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vim-patch:9.0.0577: buffer underflow with unexpected :finally

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Problem:    Buffer underflow with unexpected :finally.
Solution:   Check CSF_TRY can be found.

96b9bf8f74

Co-authored-by: Bram Moolenaar <Bram@vim.org>
This commit is contained in:
zeertzjq 2022-12-03 20:53:43 +08:00
parent bf4bf7f9e0
commit 0cb90114d4
2 changed files with 262 additions and 239 deletions
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479
src/nvim/ex_eval.c
View File

@ -1420,108 +1420,107 @@ void ex_finally(exarg_T *eap)
int pending = CSTP_NONE;
cstack_T *const cstack = eap->cstack;
if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0) {
for (idx = cstack->cs_idx; idx >= 0; idx--) {
if (cstack->cs_flags[idx] & CSF_TRY) {
break;
}
}
if (cstack->cs_trylevel <= 0 || idx < 0) {
eap->errmsg = _("E606: :finally without :try");
} else {
if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
eap->errmsg = get_end_emsg(cstack);
for (idx = cstack->cs_idx - 1; idx > 0; idx--) {
if (cstack->cs_flags[idx] & CSF_TRY) {
break;
}
}
// Make this error pending, so that the commands in the following
// finally clause can be executed. This overrules also a pending
// ":continue", ":break", ":return", or ":finish".
pending = CSTP_ERROR;
} else {
idx = cstack->cs_idx;
return;
}
if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
eap->errmsg = get_end_emsg(cstack);
// Make this error pending, so that the commands in the following
// finally clause can be executed. This overrules also a pending
// ":continue", ":break", ":return", or ":finish".
pending = CSTP_ERROR;
}
if (cstack->cs_flags[idx] & CSF_FINALLY) {
// Give up for a multiple ":finally" and ignore it.
eap->errmsg = _("E607: multiple :finally");
return;
}
rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
&cstack->cs_looplevel);
// Don't do something when the corresponding try block never got active
// (because of an inactive surrounding conditional or after an error or
// interrupt or throw) or for a ":finally" without ":try" or a multiple
// ":finally". After every other error (did_emsg or the conditional
// errors detected above) or after an interrupt (got_int) or an
// exception (did_throw), the finally clause must be executed.
skip = !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);
if (!skip) {
// When debugging or a breakpoint was encountered, display the
// debug prompt (if not already done). The user then knows that the
// finally clause is executed.
if (dbg_check_skipped(eap)) {
// Handle a ">quit" debug command as if an interrupt had
// occurred before the ":finally". That is, discard the
// original exception and replace it by an interrupt
// exception.
(void)do_intthrow(cstack);
}
if (cstack->cs_flags[idx] & CSF_FINALLY) {
// Give up for a multiple ":finally" and ignore it.
eap->errmsg = _("E607: multiple :finally");
return;
}
rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
&cstack->cs_looplevel);
// If there is a preceding catch clause and it caught the exception,
// finish the exception now. This happens also after errors except
// when this is a multiple ":finally" or one not within a ":try".
// After an error or interrupt, this also discards a pending
// ":continue", ":break", ":finish", or ":return" from the preceding
// try block or catch clause.
cleanup_conditionals(cstack, CSF_TRY, false);
// Don't do something when the corresponding try block never got active
// (because of an inactive surrounding conditional or after an error or
// interrupt or throw) or for a ":finally" without ":try" or a multiple
// ":finally". After every other error (did_emsg or the conditional
// errors detected above) or after an interrupt (got_int) or an
// exception (did_throw), the finally clause must be executed.
skip = !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);
if (!skip) {
// When debugging or a breakpoint was encountered, display the
// debug prompt (if not already done). The user then knows that the
// finally clause is executed.
if (dbg_check_skipped(eap)) {
// Handle a ">quit" debug command as if an interrupt had
// occurred before the ":finally". That is, discard the
// original exception and replace it by an interrupt
// exception.
