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| author | jsing <> | 2024-04-15 14:35:25 +0000 |
|---|---|---|
| committer | jsing <> | 2024-04-15 14:35:25 +0000 |
| commit | d2daaa3702c2e527e918b7aa9f6c6183ca882b53 (patch) | |
| tree | 7c40fc922bc215b7006125221e65b5d3a04adbe4 /src/lib | |
| parent | f7646eb021595fb6f85c38b99e043277fa2436bc (diff) | |
| download | openbsd-d2daaa3702c2e527e918b7aa9f6c6183ca882b53.tar.gz openbsd-d2daaa3702c2e527e918b7aa9f6c6183ca882b53.tar.bz2 openbsd-d2daaa3702c2e527e918b7aa9f6c6183ca882b53.zip | |
Prevent negative zero from being created via BN bit functions.
Both BN_clear_bit() and BN_mask_bits() can create zero values - in both
cases ensure that the negative sign is correctly handled if the value
becomes zero.
Thanks to Guido Vranken for providing a reproducer.
Fixes oss-fuzz #67901
ok tb@
Diffstat (limited to 'src/lib')
| -rw-r--r-- | src/lib/libcrypto/bn/bn_lib.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/lib/libcrypto/bn/bn_lib.c b/src/lib/libcrypto/bn/bn_lib.c index c0c0ac876f..b59e65a1e1 100644 --- a/src/lib/libcrypto/bn/bn_lib.c +++ b/src/lib/libcrypto/bn/bn_lib.c | |||
| @@ -1,4 +1,4 @@ | |||
| 1 | /* $OpenBSD: bn_lib.c,v 1.90 2023/07/28 10:35:14 tb Exp $ */ | 1 | /* $OpenBSD: bn_lib.c,v 1.91 2024/04/15 14:35:25 jsing Exp $ */ |
| 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | 2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
| 3 | * All rights reserved. | 3 | * All rights reserved. |
| 4 | * | 4 | * |
| @@ -438,6 +438,9 @@ BN_clear_bit(BIGNUM *a, int n) | |||
| 438 | 438 | ||
| 439 | a->d[i] &= (~(((BN_ULONG)1) << j)); | 439 | a->d[i] &= (~(((BN_ULONG)1) << j)); |
| 440 | bn_correct_top(a); | 440 | bn_correct_top(a); |
| 441 | |||
| 442 | BN_set_negative(a, a->neg); | ||
| 443 | |||
| 441 | return (1); | 444 | return (1); |
| 442 | } | 445 | } |
| 443 | LCRYPTO_ALIAS(BN_clear_bit); | 446 | LCRYPTO_ALIAS(BN_clear_bit); |
| @@ -476,6 +479,9 @@ BN_mask_bits(BIGNUM *a, int n) | |||
| 476 | a->d[w] &= ~(BN_MASK2 << b); | 479 | a->d[w] &= ~(BN_MASK2 << b); |
| 477 | } | 480 | } |
| 478 | bn_correct_top(a); | 481 | bn_correct_top(a); |
| 482 | |||
| 483 | BN_set_negative(a, a->neg); | ||
| 484 | |||
| 479 | return (1); | 485 | return (1); |
| 480 | } | 486 | } |
| 481 | LCRYPTO_ALIAS(BN_mask_bits); | 487 | LCRYPTO_ALIAS(BN_mask_bits); |