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parser: Quiet valgrind false positive

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strlen() assumes that it can read an entire word but when a char array
does not end on a word boundary, it reads past the end of the array.
This results in the following valgrind warning:

 Invalid read of size 4
    at 0x40A162: yylex() (parser_lex.l:277)
    by 0x40FA14: yyparse() (parser_yacc.c:1487)
    by 0x40C5B9: process_profile(int, char const*) (parser_main.c:1003)
    by 0x404074: main (parser_main.c:1340)
  Address 0x578d870 is 16 bytes inside a block of size 18 alloc'd
    at 0x4C2A420: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
    by 0x53E31C9: strdup (strdup.c:42)
    by 0x40A145: yylex() (parser_lex.l:276)
    by 0x40FA14: yyparse() (parser_yacc.c:1487)
    by 0x40C5B9: process_profile(int, char const*) (parser_main.c:1003)
    by 0x404074: main (parser_main.c:1340)

This patch quiets the warning by not using strlen(). This can be done
because yyleng already contains the length of string.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Steve Beattie <steve@nxnw.org>
This commit is contained in:
Tyler Hicks 2014-02-05 13:39:24 -05:00
parent 5df1ac3610
commit 2001fb6f81
1 changed files with 1 additions and 2 deletions
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3
parser/parser_lex.l
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@ -273,8 +273,7 @@ LT_EQUAL <=
<INCLUDE>{
(\<([^\> \t\n]+)\>|\"([^\" \t\n]+)\") { /* <filename> */
char *filename = strdup(yytext);
filename[strlen(filename) - 1] = '\0';
char *filename = strndup(yytext, yyleng - 1);
include_filename(filename + 1, *filename == '<');
free(filename);
yy_pop_state();