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| author | Dan Williams <dan.j.williams@intel.com> | 2017-09-01 01:41:55 +0300 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2017-09-01 01:41:55 +0300 |
| commit | 58738c495e15badd2015e19ff41f1f1ed55200bc (patch) | |
| tree | c10882907b7c9a25db21a696af8d0298346a1b90 /drivers/nvdimm/bus.c | |
| parent | 5deb67f77a266010e2c10fb124b7516d0d258ce8 (diff) | |
| download | linux-58738c495e15badd2015e19ff41f1f1ed55200bc.tar.xz | |
libnvdimm: fix integer overflow static analysis warning
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>
Diffstat (limited to 'drivers/nvdimm/bus.c')
| -rw-r--r-- | drivers/nvdimm/bus.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index a18c2914f4b6..66586ce23f1b 100644 --- a/drivers/nvdimm/bus.c +++ b/drivers/nvdimm/bus.c @@ -911,19 +911,20 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 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); - unsigned int func = cmd; - void __user *p = (void __user *) arg; struct device *dev = &nvdimm_bus->dev; - struct nd_cmd_pkg pkg; + void __user *p = (void __user *) arg; const char *cmd_name, *dimm_name; + u32 in_len = 0, out_len = 0; + unsigned int func = cmd; unsigned long cmd_mask; - void *buf; + struct nd_cmd_pkg pkg; int rc, i, cmd_rc; + u64 buf_len = 0; + void *buf; if (nvdimm) { desc = nd_cmd_dimm_desc(cmd); @@ -983,7 +984,7 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, if (cmd == ND_CMD_CALL) { func = pkg.nd_command; - 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); @@ -1013,9 +1014,9 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm, 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; |