From: usa@... Date: 2016-03-25T09:25:26+00:00 Subject: [ruby-core:74559] [Ruby trunk Bug#12192] Wrong nth_ref_max check in parse.y Issue #12192 has been updated by Usaku NAKAMURA. Backport changed from 2.1: REQUIRED, 2.2: REQUIRED, 2.3: REQUIRED to 2.1: DONE, 2.2: REQUIRED, 2.3: REQUIRED ruby_2_1 r54275 merged revision(s) 54172. ---------------------------------------- Bug #12192: Wrong nth_ref_max check in parse.y https://bugs.ruby-lang.org/issues/12192#change-57686 * Author: Victor Nawothnig * Status: Closed * Priority: Normal * Assignee: * ruby -v: 2.3.0 * Backport: 2.1: DONE, 2.2: REQUIRED, 2.3: REQUIRED ---------------------------------------- ~~~ $ ruby -e 'a = $1073741824' -e: integer 2147483648 too big to convert to `int' (RangeError) ~~~ The following is a stack trace from the issue: ~~~ * thread #1: tid = 0x91034, 0x00000001000e52d8 ruby`rb_out_of_int(num=2147483648) + 40 at numeric.c:2379, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1 * frame #0: 0x00000001000e52d8 ruby`rb_out_of_int(num=2147483648) + 40 at numeric.c:2379 frame #1: 0x00000001000e5358 ruby`check_int(num=2147483648) + 40 at numeric.c:2387 frame #2: 0x00000001000e53b1 ruby`rb_fix2int(val=4294967297) + 81 at numeric.c:2420 frame #3: 0x00000001002292e0 ruby`iseq_set_sequence(iseq=0x00000001018b36a0, anchor=0x00007fff5fbfeea0) + 1504 at compile.c:1661 frame #4: 0x0000000100224741 ruby`iseq_setup(iseq=0x00000001018b36a0, anchor=0x00007fff5fbfeea0) + 161 at compile.c:1122 frame #5: 0x000000010021544f ruby`rb_iseq_compile_node(iseq=0x00000001018b36a0, node=0x00000001018b3998) + 3071 at compile.c:643 ~~~ The error is platform-dependent, but is reproduceable on OSX using LLVM/Clang. The following 2 steps cause this error: 1. iseq_compile_each wraps `n` inside a VALUE using INT2FIX 2. iseq_set_sequence/vm_getspecial unwraps `n` using FIX2INT, checking for loss of information during casting The reason that check fails is because n gets left-shifted before being passed to INT2FIX for the back-ref flag. That means n must not be larger than INT_MAX >> 1. parse_numvar from parse.y contains an a wrong limit on systems where sizeof(long) == sizeof(int) The fix is simple, parse.y needs to use the following boundary for checking: nth_ref_max = ((FIXNUM_MAX < INT_MAX) ? FIXNUM_MAX : INT_MAX) >> 1; -- https://bugs.ruby-lang.org/ Unsubscribe: