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authorSimon Derr <simon.derr@bull.net>2012-08-10 15:52:06 +0200
committerEric Van Hensbergen <ericvh@gmail.com>2012-09-06 13:54:55 -0500
commit43def35c1030d91a7414936c7c1b416828b20afb (patch)
tree58e6a3f765f7319c91abf45978c34c60f188b9ee /net/9p/client.c
parentba413ab2ccc49e6aa1ebc3523a75635b5e4a0494 (diff)
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net/9p: Check errno validity
While working on a modified server I had the Linux clients crash a few times. This lead me to find this: Some error codes are directly extracted from the server replies. A malformed server reply could contain an invalid error code, with a very large value. If this value is then passed to ERR_PTR() it will not be properly detected as an error code by IS_ERR() and as a result the kernel will dereference an invalid pointer. This patch tries to avoid this. Signed-off-by: Simon Derr <simon.derr@bull.net> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Diffstat (limited to 'net/9p/client.c')
-rw-r--r--net/9p/client.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/net/9p/client.c b/net/9p/client.c
index 8260f132b32e..34d417670935 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -76,6 +76,20 @@ inline int p9_is_proto_dotu(struct p9_client *clnt)
}
EXPORT_SYMBOL(p9_is_proto_dotu);
+/*
+ * Some error codes are taken directly from the server replies,
+ * make sure they are valid.
+ */
+static int safe_errno(int err)
+{
+ if ((err > 0) || (err < -MAX_ERRNO)) {
+ p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
+ return -EPROTO;
+ }
+ return err;
+}
+
+
/* Interpret mount option for protocol version */
static int get_protocol_version(char *s)
{
@@ -782,7 +796,7 @@ again:
return req;
reterr:
p9_free_req(c, req);
- return ERR_PTR(err);
+ return ERR_PTR(safe_errno(err));
}
/**
@@ -865,7 +879,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
return req;
reterr:
p9_free_req(c, req);
- return ERR_PTR(err);
+ return ERR_PTR(safe_errno(err));
}
static struct p9_fid *p9_fid_create(struct p9_client *clnt)