Skip to content

mruby-pack: check the pack("U") range before the cast to uint32_t #7114

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
matz merged 1 commit into from
Aug 12, 2026
Merged

mruby-pack: check the pack("U") range before the cast to uint32_t #7114

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 6 additions & 3 deletions mrbgems/mruby-pack/src/pack.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -775,12 +775,15 @@ pack_utf8(mrb_state *mrb, mrb_value o, mrb_value str, mrb_int sidx, int count, u
{
char utf8[4];
int len;
uint32_t c = (uint32_t)mrb_integer(o);
mrb_int c = mrb_integer(o);

len = (int)mrb_utf8_to_buf(utf8, c);
if (len == 0) {
/* mrb_utf8_to_buf() takes a uint32_t, which wraps a value outside the
Unicode range into a codepoint, so the range has to be checked on the
mrb_int before the cast. */
if (c < 0 || 0x10FFFF < c) {
mrb_raise(mrb, E_RANGE_ERROR, "pack(U): value out of range");
}
len = (int)mrb_utf8_to_buf(utf8, (uint32_t)c);

str = str_len_ensure(mrb, str, sidx + len);
memcpy(RSTRING_PTR(str) + sidx, utf8, len);
Expand Down
13 changes: 13 additions & 0 deletions mrbgems/mruby-pack/test/pack.rb
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -210,6 +210,19 @@ def assert_pack tmpl, packed, unpacked
assert_raise(RangeError) { [0x40000000].pack("U") }
end

assert 'pack("U") with a value outside the Unicode range' do
assert_equal [0xF4, 0x8F, 0xBF, 0xBF], [0x10FFFF].pack("U").unpack("C*")
assert_raise(RangeError) { [0x110000].pack("U") }

# The encoder takes a uint32_t, so a value that wraps into the Unicode range
# must not come out as the character it wraps to. The shift is computed at
# run time because the constant folder would reject the literal on a build
# with a 32-bit mrb_int and no bigint, where there is nothing to test.
shift = 32
wrapping = ((1 << shift) + 0x41) rescue nil
assert_raise(RangeError) { [wrapping].pack("U") } if wrapping.is_a?(Integer)
end

assert 'unpack1' do
d = 1234
assert_equal(d, [d].pack("i").unpack1("i"))
Expand Down
Loading