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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FORTIFY_STRING_H_
#define _LINUX_FORTIFY_STRING_H_
#include <linux/bug.h>
#include <linux/const.h>
#include <linux/limits.h>
#define __FORTIFY_INLINE extern __always_inline __gnu_inline __overloadable
#define __RENAME(x) __asm__(#x)
void fortify_panic(const char *name) __noreturn __cold;
void __read_overflow(void) __compiletime_error("detected read beyond size of object (1st parameter)");
void __read_overflow2(void) __compiletime_error("detected read beyond size of object (2nd parameter)");
void __read_overflow2_field(size_t avail, size_t wanted) __compiletime_warning("detected read beyond size of field (2nd parameter); maybe use struct_group()?");
void __write_overflow(void) __compiletime_error("detected write beyond size of object (1st parameter)");
void __write_overflow_field(size_t avail, size_t wanted) __compiletime_warning("detected write beyond size of field (1st parameter); maybe use struct_group()?");
#define __compiletime_strlen(p) \
({ \
char *__p = (char *)(p); \
size_t __ret = SIZE_MAX; \
const size_t __p_size = __member_size(p); \
if (__p_size != SIZE_MAX && \
__builtin_constant_p(*__p)) { \
size_t __p_len = __p_size - 1; \
if (__builtin_constant_p(__p[__p_len]) && \
__p[__p_len] == '\0') \
__ret = __builtin_strlen(__p); \
} \
__ret; \
})
#if defined(__SANITIZE_ADDRESS__)
#if !defined(CONFIG_CC_HAS_KASAN_MEMINTRINSIC_PREFIX) && !defined(CONFIG_GENERIC_ENTRY)
extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset);
extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove);
extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy);
#elif defined(CONFIG_KASAN_GENERIC)
extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(__asan_memset);
extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(__asan_memmove);
extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(__asan_memcpy);
#else /* CONFIG_KASAN_SW_TAGS */
extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(__hwasan_memset);
extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(__hwasan_memmove);
extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(__hwasan_memcpy);
#endif
extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr);
extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp);
extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat);
extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy);
extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
#else
#if defined(__SANITIZE_MEMORY__)
/*
* For KMSAN builds all memcpy/memset/memmove calls should be replaced by the
* corresponding __msan_XXX functions.
*/
#include <linux/kmsan_string.h>
#define __underlying_memcpy __msan_memcpy
#define __underlying_memmove __msan_memmove
#define __underlying_memset __msan_memset
#else
#define __underlying_memcpy __builtin_memcpy
#define __underlying_memmove __builtin_memmove
#define __underlying_memset __builtin_memset
#endif
#define __underlying_memchr __builtin_memchr
#define __underlying_memcmp __builtin_memcmp
#define __underlying_strcat __builtin_strcat
#define __underlying_strcpy __builtin_strcpy
#define __underlying_strlen __builtin_strlen
#define __underlying_strncat __builtin_strncat
#define __underlying_strncpy __builtin_strncpy
#endif
/**
* unsafe_memcpy - memcpy implementation with no FORTIFY bounds checking
*
* @dst: Destination memory address to write to
* @src: Source memory address to read from
* @bytes: How many bytes to write to @dst from @src
* @justification: Free-form text or comment describing why the use is needed
*
* This should be used for corner cases where the compiler cannot do the
* right thing, or during transitions between APIs, etc. It should be used
* very rarely, and includes a place for justification detailing where bounds
* checking has happened, and why existing solutions cannot be employed.
*/
#define unsafe_memcpy(dst, src, bytes, justification) \
__underlying_memcpy(dst, src, bytes)
/*
* Clang's use of __builtin_*object_size() within inlines needs hinting via
* __pass_*object_size(). The preference is to only ever use type 1 (member
* size, rather than struct size), but there remain some stragglers using
* type 0 that will be converted in the future.
*/
#if __has_builtin(__builtin_dynamic_object_size)
#define POS __pass_dynamic_object_size(1)
#define POS0 __pass_dynamic_object_size(0)
#else
#define POS __pass_object_size(1)
#define POS0 __pass_object_size(0)
#endif
#define __compiletime_lessthan(bounds, length) ( \
__builtin_constant_p((bounds) < (length)) && \
(bounds) < (length) \
)
/**
* strncpy - Copy a string to memory with non-guaranteed NUL padding
*
* @p: pointer to destination of copy
* @q: pointer to NUL-terminated source string to copy
* @size: bytes to write at @p
*
* If strlen(@q) >= @size, the copy of @q will stop after @size bytes,
* and @p will NOT be NUL-terminated
*
* If strlen(@q) < @size, following the copy of @q, trailing NUL bytes
* will be written to @p until @size total bytes have been written.
