[Forensics-changes] [yara] 22/368: Filter out invalid characters in hex strings
Hilko Bengen
bengen at moszumanska.debian.org
Sat Jul 1 10:30:06 UTC 2017
This is an automated email from the git hooks/post-receive script.
bengen pushed a commit to annotated tag v3.5.0
in repository yara.
commit 113bef392b2cc310cca19d8f825da9922de856a6
Author: Victor M. Alvarez <plusvic at gmail.com>
Date: Fri Jul 3 11:27:55 2015 +0200
Filter out invalid characters in hex strings
---
libyara/hex_lexer.c | 127 ++++++++++++++++++++++++++++------------------------
libyara/hex_lexer.l | 40 ++++++++---------
2 files changed, 88 insertions(+), 79 deletions(-)
diff --git a/libyara/hex_lexer.c b/libyara/hex_lexer.c
index 88f7bca..6ca0232 100644
--- a/libyara/hex_lexer.c
+++ b/libyara/hex_lexer.c
@@ -370,8 +370,8 @@ static void yy_fatal_error (yyconst char msg[] ,yyscan_t yyscanner );
*yy_cp = '\0'; \
yyg->yy_c_buf_p = yy_cp;
-#define YY_NUM_RULES 12
-#define YY_END_OF_BUFFER 13
+#define YY_NUM_RULES 14
+#define YY_END_OF_BUFFER 15
/* This struct is not used in this scanner,
but its presence is necessary. */
struct yy_trans_info
@@ -379,11 +379,11 @@ struct yy_trans_info
flex_int32_t yy_verify;
flex_int32_t yy_nxt;
};
-static yyconst flex_int16_t yy_accept[23] =
+static yyconst flex_int16_t yy_accept[25] =
{ 0,
- 0, 0, 0, 0, 13, 11, 10, 10, 11, 11,
- 5, 12, 6, 7, 8, 9, 1, 2, 3, 4,
- 8, 0
+ 0, 0, 0, 0, 15, 13, 11, 11, 12, 13,
+ 13, 5, 10, 9, 9, 6, 7, 8, 1, 2,
+ 3, 4, 7, 0
} ;
static yyconst flex_int32_t yy_ec[256] =
@@ -391,8 +391,8 @@ static yyconst flex_int32_t yy_ec[256] =
1, 1, 1, 1, 1, 1, 1, 1, 2, 3,
1, 1, 2, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- 1, 2, 1, 1, 1, 1, 1, 1, 1, 1,
- 1, 1, 1, 1, 4, 5, 1, 6, 6, 6,
+ 1, 2, 1, 1, 1, 1, 1, 1, 1, 4,
+ 4, 1, 1, 1, 5, 1, 1, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 1, 1, 1,
1, 1, 7, 1, 8, 8, 8, 8, 8, 8,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
@@ -401,7 +401,7 @@ static yyconst flex_int32_t yy_ec[256] =
8, 8, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 4, 4, 4, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
@@ -423,40 +423,40 @@ static yyconst flex_int32_t yy_meta[11] =
1, 1, 1, 1, 1, 2, 2, 2, 1, 1
} ;
-static yyconst flex_int16_t yy_base[26] =
+static yyconst flex_int16_t yy_base[27] =
{ 0,
- 0, 0, 7, 14, 27, 28, 28, 28, 16, 15,
- 28, 28, 28, 28, 15, 28, 28, 28, 28, 28,
- 10, 28, 24, 13, 12
+ 0, 0, 10, 0, 27, 28, 28, 28, 28, 19,
+ 18, 28, 28, 28, 28, 28, 18, 28, 28, 28,
+ 28, 28, 17, 28, 20, 19
} ;
-static yyconst flex_int16_t yy_def[26] =
+static yyconst flex_int16_t yy_def[27] =
{ 0,
- 22, 1, 23, 23, 22, 22, 22, 22, 24, 25,
- 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
- 22, 0, 22, 22, 22
+ 24, 1, 24, 3, 24, 24, 24, 24, 24, 25,
+ 26, 24, 24, 24, 24, 24, 24, 24, 24, 24,
+ 24, 24, 24, 0, 24, 24
} ;
static yyconst flex_int16_t yy_nxt[39] =
{ 0,
- 6, 7, 8, 6, 6, 9, 10, 9, 11, 6,
- 13, 14, 15, 19, 17, 21, 16, 13, 14, 15,
- 21, 20, 18, 16, 12, 12, 22, 5, 22, 22,
- 22, 22, 22, 22, 22, 22, 22, 22
+ 6, 7, 8, 9, 6, 10, 11, 10, 12, 6,
+ 13, 14, 15, 13, 16, 17, 13, 13, 13, 18,
+ 21, 19, 23, 23, 22, 20, 24, 5, 24, 24,
+ 24, 24, 24, 24, 24, 24, 24, 24
} ;
static yyconst flex_int16_t yy_chk[39] =
{ 0,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
- 3, 3, 3, 25, 24, 21, 3, 4, 4, 4,
- 15, 10, 9, 4, 23, 23, 5, 22, 22, 22,
- 22, 22, 22, 22, 22, 22, 22, 22
+ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+ 26, 25, 23, 17, 11, 10, 5, 24, 24, 24,
+ 24, 24, 24, 24, 24, 24, 24, 24
} ;
/* Table of booleans, true if rule could match eol. */
-static yyconst flex_int32_t yy_rule_can_match_eol[13] =
+static yyconst flex_int32_t yy_rule_can_match_eol[15] =
{ 0,
-0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, };
+0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, };
/* The intent behind this definition is that it'll catch
* any uses of REJECT which flex missed.