(void)do_intthrow(cstack);
// Make did_emsg, got_int, did_throw pending. If set, they overrule
// a pending ":continue", ":break", ":return", or ":finish". Then
// we have particularly to discard a pending return value (as done
// by the call to cleanup_conditionals() above when did_emsg or
// got_int is set). The pending values are restored by the
// ":endtry", except if there is a new error, interrupt, exception,
// ":continue", ":break", ":return", or ":finish" in the following
// finally clause. A missing ":endwhile", ":endfor" or ":endif"
// detected here is treated as if did_emsg and did_throw had
// already been set, respectively in case that the error is not
// converted to an exception, did_throw had already been unset.
// We must not set did_emsg here since that would suppress the
// error message.
if (pending == CSTP_ERROR || did_emsg || got_int || did_throw) {
if (cstack->cs_pending[cstack->cs_idx] == CSTP_RETURN) {
report_discard_pending(CSTP_RETURN,
cstack->cs_rettv[cstack->cs_idx]);
discard_pending_return(cstack->cs_rettv[cstack->cs_idx]);
}
// If there is a preceding catch clause and it caught the exception,
// finish the exception now. This happens also after errors except
// when this is a multiple ":finally" or one not within a ":try".
// After an error or interrupt, this also discards a pending
// ":continue", ":break", ":finish", or ":return" from the preceding
// try block or catch clause.
cleanup_conditionals(cstack, CSF_TRY, false);
// Make did_emsg, got_int, did_throw pending. If set, they overrule
// a pending ":continue", ":break", ":return", or ":finish". Then
// we have particularly to discard a pending return value (as done
// by the call to cleanup_conditionals() above when did_emsg or
// got_int is set). The pending values are restored by the
// ":endtry", except if there is a new error, interrupt, exception,
// ":continue", ":break", ":return", or ":finish" in the following
// finally clause. A missing ":endwhile", ":endfor" or ":endif"
// detected here is treated as if did_emsg and did_throw had
// already been set, respectively in case that the error is not
// converted to an exception, did_throw had already been unset.
// We must not set did_emsg here since that would suppress the
// error message.
if (pending == CSTP_ERROR || did_emsg || got_int || did_throw) {
if (cstack->cs_pending[cstack->cs_idx] == CSTP_RETURN) {
report_discard_pending(CSTP_RETURN,
cstack->cs_rettv[cstack->cs_idx]);
discard_pending_return(cstack->cs_rettv[cstack->cs_idx]);
}
if (pending == CSTP_ERROR && !did_emsg) {
pending |= (THROW_ON_ERROR ? CSTP_THROW : 0);
} else {
pending |= (did_throw ? CSTP_THROW : 0);
}
pending |= did_emsg ? CSTP_ERROR : 0;
pending |= got_int ? CSTP_INTERRUPT : 0;
assert(pending >= CHAR_MIN && pending <= CHAR_MAX);
cstack->cs_pending[cstack->cs_idx] = (char)pending;
// It's mandatory that the current exception is stored in the
// cstack so that it can be rethrown at the ":endtry" or be
// discarded if the finally clause is left by a ":continue",
// ":break", ":return", ":finish", error, interrupt, or another
// exception. When emsg() is called for a missing ":endif" or
// a missing ":endwhile"/":endfor" detected here, the
// exception will be discarded.
if (did_throw && cstack->cs_exception[cstack->cs_idx] != current_exception) {
internal_error("ex_finally()");
}
if (pending == CSTP_ERROR && !did_emsg) {
pending |= (THROW_ON_ERROR ? CSTP_THROW : 0);
} else {
pending |= (did_throw ? CSTP_THROW : 0);
}
pending |= did_emsg ? CSTP_ERROR : 0;
pending |= got_int ? CSTP_INTERRUPT : 0;
assert(pending >= CHAR_MIN && pending <= CHAR_MAX);
cstack->cs_pending[cstack->cs_idx] = (char)pending;
// Set CSL_HAD_FINA, so do_cmdline() will reset did_emsg,
// got_int, and did_throw and make the finally clause active.
