diff options
author | Matt Caswell <matt@openssl.org> | 2015-05-19 15:19:30 +0100 |
---|---|---|
committer | Matt Caswell <matt@openssl.org> | 2015-05-22 23:15:02 +0100 |
commit | 7cc18d8158b5fc2676393d99b51c30c135502107 (patch) | |
tree | 45d10d9d5128ff63ade1d546f43e9b138aa9fa6e | |
parent | 2c55a0bc93bf578757ec5c85bdb3abe9cf3f4893 (diff) | |
download | openssl-7cc18d8158b5fc2676393d99b51c30c135502107.tar.gz |
Reject negative shifts for BN_rshift and BN_lshift
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>
-rw-r--r-- | crypto/bn/bn_err.c | 3 | ||||
-rw-r--r-- | crypto/bn/bn_shift.c | 10 | ||||
-rw-r--r-- | doc/crypto/BN_set_bit.pod | 8 | ||||
-rw-r--r-- | include/openssl/bn.h | 3 |
4 files changed, 20 insertions, 4 deletions
diff --git a/crypto/bn/bn_err.c b/crypto/bn/bn_err.c index 13742ff181..1096ec7621 100644 --- a/crypto/bn/bn_err.c +++ b/crypto/bn/bn_err.c @@ -98,6 +98,7 @@ 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"}, @@ -113,6 +114,7 @@ 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_SET_WORDS), "bn_set_words"}, {ERR_FUNC(BN_F_BN_USUB), "BN_usub"}, {0, NULL} @@ -131,6 +133,7 @@ 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"}, diff --git a/crypto/bn/bn_shift.c b/crypto/bn/bn_shift.c index 1b38bd861a..4e43a60b22 100644 --- a/crypto/bn/bn_shift.c +++ b/crypto/bn/bn_shift.c @@ -136,6 +136,11 @@ 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) @@ -170,6 +175,11 @@ 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; diff --git a/doc/crypto/BN_set_bit.pod b/doc/crypto/BN_set_bit.pod index b7c47b9b01..a32cca2cee 100644 --- a/doc/crypto/BN_set_bit.pod +++ b/doc/crypto/BN_set_bit.pod @@ -37,12 +37,12 @@ BN_mask_bits() truncates B<a> to an B<n> bit number shorter than B<n> bits. BN_lshift() shifts B<a> left by B<n> bits and places the result in -B<r> (C<r=a*2^n>). BN_lshift1() shifts B<a> left by one and places -the result in B<r> (C<r=2*a>). +B<r> (C<r=a*2^n>). Note that B<n> must be non-negative. BN_lshift1() shifts +B<a> left by one and places the result in B<r> (C<r=2*a>). BN_rshift() shifts B<a> right by B<n> bits and places the result in -B<r> (C<r=a/2^n>). BN_rshift1() shifts B<a> right by one and places -the result in B<r> (C<r=a/2>). +B<r> (C<r=a/2^n>). Note that B<n> must be non-negative. BN_rshift1() shifts +B<a> right by one and places the result in B<r> (C<r=a/2>). For the shift functions, B<r> and B<a> may be the same variable. diff --git a/include/openssl/bn.h b/include/openssl/bn.h index 9c53aaf05a..44f17374f2 100644 --- a/include/openssl/bn.h +++ b/include/openssl/bn.h @@ -711,6 +711,7 @@ 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 @@ -726,6 +727,7 @@ 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_SET_WORDS 144 # define BN_F_BN_USUB 115 @@ -741,6 +743,7 @@ 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 |