[binutils-gdb] bfd: Avoid signed overflow for new_size adjustment

[binutils-gdb] bfd: Avoid signed overflow for new_size adjustment

[H.J. Lu]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=e25466730d436937e814f80b69e5d124513fff03

commit e25466730d436937e814f80b69e5d124513fff03
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Tue Dec 6 12:54:43 2022 -0800

    bfd: Avoid signed overflow for new_size adjustment
    
    When bfd_size_type is unsigned 64-bit integer and sizeof is unsigned
    32-bit integer, subtraction in
    
    *new_size += sizeof (Elf32_External_Chdr) - sizeof (Elf64_External_Chdr);
    
    will overflow.  Use
    
    *new_size -= sizeof (Elf64_External_Chdr) - sizeof (Elf32_External_Chdr);
    
    to avoid overflow.
    
            PR binutils/29860
            * compress.c (bfd_convert_section_setup): Avoid signed overflow
            for new_size adjustment.

Diff:
---
 bfd/compress.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bfd/compress.c b/bfd/compress.c
index bb55a6ec0ac..5ea7cd95f3a 100644
--- a/bfd/compress.c
+++ b/bfd/compress.c
@@ -306,7 +306,7 @@ bfd_convert_section_setup (bfd *ibfd, asection *isec, bfd *obfd,
   if (hdr_size == sizeof (Elf32_External_Chdr))
     *new_size += sizeof (Elf64_External_Chdr) - sizeof (Elf32_External_Chdr);
   else
-    *new_size += sizeof (Elf32_External_Chdr) - sizeof (Elf64_External_Chdr);
+    *new_size -= sizeof (Elf64_External_Chdr) - sizeof (Elf32_External_Chdr);
   return true;
 }