From 0a4805bf943be5b573b0560ecfcc88ff9999fd95 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Tue, 29 Sep 2015 01:24:36 +0100 Subject: [PATCH] [peerdist] Avoid NULL pointer dereference for plaintext blocks Avoid accidentally dereferencing a NULL cipher context pointer for plaintext blocks (which are usually messages with a block length of zero, indicating a missing block). Signed-off-by: Michael Brown --- src/net/peerblk.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/src/net/peerblk.c b/src/net/peerblk.c index fd7ea089..9fd52b73 100644 --- a/src/net/peerblk.c +++ b/src/net/peerblk.c @@ -700,17 +700,20 @@ static int peerblk_parse_header ( struct peerdist_block *peerblk ) { return -EPROTO; } - /* Allocate cipher context. Freeing the cipher context (on - * error or otherwise) is handled by peerblk_reset(). + /* Allocate cipher context, if applicable. Freeing the cipher + * context (on error or otherwise) is handled by peerblk_reset(). */ peerblk->cipher = cipher; assert ( peerblk->cipherctx == NULL ); - peerblk->cipherctx = malloc ( cipher->ctxsize ); - if ( ! peerblk->cipherctx ) - return -ENOMEM; + if ( cipher ) { + peerblk->cipherctx = malloc ( cipher->ctxsize ); + if ( ! peerblk->cipherctx ) + return -ENOMEM; + } - /* Initialise cipher */ - if ( ( rc = cipher_setkey ( cipher, peerblk->cipherctx, peerblk->secret, + /* Initialise cipher, if applicable */ + if ( cipher && + ( rc = cipher_setkey ( cipher, peerblk->cipherctx, peerblk->secret, keylen ) ) != 0 ) { DBGC ( peerblk, "PEERBLK %p %d.%d could not set key: %s\n", peerblk, peerblk->segment, peerblk->block,