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bindat (str, strz): Reject non-ASCII, non-`eight-bit' characters

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* lisp/emacs-lisp/bindat.el (str) (strz): Signal an error if the user
attempts to pack a multibyte string containing characters other than
ASCII and `eight-bit' characters (bug#55897).
* doc/lispref/processes.texi (Bindat Types): Update documentation.
* test/lisp/emacs-lisp/bindat-tests.el (str) (strz): Add tests.
This commit is contained in:
Richard Hansen 2022-06-12 01:19:43 -04:00 • committed by Eli Zaretskii
parent c2695621fc
commit c1829b307c
3 changed files with 32 additions and 8 deletions
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14
doc/lispref/processes.texi
View file

@ -3486,8 +3486,11 @@ When packing, the first @var{len} bytes of the input string are copied
to the packed output. If the input string is shorter than @var{len},
the remaining bytes will be null (zero) unless a pre-allocated string
was provided to @code{bindat-pack}, in which case the remaining bytes
are left unmodified. When unpacking, any null bytes in the packed
input string will appear in the unpacked output.
are left unmodified. If the input string is multibyte with only ASCII
and @code{eight-bit} characters, it is converted to unibyte before it
is packed; other multibyte strings signal an error. When unpacking,
any null bytes in the packed input string will appear in the unpacked
output.
@item strz &optional @var{len}
If @var{len} is not provided: Variable-length null-terminated unibyte
@ -3497,8 +3500,11 @@ null (zero) unless a pre-allocated string was provided to
@code{bindat-pack}, in which case that byte is left unmodified. The
length of the packed output is the length of the input string plus one
(for the null terminator). The input string must not contain any null
bytes. When unpacking, the resulting string contains all bytes up to
(but excluding) the null byte.
bytes. If the input string is multibyte with only ASCII and
@code{eight-bit} characters, it is converted to unibyte before it is
packed; other multibyte strings signal an error. When unpacking, the
resulting string contains all bytes up to (but excluding) the null
byte.
@quotation Caution
If a pre-allocated string is provided to @code{bindat-pack}, the

10
lisp/emacs-lisp/bindat.el
View file

@ -435,12 +435,14 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..."
(bindat--pack-u32r (ash v -32)))
(defun bindat--pack-str (len v)
(dotimes (i (min len (length v)))
(aset bindat-raw (+ bindat-idx i) (aref v i)))
(setq bindat-idx (+ bindat-idx len)))
(let ((v (string-to-unibyte v)))
(dotimes (i (min len (length v)))
(aset bindat-raw (+ bindat-idx i) (aref v i)))
(setq bindat-idx (+ bindat-idx len))))
(defun bindat--pack-strz (v)
(let ((len (length v)))
(let* ((v (string-to-unibyte v))
(len (length v)))
(dotimes (i len)
(aset bindat-raw (+ bindat-idx i) (aref v i)))
(setq bindat-idx (+ bindat-idx len 1))))

16
test/lisp/emacs-lisp/bindat-tests.el
View file

@ -188,6 +188,22 @@
(apply #'bindat-pack (append (car tc) (list prealloc)))
(should (equal prealloc (cdr tc))))))
(ert-deftest bindat-test--str-strz-multibyte ()
(dolist (spec (list (bindat-type str 2)
(bindat-type strz 2)
(bindat-type strz)))
(should (equal (bindat-pack spec (string-to-multibyte "x")) "x\0"))
(should (equal (bindat-pack spec (string-to-multibyte "\xff")) "\xff\0"))
(should-error (bindat-pack spec "💩"))
(should-error (bindat-pack spec "\N{U+ff}")))
(dolist (spec (list '((x str 2)) '((x strz 2))))
(should (equal (bindat-pack spec `((x . ,(string-to-multibyte "x"))))
"x\0"))
(should (equal (bindat-pack spec `((x . ,(string-to-multibyte "\xff"))))
"\xff\0"))
(should-error (bindat-pack spec '((x . "💩"))))
(should-error (bindat-pack spec '((x . "\N{U+ff}"))))))
(let ((spec (bindat-type strz 2)))
(ert-deftest bindat-test--strz-fixedlen-len ()
(should (equal (bindat-length spec "") 2))