[binutils-gdb] x86: Check plt_got_offset for lazy IBT PLT

[H.J. Lu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=aad80d24d29efc2cb5d80f33f7ee127e918ba34f

commit aad80d24d29efc2cb5d80f33f7ee127e918ba34f
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Sep 2 11:26:57 2025 -0700

    x86: Check plt_got_offset for lazy IBT PLT
    
    Lazy IBT PLT entries look like
    
    static const bfd_byte elf_i386_lazy_ibt_plt_entry[LAZY_PLT_ENTRY_SIZE] =
    {
      0xf3, 0x0f, 0x1e, 0xfb,       /* endbr32                    */
      0x68, 0, 0, 0, 0,             /* pushl immediate            */
      0xe9, 0, 0, 0, 0,             /* jmp relative               */
      0x66, 0x90                    /* xchg %ax,%ax               */
    };
    
    static const bfd_byte elf_x86_64_lazy_ibt_plt_entry[LAZY_PLT_ENTRY_SIZE] =
    {
      0xf3, 0x0f, 0x1e, 0xfa,       /* endbr64                    */
      0x68, 0, 0, 0, 0,             /* pushq immediate            */
      0xe9, 0, 0, 0, 0,             /* jmpq relative              */
      0x66, 0x90                    /* xchg %ax,%ax               */
    };
    
    They only have
    
    unsigned int plt_reloc_offset;  /* ... offset into relocation table. */
    
    and don't have
    
    unsigned int plt_got_offset;    /* ... address of this symbol in .got. */
    
    We should use plt_reloc_offset, not plt_got_offset, to check IBT PLT.
    
            PR binutils/33358
            * elf32-i386.c (elf_i386_get_synthetic_symtab): Check
            plt_reloc_offset for lazy IBT PLT.
            * elf64-x86-64.c (elf_x86_64_get_synthetic_symtab): Likewise.
    
    Signed-off-by: H.J. Lu <hjl.tools@gmail.com>

Diff:
---
 bfd/elf32-i386.c   | 4 ++--
 bfd/elf64-x86-64.c | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index 4b99b8e0202..e375e18d5fe 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -4354,7 +4354,7 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	      if (lazy_ibt_plt != NULL
 		  && (memcmp (plt_contents + lazy_ibt_plt->plt0_entry_size,
 			      lazy_ibt_plt->plt_entry,
-			      lazy_ibt_plt->plt_got_offset) == 0))
+			      lazy_ibt_plt->plt_reloc_offset) == 0))
 		plt_type = plt_lazy | plt_second;
 	      else
 		plt_type = plt_lazy;
@@ -4367,7 +4367,7 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
 	      if (lazy_ibt_plt != NULL
 		  && (memcmp (plt_contents + lazy_ibt_plt->plt0_entry_size,
 			      lazy_ibt_plt->pic_plt_entry,
-			      lazy_ibt_plt->plt_got_offset) == 0))
+			      lazy_ibt_plt->plt_reloc_offset) == 0))
 		plt_type = plt_lazy | plt_pic | plt_second;
 	      else
 		plt_type = plt_lazy | plt_pic;
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index 4f0e97c4a9a..00586455203 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -5852,7 +5852,7 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
 	    {
 	      if (memcmp (plt_contents + lazy_ibt_plt->plt_entry_size,
 			  lazy_ibt_plt->plt_entry,
-			  lazy_ibt_plt->plt_got_offset) == 0)
+			  lazy_ibt_plt->plt_reloc_offset) == 0)
 		{
 		  /* The fist entry in the lazy IBT PLT is the same as
 		     the lazy PLT.  */
@@ -5874,7 +5874,7 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
 	      if (memcmp (plt_contents
 			  + lazy_bnd_ibt_plt->plt_entry_size,
 			  lazy_bnd_ibt_plt->plt_entry,
-			  lazy_bnd_ibt_plt->plt_got_offset) == 0)
+			  lazy_bnd_ibt_plt->plt_reloc_offset) == 0)
 		lazy_plt = lazy_bnd_ibt_plt;
 	      else
 		lazy_plt = lazy_bnd_plt;