4.9-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams dan.j.williams@intel.com
commit 58738c495e15badd2015e19ff41f1f1ed55200bc upstream.
Dan reports: The patch 62232e45f4a2: "libnvdimm: control (ioctl) messages for nvdimm_bus and nvdimm devices" from Jun 8, 2015, leads to the following static checker warning:
drivers/nvdimm/bus.c:1018 __nd_ioctl() warn: integer overflows 'buf_len'
From a casual review, this seems like it might be a real bug. On the first iteration we load some data into in_env[]. On the second iteration we read a use controlled "in_size" from nd_cmd_in_size(). It can go up to UINT_MAX - 1. A high number means we will fill the whole in_env[] buffer. But we potentially keep looping and adding more to in_len so now it can be any value.
It simple enough to change, but it feels weird that we keep looping even though in_env is totally full. Shouldn't we just return an error if we don't have space for desc->in_num.
We keep looping because the size of the total input is allowed to be bigger than the 'envelope' which is a subset of the payload that tells us how much data to expect. For safety explicitly check that buf_len does not overflow which is what the checker flagged.
Cc: stable@vger.kernel.org Fixes: 62232e45f4a2: "libnvdimm: control (ioctl) messages for nvdimm_bus..." Reported-by: Dan Carpenter dan.carpenter@oracle.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/nvdimm/bus.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -812,16 +812,17 @@ static int __nd_ioctl(struct nvdimm_bus int read_only, unsigned int ioctl_cmd, unsigned long arg) { struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc; - size_t buf_len = 0, in_len = 0, out_len = 0; static char out_env[ND_CMD_MAX_ENVELOPE]; static char in_env[ND_CMD_MAX_ENVELOPE]; const struct nd_cmd_desc *desc = NULL; unsigned int cmd = _IOC_NR(ioctl_cmd); void __user *p = (void __user *) arg; struct device *dev = &nvdimm_bus->dev; - struct nd_cmd_pkg pkg; const char *cmd_name, *dimm_name; + u32 in_len = 0, out_len = 0; unsigned long cmd_mask; + struct nd_cmd_pkg pkg; + u64 buf_len = 0; void *buf; int rc, i;
@@ -882,7 +883,7 @@ static int __nd_ioctl(struct nvdimm_bus }
if (cmd == ND_CMD_CALL) { - dev_dbg(dev, "%s:%s, idx: %llu, in: %zu, out: %zu, len %zu\n", + dev_dbg(dev, "%s:%s, idx: %llu, in: %u, out: %u, len %llu\n", __func__, dimm_name, pkg.nd_command, in_len, out_len, buf_len);
@@ -912,9 +913,9 @@ static int __nd_ioctl(struct nvdimm_bus out_len += out_size; }
- buf_len = out_len + in_len; + buf_len = (u64) out_len + (u64) in_len; if (buf_len > ND_IOCTL_MAX_BUFLEN) { - dev_dbg(dev, "%s:%s cmd: %s buf_len: %zu > %d\n", __func__, + dev_dbg(dev, "%s:%s cmd: %s buf_len: %llu > %d\n", __func__, dimm_name, cmd_name, buf_len, ND_IOCTL_MAX_BUFLEN); return -EINVAL;