// This will happen after emsg() has been called for a missing
// ":endif" or a missing ":endwhile"/":endfor" detected here, so
// that the following finally clause will be executed even then.
cstack->cs_lflags |= CSL_HAD_FINA;
// It's mandatory that the current exception is stored in the
// cstack so that it can be rethrown at the ":endtry" or be
// discarded if the finally clause is left by a ":continue",
// ":break", ":return", ":finish", error, interrupt, or another
// exception. When emsg() is called for a missing ":endif" or
// a missing ":endwhile"/":endfor" detected here, the
// exception will be discarded.
if (did_throw && cstack->cs_exception[cstack->cs_idx] != current_exception) {
internal_error("ex_finally()");
}
}
// Set CSL_HAD_FINA, so do_cmdline() will reset did_emsg,
// got_int, and did_throw and make the finally clause active.
// This will happen after emsg() has been called for a missing
// ":endif" or a missing ":endwhile"/":endfor" detected here, so
// that the following finally clause will be executed even then.
cstack->cs_lflags |= CSL_HAD_FINA;
}
}
@ -1534,165 +1533,167 @@ void ex_endtry(exarg_T *eap)
void *rettv = NULL;
cstack_T *const cstack = eap->cstack;
if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0) {
for (idx = cstack->cs_idx; idx >= 0; idx--) {
if (cstack->cs_flags[idx] & CSF_TRY) {
break;
}
}
if (cstack->cs_trylevel <= 0 || idx < 0) {
eap->errmsg = _("E602: :endtry without :try");
return;
}
// Don't do something after an error, interrupt or throw in the try
// block, catch clause, or finally clause preceding this ":endtry" or
// when an error or interrupt occurred after a ":continue", ":break",
// ":return", or ":finish" in a try block or catch clause preceding this
// ":endtry" or when the try block never got active (because of an
// inactive surrounding conditional or after an error or interrupt or
// throw) or when there is a surrounding conditional and it has been
// made inactive by a ":continue", ":break", ":return", or ":finish" in
// the finally clause. The latter case need not be tested since then
// anything pending has already been discarded.
bool skip = did_emsg || got_int || did_throw || !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);
if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
eap->errmsg = get_end_emsg(cstack);
// Find the matching ":try" and report what's missing.
rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
&cstack->cs_looplevel);
skip = true;
// If an exception is being thrown, discard it to prevent it from
// being rethrown at the end of this function. It would be
// discarded by the error message, anyway. Resets did_throw.
// This does not affect the script termination due to the error
// since "trylevel" is decremented after emsg() has been called.
if (did_throw) {
discard_current_exception();
}
// report eap->errmsg, also when there already was an error
did_emsg = false;
} else {
// Don't do something after an error, interrupt or throw in the try
// block, catch clause, or finally clause preceding this ":endtry" or
// when an error or interrupt occurred after a ":continue", ":break",
// ":return", or ":finish" in a try block or catch clause preceding this
// ":endtry" or when the try block never got active (because of an
// inactive surrounding conditional or after an error or interrupt or
// throw) or when there is a surrounding conditional and it has been
// made inactive by a ":continue", ":break", ":return", or ":finish" in
// the finally clause. The latter case need not be tested since then
// anything pending has already been discarded.
bool skip = did_emsg || got_int || did_throw || !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);
idx = cstack->cs_idx;
if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
eap->errmsg = get_end_emsg(cstack);
// If we stopped with the exception currently being thrown at this
// try conditional since we didn't know that it doesn't have
// a finally clause, we need to rethrow it after closing the try
// conditional.
if (did_throw
&& (cstack->cs_flags[idx] & CSF_TRUE)
&& !(cstack->cs_flags[idx] & CSF_FINALLY)) {
rethrow = true;
}
}
// Find the matching ":try" and report what's missing.
idx = cstack->cs_idx;
do {
idx--;
} while (idx > 0 && !(cstack->cs_flags[idx] & CSF_TRY));
rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
&cstack->cs_looplevel);
// If there was no finally clause, show the user when debugging or
// a breakpoint was encountered that the end of the try conditional has
// been reached: display the debug prompt (if not already done). Do
// this on normal control flow or when an exception was thrown, but not
// on an interrupt or error not converted to an exception or when
// a ":break", ":continue", ":return", or ":finish" is pending. These
// actions are carried out immediately.
if ((rethrow || (!skip
&& !(cstack->cs_flags[idx] & CSF_FINALLY)
&& !cstack->cs_pending[idx]))
&& dbg_check_skipped(eap)) {
// Handle a ">quit" debug command as if an interrupt had occurred
// before the ":endtry". That is, throw an interrupt exception and
// set "skip" and "rethrow".
if (got_int) {
skip = true;
// If an exception is being thrown, discard it to prevent it from
// being rethrown at the end of this function. It would be
// discarded by the error message, anyway. Resets did_throw.
