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cf7385cb26
In of_modalias(), if the buffer happens to be too small even for the 1st
snprintf() call, the len parameter will become negative and str parameter
(if not NULL initially) will point beyond the buffer's end. Add the buffer
overflow check after the 1st snprintf() call and fix such check after the
strlen() call (accounting for the terminating NUL char).
Fixes: bc575064d6 ("of/device: use of_property_for_each_string to parse compatible strings")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/bbfc6be0-c687-62b6-d015-5141b93f313e@omp.ru
Signed-off-by: Rob Herring <robh@kernel.org>
76 lines
1.4 KiB
C
76 lines
1.4 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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/* 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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if (csize >= len)
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csize = len > 0 ? len - 1 : 0;
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len -= csize;
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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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