From 29c838cdc96c4d117f00c75bbcb941e1be9590fb Mon Sep 17 00:00:00 2001 From: Peter Lieven Date: Fri, 26 Jun 2015 13:14:01 +0200 Subject: block/nfs: limit maximum readahead size to 1MB a malicious caller could otherwise specify a very large value via the URI and force libnfs to allocate a large amount of memory for the readahead buffer. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Lieven Message-id: 1435317241-25585-1-git-send-email-pl@kamp.de Signed-off-by: Stefan Hajnoczi --- block/nfs.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'block/nfs.c') diff --git a/block/nfs.c b/block/nfs.c index ca9e24efe5..c026ff6883 100644 --- a/block/nfs.c +++ b/block/nfs.c @@ -35,6 +35,8 @@ #include "sysemu/sysemu.h" #include +#define QEMU_NFS_MAX_READAHEAD_SIZE 1048576 + typedef struct NFSClient { struct nfs_context *context; struct nfsfh *fh; @@ -327,6 +329,11 @@ static int64_t nfs_client_open(NFSClient *client, const char *filename, nfs_set_tcp_syncnt(client->context, val); #ifdef LIBNFS_FEATURE_READAHEAD } else if (!strcmp(qp->p[i].name, "readahead")) { + if (val > QEMU_NFS_MAX_READAHEAD_SIZE) { + error_report("NFS Warning: Truncating NFS readahead" + " size to %d", QEMU_NFS_MAX_READAHEAD_SIZE); + val = QEMU_NFS_MAX_READAHEAD_SIZE; + } nfs_set_readahead(client->context, val); #endif } else { -- cgit v1.2.1