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0b0d5701a8
[ Upstream commitcf7385cb26] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
84 lines
1.6 KiB
C
84 lines
1.6 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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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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