generic-library/openssl
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Reject negative shifts for BN_rshift and BN_lshift

Browse Source 
The functions BN_rshift and BN_lshift shift their arguments to the right or
left by a specified number of bits. Unpredicatable results (including
crashes) can occur if a negative number is supplied for the shift value.

Thanks to Mateusz Kocielski (LogicalTrust), Marek Kroemeke and Filip Palian
for discovering and reporting this issue.

Reviewed-by: Kurt Roeckx <kurt@openssl.org>
(cherry picked from commit 7cc18d8158)

Conflicts:
	crypto/bn/bn.h
	crypto/bn/bn_err.c
This commit is contained in:
Matt Caswell
2015-05-19 15:19:30 +01:00
parent 254c01ed54
commit 1a9499cf23
4 changed files with 20 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
crypto/bn/bn.h
View File

@@ -893,6 +893,7 @@ void ERR_load_BN_strings(void);
# define BN_F_BN_GF2M_MOD_SOLVE_QUAD_ARR 135
# define BN_F_BN_GF2M_MOD_SQR 136
# define BN_F_BN_GF2M_MOD_SQRT 137
# define BN_F_BN_LSHIFT 145
# define BN_F_BN_MOD_EXP2_MONT 118
# define BN_F_BN_MOD_EXP_MONT 109
# define BN_F_BN_MOD_EXP_MONT_CONSTTIME 124
@@ -908,6 +909,7 @@ void ERR_load_BN_strings(void);
# define BN_F_BN_NEW 113
# define BN_F_BN_RAND 114
# define BN_F_BN_RAND_RANGE 122
# define BN_F_BN_RSHIFT 146
# define BN_F_BN_USUB 115
/* Reason codes. */
@@ -921,6 +923,7 @@ void ERR_load_BN_strings(void);
# define BN_R_INPUT_NOT_REDUCED 110
# define BN_R_INVALID_LENGTH 106
# define BN_R_INVALID_RANGE 115
# define BN_R_INVALID_SHIFT 119
# define BN_R_NOT_A_SQUARE 111
# define BN_R_NOT_INITIALIZED 107
# define BN_R_NO_INVERSE 108

3
crypto/bn/bn_err.c
View File

@@ -94,6 +94,7 @@ static ERR_STRING_DATA BN_str_functs[] = {
{ERR_FUNC(BN_F_BN_GF2M_MOD_SOLVE_QUAD_ARR), "BN_GF2m_mod_solve_quad_arr"},
{ERR_FUNC(BN_F_BN_GF2M_MOD_SQR), "BN_GF2m_mod_sqr"},
{ERR_FUNC(BN_F_BN_GF2M_MOD_SQRT), "BN_GF2m_mod_sqrt"},
{ERR_FUNC(BN_F_BN_LSHIFT), "BN_lshift"},
{ERR_FUNC(BN_F_BN_MOD_EXP2_MONT), "BN_mod_exp2_mont"},
{ERR_FUNC(BN_F_BN_MOD_EXP_MONT), "BN_mod_exp_mont"},
{ERR_FUNC(BN_F_BN_MOD_EXP_MONT_CONSTTIME), "BN_mod_exp_mont_consttime"},
@@ -109,6 +110,7 @@ static ERR_STRING_DATA BN_str_functs[] = {
{ERR_FUNC(BN_F_BN_NEW), "BN_new"},
{ERR_FUNC(BN_F_BN_RAND), "BN_rand"},
{ERR_FUNC(BN_F_BN_RAND_RANGE), "BN_rand_range"},
{ERR_FUNC(BN_F_BN_RSHIFT), "BN_rshift"},
{ERR_FUNC(BN_F_BN_USUB), "BN_usub"},
{0, NULL}
};
@@ -125,6 +127,7 @@ static ERR_STRING_DATA BN_str_reasons[] = {
{ERR_REASON(BN_R_INPUT_NOT_REDUCED), "input not reduced"},
{ERR_REASON(BN_R_INVALID_LENGTH), "invalid length"},
{ERR_REASON(BN_R_INVALID_RANGE), "invalid range"},
{ERR_REASON(BN_R_INVALID_SHIFT), "invalid shift"},
{ERR_REASON(BN_R_NOT_A_SQUARE), "not a square"},
{ERR_REASON(BN_R_NOT_INITIALIZED), "not initialized"},
{ERR_REASON(BN_R_NO_INVERSE), "no inverse"},

10
crypto/bn/bn_shift.c
View File

@@ -137,6 +137,11 @@ int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
bn_check_top(r);
bn_check_top(a);
if (n < 0) {
BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);
return 0;
}
r->neg = a->neg;
nw = n / BN_BITS2;
if (bn_wexpand(r, a->top + nw + 1) == NULL)
@@ -174,6 +179,11 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
bn_check_top(r);
bn_check_top(a);
if (n < 0) {
BNerr(BN_F_BN_RSHIFT, BN_R_INVALID_SHIFT);
return 0;
}
nw = n / BN_BITS2;
rb = n % BN_BITS2;
lb = BN_BITS2 - rb;