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cxl/mem: Fix potential memory leak

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When submitting a command for userspace, input and output payload bounce
buffers are allocated. For a given command, both input and output
buffers may exist and so when allocation of the input buffer fails, the
output buffer must be freed too.

As far as I can tell, userspace can't easily exploit the leak to OOM a
machine unless the machine was already near OOM state.

Fixes: 583fa5e71cae ("cxl/mem: Add basic IOCTL interface")
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Link: https://lore.kernel.org/r/20210221035846.680145-1-ben.widawsky@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Ben Widawsky 2021-02-20 19:58:46 -08:00 committed by Dan Williams
parent 58294927f4
commit 88ff5d466c
1 changed files with 3 additions and 1 deletions
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4
drivers/cxl/mem.c
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@ -514,8 +514,10 @@ static int handle_mailbox_cmd_from_user(struct cxl_mem *cxlm,
if (cmd->info.size_in) {
mbox_cmd.payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
cmd->info.size_in);
if (IS_ERR(mbox_cmd.payload_in))
if (IS_ERR(mbox_cmd.payload_in)) {
kvfree(mbox_cmd.payload_out);
return PTR_ERR(mbox_cmd.payload_in);
}
}
rc = cxl_mem_mbox_get(cxlm);