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Merge Fix parser lexer

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The lexer is broken and passing echo input to stdout that it doesn't match in some states ignoring the error.

First add `%option nodefault` to guarantee the lexer won't ever echo the unknown input to stdout, this will cause the parser to error out with

```
flex scanner jammed
```

and $?=2 if a profile contains unknown/invalid parts. That's not really a helpful error message, but still better than ignoring errors.

Next improve the error message output,

```
AppArmor parser error for tst/simple_tests//vars/vars_simple_assignment_14.sd line 8: Lexer found unexpected character: '
' (0xa) in state: SUB_ID_WS
```

using flex's error output only if there is an mistake made when introducing new states.

Finally fix bugs that are found.

MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/569
Acked-by: Steve Beattie <steve.beattie@canonical.com>
This commit is contained in:
John Johansen 2020-06-12 22:36:15 +00:00
commit aeb1359b3d
2 changed files with 18 additions and 6 deletions
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23
parser/parser_lex.l
View file

@ -25,6 +25,7 @@
%option noyy_top_state
%option nounput
%option stack
%option nodefault
%{
#include <stdio.h>
@ -264,7 +265,16 @@ LT_EQUAL <=
LT <
GT >
/* IF adding new state please update state_names table at eof */
/* IF adding new state please update state_names table and default rule (just
* above the state_names table) at the eof.
*
* The nodefault option is set so missing adding to the default rule isn't
* fatal but can't take advantage of additional debug the default rule might
* have.
*
* If a state is not added to the default rule it can result in the message
* "flex scanner jammed"
*/
%x SUB_ID
%x SUB_ID_WS
%x SUB_VALUE
@ -466,6 +476,7 @@ GT >
\\\n { DUMP_PREPROCESS; current_lineno++ ; }
\r?\n {
/* don't use shared rule because we need POP() here */
DUMP_PREPROCESS;
current_lineno++;
POP();
@ -692,18 +703,20 @@ include/{WS} {
POP_NODUMP();
RETURN_TOKEN(TOK_END_OF_RULE);
}
}
\r?\n {
<INITIAL,SUB_ID_WS,INCLUDE,INCLUDE_EXISTS,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,RLIMIT_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,ABI_MODE>{
\r?\n {
DUMP_PREPROCESS;
current_lineno++;
}
}
<INITIAL,SUB_ID,SUB_ID_WS,SUB_VALUE,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,ASSIGN_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE>{
[^\n] {
<INITIAL,SUB_ID,SUB_ID_WS,SUB_VALUE,LIST_VAL_MODE,EXTCOND_MODE,LIST_COND_VAL,LIST_COND_PAREN_VAL,LIST_COND_MODE,EXTCONDLIST_MODE,ASSIGN_MODE,NETWORK_MODE,CHANGE_PROFILE_MODE,MOUNT_MODE,DBUS_MODE,SIGNAL_MODE,PTRACE_MODE,UNIX_MODE,RLIMIT_MODEINCLUDE,INCLUDE_EXISTS,ABI_MODE>{
(.|\n) {
DUMP_PREPROCESS;
/* Something we didn't expect */
yyerror(_("Found unexpected character: '%s'"), yytext);
yyerror(_("Lexer found unexpected character: '%s' (0x%x) in state: %s"), yytext, yytext[0], state_names[YY_START].c_str());
}
}
%%

1
parser/tst/simple_tests/abi/bad_1.sd
View file

@ -1,7 +1,6 @@
#
#=DESCRIPTION abi testing - abi relative path in quotes
#=EXRESULT FAIL
#=TODO
abi "simple_tests/includes/abi/4.19,