// This does not affect the script termination due to the error
// since "trylevel" is decremented after emsg() has been called.
if (did_throw) {
discard_current_exception();
}
// report eap->errmsg, also when there already was an error
did_emsg = false;
} else {
idx = cstack->cs_idx;
// If we stopped with the exception currently being thrown at this
// try conditional since we didn't know that it doesn't have
// a finally clause, we need to rethrow it after closing the try
// conditional.
if (did_throw
&& (cstack->cs_flags[idx] & CSF_TRUE)
&& !(cstack->cs_flags[idx] & CSF_FINALLY)) {
(void)do_intthrow(cstack);
// The do_intthrow() call may have reset did_throw or
// cstack->cs_pending[idx].
rethrow = false;
if (did_throw && !(cstack->cs_flags[idx] & CSF_FINALLY)) {
rethrow = true;
}
}
}
// If there was no finally clause, show the user when debugging or
// a breakpoint was encountered that the end of the try conditional has
// been reached: display the debug prompt (if not already done). Do
// this on normal control flow or when an exception was thrown, but not
// on an interrupt or error not converted to an exception or when
// a ":break", ":continue", ":return", or ":finish" is pending. These
// actions are carried out immediately.
if ((rethrow || (!skip
&& !(cstack->cs_flags[idx] & CSF_FINALLY)
&& !cstack->cs_pending[idx]))
&& dbg_check_skipped(eap)) {
// Handle a ">quit" debug command as if an interrupt had occurred
// before the ":endtry". That is, throw an interrupt exception and
// set "skip" and "rethrow".
if (got_int) {
skip = true;
(void)do_intthrow(cstack);
// The do_intthrow() call may have reset did_throw or
// cstack->cs_pending[idx].
rethrow = false;
if (did_throw && !(cstack->cs_flags[idx] & CSF_FINALLY)) {
rethrow = true;
}
// If a ":return" is pending, we need to resume it after closing the
// try conditional; remember the return value. If there was a finally
// clause making an exception pending, we need to rethrow it. Make it
// the exception currently being thrown.
if (!skip) {
pending = cstack->cs_pending[idx];
cstack->cs_pending[idx] = CSTP_NONE;
if (pending == CSTP_RETURN) {
rettv = cstack->cs_rettv[idx];
} else if (pending & CSTP_THROW) {
current_exception = cstack->cs_exception[idx];
}
}
// Discard anything pending on an error, interrupt, or throw in the
// finally clause. If there was no ":finally", discard a pending
// ":continue", ":break", ":return", or ":finish" if an error or
// interrupt occurred afterwards, but before the ":endtry" was reached.
// If an exception was caught by the last of the catch clauses and there
// was no finally clause, finish the exception now. This happens also
// after errors except when this ":endtry" is not within a ":try".
// Restore "emsg_silent" if it has been reset by this try conditional.
(void)cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, true);
if (cstack->cs_idx >= 0 && (cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
cstack->cs_idx--;
}
cstack->cs_trylevel--;
if (!skip) {
report_resume_pending(pending,
(pending == CSTP_RETURN) ? rettv :
(pending & CSTP_THROW) ? (void *)current_exception : NULL);
switch (pending) {
case CSTP_NONE:
break;
// Reactivate a pending ":continue", ":break", ":return",
// ":finish" from the try block or a catch clause of this try
// conditional. This is skipped, if there was an error in an
// (unskipped) conditional command or an interrupt afterwards
// or if the finally clause is present and executed a new error,
// interrupt, throw, ":continue", ":break", ":return", or
// ":finish".
