From 5f747c7f4bfb7dc97179a1bbe746e083ca38d1e3 Mon Sep 17 00:00:00 2001 From: Geoff Thorpe Date: Thu, 30 Oct 2003 01:07:56 +0000 Subject: When a BN_CTX is used for temporary workspace, the variables are sometimes left in an inconsistent state when they are released for later reuse. This change resets the BIGNUMs when they are released back to the context. --- crypto/bn/bn_ctx.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'crypto/bn') diff --git a/crypto/bn/bn_ctx.c b/crypto/bn/bn_ctx.c index 34cc75cfa9..a0e7915fb9 100644 --- a/crypto/bn/bn_ctx.c +++ b/crypto/bn/bn_ctx.c @@ -167,6 +167,19 @@ void BN_CTX_end(BN_CTX *ctx) ctx->too_many = 0; ctx->depth--; + /* It appears some "scrapbook" uses of BN_CTX result in BIGNUMs being + * left in an inconsistent state when they are released (eg. BN_div). + * These can trip us up when they get reused, so the safest fix is to + * make sure the BIGNUMs are made sane when the context usage is + * releasing them. */ if (ctx->depth < BN_CTX_NUM_POS) +#if 0 ctx->tos = ctx->pos[ctx->depth]; +#else + { + while(ctx->tos > ctx->pos[ctx->depth]) + /* This ensures the BIGNUM is sane(r) for reuse. */ + ctx->bn[--(ctx->tos)].top = 0; + } +#endif } -- cgit v1.2.3