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Add overflow checks to parse_number/parse_hex/parse_oct 

Test the next arithmetic operation to safely determine if adding the
next digit in the passed property string will overflow

Also, noted a bug in the parse_hex code.  When parsing non-digit
characters (i.e. a-f and A-F), we do a tolower conversion (which is
fine), and then subtract 'a' to get the hex value from the ascii (which
is definately wrong).  We should subtract 'W' to convert tolower
converted hex digits in the range a-f to their hex value counterparts

Add tests to test_property_parse_error to ensure overflow checks work

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
(Merged from https://github.com/openssl/openssl/pull/22874)
This commit is contained in:
Neil Horman 2023-11-28 13:54:37 -05:00
parent 504ff2a4ef
commit 986c48c4eb
2 changed files with 47 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
crypto/property/property_parse.c
View File

@ -97,9 +97,18 @@ static int parse_number(const char *t[], OSSL_PROPERTY_DEFINITION *res)
const char *s = *t;
int64_t v = 0;
if (!ossl_isdigit(*s))
return 0;
do {
if (!ossl_isdigit(*s)) {
ERR_raise_data(ERR_LIB_PROP, PROP_R_NOT_A_DECIMAL_DIGIT,
"HERE-->%s", *t);
return 0;
}
/* overflow check */
if (v > ((INT64_MAX - (*s - '0')) / 10)) {
ERR_raise_data(ERR_LIB_PROP, PROP_R_PARSE_FAILED,
"Property %s overflows", *t);
return 0;
}
v = v * 10 + (*s++ - '0');
} while (ossl_isdigit(*s));
if (!ossl_isspace(*s) && *s != '\0' && *s != ',') {
@ -117,15 +126,27 @@ static int parse_hex(const char *t[], OSSL_PROPERTY_DEFINITION *res)
{
const char *s = *t;
int64_t v = 0;
int sval;
if (!ossl_isxdigit(*s))
return 0;
do {
if (ossl_isdigit(*s)) {
sval = *s - '0';
} else if (ossl_isxdigit(*s)) {
sval = ossl_tolower(*s) - 'a' + 10;
} else {
ERR_raise_data(ERR_LIB_PROP, PROP_R_NOT_AN_HEXADECIMAL_DIGIT,
"%s", *t);
return 0;
}
if (v > ((INT64_MAX - sval) / 16)) {
ERR_raise_data(ERR_LIB_PROP, PROP_R_PARSE_FAILED,
"Property %s overflows", *t);
return 0;
}
v <<= 4;
if (ossl_isdigit(*s))
v += *s - '0';
else
v += ossl_tolower(*s) - 'a';
v += sval;
} while (ossl_isxdigit(*++s));
if (!ossl_isspace(*s) && *s != '\0' && *s != ',') {
ERR_raise_data(ERR_LIB_PROP, PROP_R_NOT_AN_HEXADECIMAL_DIGIT,
@ -143,9 +164,18 @@ static int parse_oct(const char *t[], OSSL_PROPERTY_DEFINITION *res)
const char *s = *t;
int64_t v = 0;
if (*s == '9' || *s == '8' || !ossl_isdigit(*s))
return 0;
do {
if (*s == '9' || *s == '8' || !ossl_isdigit(*s)) {
ERR_raise_data(ERR_LIB_PROP, PROP_R_NOT_AN_OCTAL_DIGIT,
"HERE-->%s", *t);
return 0;
}
if (v > ((INT64_MAX - (*s - '0')) / 8)) {
ERR_raise_data(ERR_LIB_PROP, PROP_R_PARSE_FAILED,
"Property %s overflows", *t);
return 0;
}
v = (v << 3) + (*s - '0');
} while (ossl_isdigit(*++s) && *s != '9' && *s != '8');
if (!ossl_isspace(*s) && *s != '\0' && *s != ',') {

7
test/property_test.c
View File

@ -136,6 +136,10 @@ static const struct {
{ "n=0x3", "n=3", 1 },
{ "n=0x3", "n=-3", -1 },
{ "n=0x33", "n=51", 1 },
{ "n=0x123456789abcdef", "n=0x123456789abcdef", 1 },
{ "n=0x7fffffffffffffff", "n=0x7fffffffffffffff", 1 }, /* INT64_MAX */
{ "n=9223372036854775807", "n=9223372036854775807", 1 }, /* INT64_MAX */
{ "n=0777777777777777777777", "n=0777777777777777777777", 1 }, /* INT64_MAX */
{ "n=033", "n=27", 1 },
{ "n=0", "n=00", 1 },
{ "n=0x0", "n=0", 1 },
@ -198,6 +202,9 @@ static const struct {
{ 1, "a=2, n=012345678" }, /* Bad octal digit */
{ 0, "n=0x28FG, a=3" }, /* Bad hex digit */
{ 0, "n=145d, a=2" }, /* Bad decimal digit */
{ 0, "n=0x8000000000000000, a=3" }, /* Hex overflow */
{ 0, "n=922337203000000000d, a=2" }, /* Decimal overflow */
{ 0, "a=2, n=1000000000000000000000" }, /* Octal overflow */
{ 1, "@='hello'" }, /* Invalid name */
{ 1, "n0123456789012345678901234567890123456789"
"0123456789012345678901234567890123456789"