case CSTP_CONTINUE:
ex_continue(eap);
break;
case CSTP_BREAK:
ex_break(eap);
break;
case CSTP_RETURN:
do_return(eap, false, false, rettv);
break;
case CSTP_FINISH:
do_finish(eap, false);
break;
// When the finally clause was entered due to an error,
// interrupt or throw (as opposed to a ":continue", ":break",
// ":return", or ":finish"), restore the pending values of
// did_emsg, got_int, and did_throw. This is skipped, if there
// was a new error, interrupt, throw, ":continue", ":break",
// ":return", or ":finish". in the finally clause.
default:
if (pending & CSTP_ERROR) {
did_emsg = true;
}
}
// If a ":return" is pending, we need to resume it after closing the
// try conditional; remember the return value. If there was a finally
// clause making an exception pending, we need to rethrow it. Make it
// the exception currently being thrown.
if (!skip) {
pending = cstack->cs_pending[idx];
cstack->cs_pending[idx] = CSTP_NONE;
if (pending == CSTP_RETURN) {
rettv = cstack->cs_rettv[idx];
} else if (pending & CSTP_THROW) {
current_exception = cstack->cs_exception[idx];
if (pending & CSTP_INTERRUPT) {
got_int = true;
}
}
// Discard anything pending on an error, interrupt, or throw in the
// finally clause. If there was no ":finally", discard a pending
// ":continue", ":break", ":return", or ":finish" if an error or
// interrupt occurred afterwards, but before the ":endtry" was reached.
// If an exception was caught by the last of the catch clauses and there
// was no finally clause, finish the exception now. This happens also
// after errors except when this ":endtry" is not within a ":try".
// Restore "emsg_silent" if it has been reset by this try conditional.
(void)cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, true);
if (cstack->cs_idx >= 0 && (cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
cstack->cs_idx--;
}
cstack->cs_trylevel--;
if (!skip) {
report_resume_pending(pending,
(pending == CSTP_RETURN) ? rettv :
(pending & CSTP_THROW) ? (void *)current_exception : NULL);
switch (pending) {
case CSTP_NONE:
break;
// Reactivate a pending ":continue", ":break", ":return",
// ":finish" from the try block or a catch clause of this try
// conditional. This is skipped, if there was an error in an
// (unskipped) conditional command or an interrupt afterwards
// or if the finally clause is present and executed a new error,
// interrupt, throw, ":continue", ":break", ":return", or
// ":finish".
case CSTP_CONTINUE:
ex_continue(eap);
break;
case CSTP_BREAK:
ex_break(eap);
break;
case CSTP_RETURN:
do_return(eap, false, false, rettv);
break;
case CSTP_FINISH:
do_finish(eap, false);
break;
// When the finally clause was entered due to an error,
// interrupt or throw (as opposed to a ":continue", ":break",
// ":return", or ":finish"), restore the pending values of
// did_emsg, got_int, and did_throw. This is skipped, if there
// was a new error, interrupt, throw, ":continue", ":break",
// ":return", or ":finish". in the finally clause.
default:
if (pending & CSTP_ERROR) {
did_emsg = true;
}
if (pending & CSTP_INTERRUPT) {
got_int = true;
}
if (pending & CSTP_THROW) {
rethrow = true;
}
break;
if (pending & CSTP_THROW) {
rethrow = true;
}
break;
}
}
if (rethrow) {
// Rethrow the current exception (within this cstack).
do_throw(cstack);
}
if (rethrow) {
// Rethrow the current exception (within this cstack).
do_throw(cstack);
}
}

22
src/nvim/testdir/test_trycatch.vim
View File

@ -3,6 +3,7 @@
source check.vim
source shared.vim
source vim9.vim
"-------------------------------------------------------------------------------
" Test environment {{{1
@ -2007,6 +2008,27 @@ func Test_try_catch_errors()
call assert_fails('try | for i in range(5) | endif | endtry', 'E580:')
call assert_fails('try | while v:true | endtry', 'E170:')
call assert_fails('try | if v:true | endtry', 'E171:')
" this was using a negative index in cstack[]
let lines =<< trim END
try
for
if
endwhile
if
finally
END
call CheckScriptFailure(lines, 'E690:')
let lines =<< trim END
try
for
if
endwhile
if
endtry
END
call CheckScriptFailure(lines, 'E690:')
endfunc
" Test for verbose messages with :try :catch, and :finally {{{1