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Add safeguards against string overflows

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Use snprintf instead of other unsafe functions. That way it is possible
to limit the size of the buffer and to ensure that it never overflows.

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>
This commit is contained in:
Antonio Niño Díaz
2018-01-08 00:14:44 +00:00
parent 0e0e12a769
commit 2a97535e75
3 changed files with 49 additions and 24 deletions
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25
src/asm/asmy.y
View File

@@ -1312,26 +1312,37 @@ const : T_ID { $$ = sym_GetConstantValue($1); }
string : T_STRING
{
strcpy($$, $1);
if (snprintf($$, MAXSTRLEN + 1, "%s", $1) > MAXSTRLEN)
warning("String is too long '%s'", $1);
}
| T_OP_STRSUB '(' string comma uconst comma uconst ')'
{
strncpy($$, $3 + $5 - 1, $7);
$$[$7] = 0;
uint32_t len = $7;
if (len > MAXSTRLEN) {
warning("STRSUB: Length too big: %u", len);
len = MAXSTRLEN;
}
if (snprintf($$, len + 1, "%s", $3 + $5 - 1) > MAXSTRLEN)
warning("STRSUB: String too long '%s'", $$);
}
| T_OP_STRCAT '(' string comma string ')'
{
strcpy($$, $3);
strcat($$, $5);
if (snprintf($$, MAXSTRLEN + 1, "%s%s", $3, $5) > MAXSTRLEN)
warning("STRCAT: String too long '%s%s'", $3, $5);
}
| T_OP_STRUPR '(' string ')'
{
strcpy($$, $3);
if (snprintf($$, MAXSTRLEN + 1, "%s", $3) > MAXSTRLEN)
warning("STRUPR: String too long '%s'", $3);
upperstring($$);
}
| T_OP_STRLWR '(' string ')'
{
strcpy($$, $3);
if (snprintf($$, MAXSTRLEN + 1, "%s", $3) > MAXSTRLEN)
warning("STRUPR: String too long '%s'", $3);
lowerstring($$);
}
;

4
src/asm/fstack.c
View File

@@ -347,7 +347,7 @@ void fstk_RunMacroArg(int32_t s)
pushcontext();
nCurrentStatus = STAT_isMacroArg;
sprintf(tzCurrentFileName, "%c", (uint8_t)s);
snprintf(tzCurrentFileName, _MAX_PATH + 1, "%c", (uint8_t)s);
CurrentFlexHandle = yy_scan_bytes(sym, strlen(sym));
yy_switch_to_buffer(CurrentFlexHandle);
}
@@ -410,7 +410,7 @@ void fstk_Init(char *s)
nMacroCount = 0;
nCurrentStatus = STAT_isInclude;
strcpy(tzCurrentFileName, tzFileName);
snprintf(tzCurrentFileName, _MAX_PATH + 1, "%s", tzFileName);
CurrentFlexHandle = yy_create_buffer(pCurrentFile);
yy_switch_to_buffer(CurrentFlexHandle);
nLineNo = 1;

44
src/asm/symbol.c
View File

@@ -40,7 +40,7 @@ static char SavedTIMESTAMP_ISO8601_LOCAL[256];
static char SavedTIMESTAMP_ISO8601_UTC[256];
static char SavedDAY[3];
static char SavedMONTH[3];
static char SavedYEAR[5];
static char SavedYEAR[20];
static char SavedHOUR[3];
static char SavedMINUTE[3];
static char SavedSECOND[3];
@@ -122,7 +122,9 @@ struct sSymbol *createsymbol(char *s)
return NULL;
}
strcpy((*ppsym)->tzName, s);
if (snprintf((*ppsym)->tzName, MAXSYMLEN + 1, "%s", s) > MAXSYMLEN)
warning("Symbol name is too long: '%s'", s);
(*ppsym)->nValue = 0;
(*ppsym)->nType = 0;
(*ppsym)->pScope = NULL;
@@ -130,7 +132,13 @@ struct sSymbol *createsymbol(char *s)
(*ppsym)->pMacro = NULL;
(*ppsym)->pSection = NULL;
(*ppsym)->Callback = NULL;
strcpy((*ppsym)->tzFileName, tzCurrentFileName);
if (snprintf((*ppsym)->tzFileName, _MAX_PATH + 1, "%s",
tzCurrentFileName) > _MAX_PATH) {
fatalerror("%s: File name is too long: '%s'", __func__,
tzCurrentFileName);
}
(*ppsym)->nFileLine = fstk_GetLine();
return *ppsym;
}
@@ -509,7 +517,7 @@ void sym_SetMacroArgID(uint32_t nMacroCount)
{
char s[256];
sprintf(s, "_%u", nMacroCount);
snprintf(s, sizeof(s), "_%u", nMacroCount);
newmacroargs[MAXMACROARGS] = strdup(s);
}
@@ -560,7 +568,7 @@ void sym_AddEqu(char *tzSym, int32_t value)
*
* If the desired symbol is a string it needs to be passed to this function with
* quotes inside the string, like sym_AddString("name", "\"test\"), or the
* assembler won't be able to use it with DB and similar. This is equivalent as
* assembler won't be able to use it with DB and similar. This is equivalent to
* ``` name EQUS "\"test\"" ```
*
* If the desired symbol is a register or a number, just the terminator quotes
@@ -965,16 +973,22 @@ void sym_Init(void)
* The '?' have to be escaped or they will be treated as
* trigraphs...
*/
strcpy(SavedTIME, "\"\?\?:\?\?:\?\?\"");
strcpy(SavedDATE, "\"\?\? \?\?\? \?\?\?\?\"");
strcpy(SavedTIMESTAMP_ISO8601_LOCAL, "\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?+\?\?\?\?\"");
strcpy(SavedTIMESTAMP_ISO8601_UTC, "\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?Z\"");
strcpy(SavedDAY, "1");
strcpy(SavedMONTH, "1");
strcpy(SavedYEAR, "1900");
strcpy(SavedHOUR, "0");
strcpy(SavedMINUTE, "0");
strcpy(SavedSECOND, "0");
snprintf(SavedTIME, sizeof(SavedTIME),
"\"\?\?:\?\?:\?\?\"");
snprintf(SavedDATE, sizeof(SavedDATE),
"\"\?\? \?\?\? \?\?\?\?\"");
snprintf(SavedTIMESTAMP_ISO8601_LOCAL,
sizeof(SavedTIMESTAMP_ISO8601_LOCAL),
"\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?+\?\?\?\?\"");
snprintf(SavedTIMESTAMP_ISO8601_UTC,
sizeof(SavedTIMESTAMP_ISO8601_UTC),
"\"\?\?\?\?-\?\?-\?\?T\?\?:\?\?:\?\?Z\"");
snprintf(SavedDAY, sizeof(SavedDAY), "1");
snprintf(SavedMONTH, sizeof(SavedMONTH), "1");
snprintf(SavedYEAR, sizeof(SavedYEAR), "1900");
snprintf(SavedHOUR, sizeof(SavedHOUR), "0");
snprintf(SavedMINUTE, sizeof(SavedMINUTE), "0");
snprintf(SavedSECOND, sizeof(SavedSECOND), "0");
}
sym_AddString("__TIME__", SavedTIME);