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185 lines
7.3 KiB
185 lines
7.3 KiB
From 6eb257e5c731c691eb137fca94e916ca73941a5a Mon Sep 17 00:00:00 2001
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From: Michael Catanzaro <mcatanzaro@gnome.org>
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Date: Fri, 31 Jul 2020 15:21:53 -0500
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Subject: [PATCH] parser: limit recursion in block and any productions
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If we don't have any limits, we can recurse forever and overflow the
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stack.
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Fixes #8
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---
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src/cr-parser.c | 44 +++++++++++++++++++++++++++++---------------
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1 file changed, 29 insertions(+), 15 deletions(-)
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diff --git a/src/cr-parser.c b/src/cr-parser.c
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index 18c9a01..f4a62e3 100644
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--- a/src/cr-parser.c
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+++ b/src/cr-parser.c
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@@ -136,6 +136,8 @@ struct _CRParserPriv {
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#define CHARS_TAB_SIZE 12
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+#define RECURSIVE_CALLERS_LIMIT 100
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+
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/**
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* IS_NUM:
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*@a_char: the char to test.
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@@ -344,9 +346,11 @@ static enum CRStatus cr_parser_parse_selector_core (CRParser * a_this);
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static enum CRStatus cr_parser_parse_declaration_core (CRParser * a_this);
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-static enum CRStatus cr_parser_parse_any_core (CRParser * a_this);
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+static enum CRStatus cr_parser_parse_any_core (CRParser * a_this,
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+ guint n_calls);
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-static enum CRStatus cr_parser_parse_block_core (CRParser * a_this);
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+static enum CRStatus cr_parser_parse_block_core (CRParser * a_this,
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+ guint n_calls);
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static enum CRStatus cr_parser_parse_value_core (CRParser * a_this);
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@@ -784,7 +788,7 @@ cr_parser_parse_atrule_core (CRParser * a_this)
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cr_parser_try_to_skip_spaces_and_comments (a_this);
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do {
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, 0);
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} while (status == CR_OK);
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status = cr_tknzr_get_next_token (PRIVATE (a_this)->tknzr,
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@@ -795,7 +799,7 @@ cr_parser_parse_atrule_core (CRParser * a_this)
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cr_tknzr_unget_token (PRIVATE (a_this)->tknzr,
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token);
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token = NULL;
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- status = cr_parser_parse_block_core (a_this);
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+ status = cr_parser_parse_block_core (a_this, 0);
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CHECK_PARSING_STATUS (status,
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FALSE);
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goto done;
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@@ -930,11 +934,11 @@ cr_parser_parse_selector_core (CRParser * a_this)
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RECORD_INITIAL_POS (a_this, &init_pos);
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, 0);
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CHECK_PARSING_STATUS (status, FALSE);
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do {
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, 0);
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} while (status == CR_OK);
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@@ -956,10 +960,12 @@ cr_parser_parse_selector_core (CRParser * a_this)
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*in chapter 4.1 of the css2 spec.
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*block ::= '{' S* [ any | block | ATKEYWORD S* | ';' ]* '}' S*;
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*@param a_this the current instance of #CRParser.
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+ *@param n_calls used to limit recursion depth
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*FIXME: code this function.
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*/
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static enum CRStatus
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-cr_parser_parse_block_core (CRParser * a_this)
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+cr_parser_parse_block_core (CRParser * a_this,
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+ guint n_calls)
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{
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CRToken *token = NULL;
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CRInputPos init_pos;
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@@ -967,6 +973,9 @@ cr_parser_parse_block_core (CRParser * a_this)
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g_return_val_if_fail (a_this && PRIVATE (a_this), CR_BAD_PARAM_ERROR);
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+ if (n_calls > RECURSIVE_CALLERS_LIMIT)
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+ return CR_ERROR;
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+
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RECORD_INITIAL_POS (a_this, &init_pos);
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status = cr_tknzr_get_next_token (PRIVATE (a_this)->tknzr, &token);
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@@ -996,13 +1005,13 @@ cr_parser_parse_block_core (CRParser * a_this)
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} else if (token->type == CBO_TK) {
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cr_tknzr_unget_token (PRIVATE (a_this)->tknzr, token);
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token = NULL;
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- status = cr_parser_parse_block_core (a_this);
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+ status = cr_parser_parse_block_core (a_this, n_calls + 1);
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CHECK_PARSING_STATUS (status, FALSE);
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goto parse_block_content;
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} else {
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cr_tknzr_unget_token (PRIVATE (a_this)->tknzr, token);
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token = NULL;
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, n_calls + 1);
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CHECK_PARSING_STATUS (status, FALSE);
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goto parse_block_content;
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}
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@@ -1109,7 +1118,7 @@ cr_parser_parse_value_core (CRParser * a_this)
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status = cr_tknzr_unget_token (PRIVATE (a_this)->tknzr,
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token);
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token = NULL;
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- status = cr_parser_parse_block_core (a_this);
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+ status = cr_parser_parse_block_core (a_this, 0);
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CHECK_PARSING_STATUS (status, FALSE);
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ref++;
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goto continue_parsing;
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@@ -1123,7 +1132,7 @@ cr_parser_parse_value_core (CRParser * a_this)
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status = cr_tknzr_unget_token (PRIVATE (a_this)->tknzr,
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token);
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token = NULL;
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, 0);
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if (status == CR_OK) {
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ref++;
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goto continue_parsing;
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@@ -1162,10 +1171,12 @@ cr_parser_parse_value_core (CRParser * a_this)
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* | FUNCTION | DASHMATCH | '(' any* ')' | '[' any* ']' ] S*;
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*
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*@param a_this the current instance of #CRParser.
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+ *@param n_calls used to limit recursion depth
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*@return CR_OK upon successfull completion, an error code otherwise.
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*/
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static enum CRStatus
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-cr_parser_parse_any_core (CRParser * a_this)
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+cr_parser_parse_any_core (CRParser * a_this,
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+ guint n_calls)
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{
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CRToken *token1 = NULL,
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*token2 = NULL;
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@@ -1174,6 +1185,9 @@ cr_parser_parse_any_core (CRParser * a_this)
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g_return_val_if_fail (a_this, CR_BAD_PARAM_ERROR);
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+ if (n_calls > RECURSIVE_CALLERS_LIMIT)
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+ return CR_ERROR;
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+
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RECORD_INITIAL_POS (a_this, &init_pos);
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status = cr_tknzr_get_next_token (PRIVATE (a_this)->tknzr, &token1);
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@@ -1212,7 +1226,7 @@ cr_parser_parse_any_core (CRParser * a_this)
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*We consider parameter as being an "any*" production.
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*/
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do {
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, n_calls + 1);
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} while (status == CR_OK);
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ENSURE_PARSING_COND (status == CR_PARSING_ERROR);
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@@ -1237,7 +1251,7 @@ cr_parser_parse_any_core (CRParser * a_this)
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}
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do {
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, n_calls + 1);
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} while (status == CR_OK);
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ENSURE_PARSING_COND (status == CR_PARSING_ERROR);
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@@ -1265,7 +1279,7 @@ cr_parser_parse_any_core (CRParser * a_this)
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}
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do {
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- status = cr_parser_parse_any_core (a_this);
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+ status = cr_parser_parse_any_core (a_this, n_calls + 1);
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} while (status == CR_OK);
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ENSURE_PARSING_COND (status == CR_PARSING_ERROR);
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--
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GitLab
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