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a1aa5390cc
In of_modalias(), we can get passed the str and len parameters which would cause a kernel oops in vsnprintf() since it only allows passing a NULL ptr when the length is also 0. Also, we need to filter out the negative values of the len parameter as these will result in a really huge buffer since snprintf() takes size_t parameter while ours is ssize_t... Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool. Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1d211023-3923-685b-20f0-f3f90ea56e1f@omp.ru Signed-off-by: Rob Herring <robh@kernel.org>
83 lines
1.5 KiB
C
83 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Linux kernel module helpers.
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*/
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#include <linux/of.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len)
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{
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const char *compat;
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char *c;
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struct property *p;
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ssize_t csize;
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ssize_t tsize;
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/*
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* Prevent a kernel oops in vsnprintf() -- it only allows passing a
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* NULL ptr when the length is also 0. Also filter out the negative
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* lengths...
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*/
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if ((len > 0 && !str) || len < 0)
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return -EINVAL;
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/* Name & Type */
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/* %p eats all alphanum characters, so %c must be used here */
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csize = snprintf(str, len, "of:N%pOFn%c%s", np, 'T',
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of_node_get_device_type(np));
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tsize = csize;
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len -= csize;
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if (str)
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str += csize;
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of_property_for_each_string(np, "compatible", p, compat) {
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csize = strlen(compat) + 1;
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tsize += csize;
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if (csize > len)
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continue;
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csize = snprintf(str, len, "C%s", compat);
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for (c = str; c; ) {
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c = strchr(c, ' ');
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if (c)
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*c++ = '_';
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}
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len -= csize;
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str += csize;
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}
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return tsize;
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}
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int of_request_module(const struct device_node *np)
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{
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char *str;
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ssize_t size;
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int ret;
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if (!np)
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return -ENODEV;
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size = of_modalias(np, NULL, 0);
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if (size < 0)
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return size;
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/* Reserve an additional byte for the trailing '\0' */
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size++;
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str = kmalloc(size, GFP_KERNEL);
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if (!str)
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return -ENOMEM;
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of_modalias(np, str, size);
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str[size - 1] = '\0';
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ret = request_module(str);
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kfree(str);
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return ret;
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}
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EXPORT_SYMBOL_GPL(of_request_module);
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