libutils/Unicode.cpp: Correct length computation and add checks for utf16->utf8
Inconsistent behaviour between utf16_to_utf8 and utf16_to_utf8_length
is causing a heap overflow.
Correcting the length computation and adding bound checks to the
conversion functions.
Test: ran libutils_tests
Bug: 29250543
Change-Id: I6115e3357141ed245c63c6eb25fc0fd0a9a7a2bb
(cherry picked from commit c4966a363e46d2e1074d1a365e232af0dcedd6a1)
diff --git a/include/utils/Unicode.h b/include/utils/Unicode.h
index b76a5e2..4e17cc3 100644
--- a/include/utils/Unicode.h
+++ b/include/utils/Unicode.h
@@ -87,7 +87,7 @@
* "dst" becomes \xE3\x81\x82\xE3\x81\x84
* (note that "dst" is NOT null-terminated, like strncpy)
*/
-void utf32_to_utf8(const char32_t* src, size_t src_len, char* dst);
+void utf32_to_utf8(const char32_t* src, size_t src_len, char* dst, size_t dst_len);
/**
* Returns the unicode value at "index".
@@ -109,7 +109,7 @@
* enough to fit the UTF-16 as measured by utf16_to_utf8_length with an added
* NULL terminator.
*/
-void utf16_to_utf8(const char16_t* src, size_t src_len, char* dst);
+void utf16_to_utf8(const char16_t* src, size_t src_len, char* dst, size_t dst_len);
/**
* Returns the length of "src" when "src" is valid UTF-8 string.