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bindat (strz): Error on null byte if packing variable-length string

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* lisp/emacs-lisp/bindat.el (strz): Signal an error if a null byte is
encountered while packing a string to a variable-length strz field.
* test/lisp/emacs-lisp/bindat-tests.el (strz): Add tests (bug#55938).
This commit is contained in:
Richard Hansen 2022-06-13 14:32:01 +02:00 • committed by Lars Ingebrigtsen
parent 86f30c972b
commit 86325f960a
2 changed files with 11 additions and 1 deletions
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5
lisp/emacs-lisp/bindat.el
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@ -444,6 +444,11 @@ e.g. corresponding to STRUCT.FIELD1[INDEX2].FIELD3..."
(let* ((v (string-to-unibyte v))
(len (length v)))
(dotimes (i len)
(when (= (aref v i) 0)
;; Alternatively we could pretend that this was the end of
;; the string and stop packing, but then bindat-length would
;; need to scan the input string looking for a null byte.
(error "Null byte encountered in input strz string"))
(aset bindat-raw (+ bindat-idx i) (aref v i)))
(setq bindat-idx (+ bindat-idx len 1))))

7
test/lisp/emacs-lisp/bindat-tests.el
View file

@ -240,7 +240,12 @@
(ert-deftest bindat-test--strz-varlen-pack ()
(should (equal (bindat-pack spec "") "\0"))
(should (equal (bindat-pack spec "abc") "abc\0")))
(should (equal (bindat-pack spec "abc") "abc\0"))
;; Null bytes in the input string break unpacking.
(should-error (bindat-pack spec "\0"))
(should-error (bindat-pack spec "\0x"))
(should-error (bindat-pack spec "x\0"))
(should-error (bindat-pack spec "x\0y")))
(ert-deftest bindat-test--strz-varlen-unpack ()
(should (equal (bindat-unpack spec "\0") ""))