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CHB:ELF: enable retrieval of last n bytes from section #228

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Merged
sipma merged 1 commit into from
Feb 26, 2026
Merged

CHB:ELF: enable retrieval of last n bytes from section #228

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4 changes: 2 additions & 2 deletions CodeHawk/CHB/bchlib/bCHVersion.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -95,8 +95,8 @@ end


let version = new version_info_t
~version:"0.6.0_20260122"
~date:"2026-01-22"
~version:"0.6.0_20260225"
~date:"2026-02-25"
~licensee: None
~maxfilesize: None
()
10 changes: 8 additions & 2 deletions CodeHawk/CHB/bchlibelf/bCHELFHeader.ml
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Expand Up @@ -6,7 +6,7 @@

Copyright (c) 2005-2020 Kestrel Technology LLC
Copyright (c) 2020 Henny Sipma
Copyright (c) 2021-2025 Aarno Labs LLC
Copyright (c) 2021-2026 Aarno Labs LLC

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
Expand Down Expand Up @@ -808,12 +808,18 @@ object(self)
match self#get_containing_section a with
| Some s ->
let diff = a#subtract_to_int s#get_vaddr in
(* In some cases the <= check may be problematic. If the section is the
last one in the file, or perhaps if there is a gap between this
section and the next, the check may succeed, but the retrieval of
the corresponding bytes may fail. However, a < check may result in
missing the last library stub in a plt section.*)
if Result.is_ok diff then
(TR.tget_ok diff) + size < s#get_size
(TR.tget_ok diff) + size <= s#get_size
else
raise
(BCH_failure
(LBLOCK [
STR __FILE__; STR ":"; INT __LINE__;
STR "ELFHeader:has_xsubstring: interal error: ";
STR "subtraction"]))
| _ -> false
Expand Down
22 changes: 21 additions & 1 deletion CodeHawk/CHB/bchlibelf/bCHELFTypes.mli
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@

Copyright (c) 2005-2020 Kestrel Technology LLC
Copyright (c) 2020 Henny Sipma
Copyright (c) 2021-2024 Aarno Labs LLC
Copyright (c) 2021-2026 Aarno Labs LLC

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
Expand Down Expand Up @@ -807,6 +807,11 @@ object
method get_executable_sections: (elf_section_header_int * string) list
method get_executable_segments: (elf_program_header_int * string) list
method get_string_at_address: doubleword_int -> string option

(** [get_xsubstring addr size] returns the string of bytes starting at
virtual address [addr] with length size bytes.
Note: see comment for has_xsubstring below
*)
method get_xsubstring: doubleword_int -> int -> string
method get_relocation: doubleword_int -> string option
method get_containing_section: doubleword_int -> elf_raw_section_int option
Expand All @@ -832,6 +837,21 @@ object

method is_uninitialized_data_address: doubleword_int -> bool
method is_global_offset_table_address: doubleword_int -> bool

(** [has_xsubstring addr size] returns true if the section that contains
virtual address [addr] has at least [size] bytes starting from address
[addr].

Note: the check performed is
[addr - section_start_address) + size <= section_size]
In some cases the less than equal check may be problematic: if the
section is the last section of the file, or perhaps if there is a
gap between this section and the next, the equal sign may make the
check succeed, but the retrieval of the corresponding bytes, by calling
[get_xsubstring] with the same arguments, may fail.
However, if a less-than check is used the last library stub in a plt
may be missed.
*)
method has_xsubstring: doubleword_int -> int -> bool
method has_debug_info: bool
method has_debug_abbrev: bool
Expand Down