    return -1;
+
   size = count * sizeof (asymbol);
   s = *ret = (asymbol *) bfd_zmalloc (size);
   if (s == NULL)


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