From 52ad259eaac0454c1ac7123e7148cf8d6e6f5301 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Adeodato=20Sim=C3=B3?= Date: Tue, 13 Nov 2018 03:28:53 -0300 Subject: [PATCH 1/2] net/9p: include trans_common.h to fix missing prototype warning. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This silences -Wmissing-prototypes when defining p9_release_pages. Link: http://lkml.kernel.org/r/b1c4df8f21689b10d451c28fe38e860722d20e71.1542089696.git.dato@net.com.org.es Signed-off-by: Adeodato Simó Signed-off-by: Dominique Martinet --- net/9p/trans_common.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/9p/trans_common.c b/net/9p/trans_common.c index b718db2085b2..3dff68f05fb9 100644 --- a/net/9p/trans_common.c +++ b/net/9p/trans_common.c @@ -14,6 +14,7 @@ #include #include +#include "trans_common.h" /** * p9_release_pages - Release pages after the transaction. From 574d356b7a02c7e1b01a1d9cba8a26b3c2888f45 Mon Sep 17 00:00:00 2001 From: Dominique Martinet Date: Mon, 5 Nov 2018 09:52:48 +0100 Subject: [PATCH 2/2] 9p/net: put a lower bound on msize If the requested msize is too small (either from command line argument or from the server version reply), we won't get any work done. If it's *really* too small, nothing will work, and this got caught by syzbot recently (on a new kmem_cache_create_usercopy() call) Just set a minimum msize to 4k in both code paths, until someone complains they have a use-case for a smaller msize. We need to check in both mount option and server reply individually because the msize for the first version request would be unchecked with just a global check on clnt->msize. Link: http://lkml.kernel.org/r/1541407968-31350-1-git-send-email-asmadeus@codewreck.org Reported-by: syzbot+0c1d61e4db7db94102ca@syzkaller.appspotmail.com Signed-off-by: Dominique Martinet Cc: Eric Van Hensbergen Cc: Latchesar Ionkov Cc: stable@vger.kernel.org --- net/9p/client.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/net/9p/client.c b/net/9p/client.c index 2c9a17b9b46b..357214a51f13 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -181,6 +181,12 @@ static int parse_opts(char *opts, struct p9_client *clnt) ret = r; continue; } + if (option < 4096) { + p9_debug(P9_DEBUG_ERROR, + "msize should be at least 4k\n"); + ret = -EINVAL; + continue; + } clnt->msize = option; break; case Opt_trans: @@ -983,10 +989,18 @@ static int p9_client_version(struct p9_client *c) else if (!strncmp(version, "9P2000", 6)) c->proto_version = p9_proto_legacy; else { + p9_debug(P9_DEBUG_ERROR, + "server returned an unknown version: %s\n", version); err = -EREMOTEIO; goto error; } + if (msize < 4096) { + p9_debug(P9_DEBUG_ERROR, + "server returned a msize < 4096: %d\n", msize); + err = -EREMOTEIO; + goto error; + } if (msize < c->msize) c->msize = msize; @@ -1043,6 +1057,13 @@ struct p9_client *p9_client_create(const char *dev_name, char *options) if (clnt->msize > clnt->trans_mod->maxsize) clnt->msize = clnt->trans_mod->maxsize; + if (clnt->msize < 4096) { + p9_debug(P9_DEBUG_ERROR, + "Please specify a msize of at least 4k\n"); + err = -EINVAL; + goto free_client; + } + err = p9_client_version(clnt); if (err) goto close_trans;