@@ -819,13 +819,13 @@ yy_match:
while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
{
yy_current_state = (int) yy_def[yy_current_state];
- if ( yy_current_state >= 23 )
+ if ( yy_current_state >= 25 )
yy_c = yy_meta[(unsigned int) yy_c];
}
yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c];
++yy_cp;
}
- while ( yy_current_state != 22 );
+ while ( yy_current_state != 24 );
yy_cp = yyg->yy_last_accepting_cpos;
yy_current_state = yyg->yy_last_accepting_state;
@@ -915,55 +915,64 @@ case 7:
YY_RULE_SETUP
#line 118 "hex_lexer.l"
{
- return yytext[0];
-}
- YY_BREAK
-case 8:
-YY_RULE_SETUP
-#line 122 "hex_lexer.l"
-{
yylval->integer = atoi(yytext);
return _NUMBER_;
}
YY_BREAK
-case 9:
+case 8:
YY_RULE_SETUP
-#line 128 "hex_lexer.l"
+#line 124 "hex_lexer.l"
{
BEGIN(INITIAL);
return yytext[0];
}
YY_BREAK
+case 9:
+/* rule 9 can match eol */
+YY_RULE_SETUP
+#line 130 "hex_lexer.l"
+// skip whitespaces
+ YY_BREAK
case 10:
-/* rule 10 can match eol */
YY_RULE_SETUP
-#line 135 "hex_lexer.l"
-// skip whitespace
+#line 132 "hex_lexer.l"
+{
+
+ yyerror(yyscanner, lex_env, "invalid character in hex string jump");
+ yyterminate();
+}
YY_BREAK
case 11:
+/* rule 11 can match eol */
YY_RULE_SETUP
#line 138 "hex_lexer.l"
-{
+// skip whitespaces
+ YY_BREAK
+case 12:
+YY_RULE_SETUP
+#line 140 "hex_lexer.l"
+{ // pass valid characters to the parser
- if (yytext[0] >= 32 && yytext[0] < 127)
- {
- return yytext[0];
- }
- else
- {
- yyerror(yyscanner, lex_env, "non-ascii character");
- yyterminate();
- }
+ return yytext[0];
}
YY_BREAK
-case 12:
+case 13:
+YY_RULE_SETUP
+#line 145 "hex_lexer.l"
+{ // reject all other characters
+
+ yyerror(yyscanner, lex_env, "invalid character in hex string");
+ yyterminate();
+}
+ YY_BREAK
+case 14:
YY_RULE_SETUP
#line 151 "hex_lexer.l"
ECHO;
YY_BREAK
-#line 967 "hex_lexer.c"
+#line 976 "hex_lexer.c"
case YY_STATE_EOF(INITIAL):
case YY_STATE_EOF(range):
yyterminate();
@@ -1260,7 +1269,7 @@ static int yy_get_next_buffer (yyscan_t yyscanner)
while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
{
yy_current_state = (int) yy_def[yy_current_state];
- if ( yy_current_state >= 23 )
+ if ( yy_current_state >= 25 )
yy_c = yy_meta[(unsigned int) yy_c];
}
yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c];
@@ -1289,11 +1298,11 @@ static int yy_get_next_buffer (yyscan_t yyscanner)
while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
{
yy_current_state = (int) yy_def[yy_current_state];
- if ( yy_current_state >= 23 )
+ if ( yy_current_state >= 25 )
yy_c = yy_meta[(unsigned int) yy_c];
}
yy_current_state = yy_nxt[yy_base[yy_current_state] + (unsigned int) yy_c];
- yy_is_jam = (yy_current_state == 22);
+ yy_is_jam = (yy_current_state == 24);
(void)yyg;
return yy_is_jam ? 0 : yy_current_state;
@@ -2151,10 +2160,10 @@ void yyerror(
int yr_parse_hex_string(
- const char* hex_string,
- int flags,
- RE** re,
- RE_ERROR* error)
+ const char* hex_string,
+ int flags,
+ RE** re,
+ RE_ERROR* error)
{
yyscan_t yyscanner;
jmp_buf recovery_state;
diff --git a/libyara/hex_lexer.l b/libyara/hex_lexer.l
index 58a1c8b..331542e 100644
--- a/libyara/hex_lexer.l
+++ b/libyara/hex_lexer.l
@@ -111,11 +111,7 @@ hexdigit [a-fA-F0-9]
return yytext[0];
}
-<range>- {
- return yytext[0];
-}
-
-<range>\. {
+<range>\- {
return yytext[0];
}
@@ -131,21 +127,25 @@ hexdigit [a-fA-F0-9]
return yytext[0];
}
+<range>[ \t\r\n] // skip whitespaces
-[ \t\r\n] // skip whitespace
+<range>. {
+ yyerror(yyscanner, lex_env, "invalid character in hex string jump");
+ yyterminate();
+}
-. {
+[ \t\r\n] // skip whitespaces
- if (yytext[0] >= 32 && yytext[0] < 127)
- {
- return yytext[0];
- }
- else
- {
- yyerror(yyscanner, lex_env, "non-ascii character");
- yyterminate();
- }
+[{}()|] { // pass valid characters to the parser
+
+ return yytext[0];
+}
+
+. { // reject all other characters
+
+ yyerror(yyscanner, lex_env, "invalid character in hex string");
+ yyterminate();
}
%%
@@ -198,10 +198,10 @@ void yyerror(
int yr_parse_hex_string(
- const char* hex_string,
- int flags,
- RE** re,
- RE_ERROR* error)
+ const char* hex_string,
+ int flags,
+ RE** re,
+ RE_ERROR* error)
{
yyscan_t yyscanner;
jmp_buf recovery_state;
--
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