Regex match on a variable is not working if length is long

[Alan DeKok]

On Dec 11, 2019, at 4:06 AM, Chinnapaiyan, Nagamani <Nagamani.Chinnapaiyan at viasat.com> wrote:
> But this one is not,
> 
> (15)        if ( "%{control:Tmp-String-7}" =~ /vendor-options.*\(number 43\)\(value (([0-9a-fA-F]{2}:)*[0-9a-fA-F]{2})/ ) {
> 
> (15)          EXPAND %{control:Tmp-String-7}
> 
> (15)             --> ((ClassName Policy)(name client-policy:1,6,00:A0:BC:6C:7D:3A)(v4-reply-options [vendor-encapsulated-options])(vendor-options [((ClassName Option)(number 43)(value 01:03:00:A0:BC:02:09:55:54:00:00:00:00:00:00:07:03:0E:55:54:32:00:00:00:00:00:03:07:03:0A:00:09:04:11:55:54:5F:33:2E:37:2E:33:2E:31:30:2E:39:2E:62:69:6E:05:04:0A:4F:FF:0F:14:44:01:00:02:01:03:11:05:00:44:00:44:07:00:43:00:43:01:01:02:01:03:06:07:01:BD:01:BD:01:01:02:01:07:00:87:00:88:01:01:02:01:06:C0:A8:64:00:18:07:00:16:00:17:01:01:02:01:03:11:06:C0:A8:64:00:18:07:00:A1:00:A1:19:01:01:26:42:68:74:74:70:3A:2F:2F:61:63:73:2E:64:65:76:2E:63:6D:74:2E:76:69:61:73:61:74:2E:69:6F:3A:39:36:37:35:2F:6C:69:76:65:2F:43:50:45:4D:61:6E:61:67:65:72:2F:43:50:45:73:2F:67:65:6E:65:72:69:63:54:52:36:39:27:02:00:05:28:02:07:D0:2A:0E:55:54:2E:35:2E:32:2E:32:2E:31:30:35:30:33:2B:04:0A:4F:FF:0F:2C:0E:55:54:2E:35:2E:32:2E:32:2E:31:30:33:39:33:33:0C:55:54:32:00:00:00:00:00:00:00:29:08:36:01:FF:3B:0E:55:54:32:00:00:00:00:00:03:07:03:0A:00:09:3C:12:55:54:32:5F:33:2E:37:2E:33:2E:31:30:2E:39:2E:62:69:6E:3D:04:0A:4F:FF:0F:3E:3C:68:74:74:70:3A:2F:2F:31:30:2E:37:39:2E:32:35:35:2E:31:36:2F:70:75:62:2F:76:77:61:5F:69:6D:61:67:65:73:2F:76:77:61:5F:55:54:2E:35:2E:32:2E:32:2E:31:30:35:30:33:2E:74:61:72:2E:67:7A:3F:3C:68:74:74:70:3A:2F:2F:31:30:2E:37:39:2E:32:35:35:2E:31:36:2F:70:75:62:2F:76:77:61:5F:69:6D:61:67:65:73:2F:76:77:61:5F:55:54:2E:35:2E:32:2E:32:2E:31:30:33:39:33:2E:74:61:72:2E:67:7A:40:01:00)(option-definition-set-name ViasatUT))]))
> 
> (15)          ERROR: regex failed: regex evaluation failed with code (-27): <INVALID>

  Hmm... I've pushed a change which should get you an actual error message.  That may help.

> Both are same conditions with different values in them. Why second one is not working?

  There's an internal error inside of PCRE.  We don't know what error until we see it in a debug message.

  My guess is that the internal JIT stack for PCRE is too small.  One regex will work for small data, but the same regex will overflow the internal JIT stack for large data.

  There's a line in src/lib/util/regex.c:

		tls->jit_stack = pcre2_jit_stack_create(32 * 1024, 512 * 1024, tls->gcontext);

  Change it to something like:

		tls->jit_stack = pcre2_jit_stack_create(32 * 1024, 4 * 1024 * 1024, tls->gcontext);

  That will greatly increase the size of the JIT stack.  If that fixes it, then that's the problem.

  Alan DeKok.