*
* Do not use this function. While FORTIFY_SOURCE tries to avoid
* over-reads of @q, it cannot defend against writing unterminated
* results to @p. Using strncpy() remains ambiguous and fragile.
* Instead, please choose an alternative, so that the expectation
* of @p's contents is unambiguous:
*
* +--------------------+--------------------+------------+
* | **p** needs to be: | padded to **size** | not padded |
* +====================+====================+============+
* | NUL-terminated | strscpy_pad() | strscpy() |
* +--------------------+--------------------+------------+
* | not NUL-terminated | strtomem_pad() | strtomem() |
* +--------------------+--------------------+------------+
*
* Note strscpy*()'s differing return values for detecting truncation,
* and strtomem*()'s expectation that the destination is marked with
* __nonstring when it is a character array.
*
*/
__FORTIFY_INLINE __diagnose_as(__builtin_strncpy, 1, 2, 3)
char *strncpy(char * const POS p, const char *q, __kernel_size_t size)
{
const size_t p_size = __member_size(p);
if (__compiletime_lessthan(p_size, size))
__write_overflow();
if (p_size < size)
fortify_panic(__func__);
return __underlying_strncpy(p, q, size);
}
extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen);
/**
* strnlen - Return bounded count of characters in a NUL-terminated string
*
* @p: pointer to NUL-terminated string to count.
* @maxlen: maximum number of characters to count.
*
* Returns number of characters in @p (NOT including the final NUL), or
* @maxlen, if no NUL has been found up to there.
*
*/
__FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen)
{
const size_t p_size = __member_size(p);
const size_t p_len = __compiletime_strlen(p);
size_t ret;
/* We can take compile-time actions when maxlen is const. */
if (__builtin_constant_p(maxlen) && p_len != SIZE_MAX) {
/* If p is const, we can use its compile-time-known len. */
if (maxlen >= p_size)
return p_len;
}
/* Do not check characters beyond the end of p. */
ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size);
if (p_size <= ret && maxlen != ret)
fortify_panic(__func__);
return ret;
}
/*
* Defined after fortified strnlen to reuse it. However, it must still be
* possible for strlen() to be used on compile-time strings for use in
* static initializers (i.e. as a constant expression).
*/
/**
* strlen - Return count of characters in a NUL-terminated string
*
* @p: pointer to NUL-terminated string to count.
*
* Do not use this function unless the string length is known at
* compile-time. When @p is unterminated, this function may crash
* or return unexpected counts that could lead to memory content
* exposures. Prefer strnlen().
*
* Returns number of characters in @p (NOT including the final NUL).
*
*/
#define strlen(p) \
__builtin_choose_expr(__is_constexpr(__builtin_strlen(p)), \
__builtin_strlen(p), __fortify_strlen(p))
__FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1)
__kernel_size_t __fortify_strlen(const char * const POS p)
{
const size_t p_size = __member_size(p);
__kernel_size_t ret;
/* Give up if we don't know how large p is. */
if (p_size == SIZE_MAX)
return __underlying_strlen(p);
ret = strnlen(p, p_size);
if (p_size <= ret)
fortify_panic(__func__);
return ret;
}
/* Defined after fortified strnlen() to reuse it. */
extern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(strscpy);
/**
* strscpy - Copy a C-string into a sized buffer
*
* @p: Where to copy the string to
* @q: Where to copy the string from
* @size: Size of destination buffer
*
* Copy the source string @q, or as much of it as fits, into the destination
* @p buffer. The behavior is undefined if the string buffers overlap. The
* destination @p buffer is always NUL terminated, unless it's zero-sized.
*
* Preferred to strncpy() since it always returns a valid string, and
* doesn't unnecessarily force the tail of the destination buffer to be
* zero padded. If padding is desired please use strscpy_pad().
*
* Returns the number of characters copied in @p (not including the
* trailing %NUL) or -E2BIG if @size is 0 or the copy of @q was truncated.
*/
__FORTIFY_INLINE ssize_t strscpy(char * const POS p, const char * const POS q, size_t size)
{
/* Use string size rather than possible enclosing struct size. */
const size_t p_size = __member_size(p);
const size_t q_size = __member_size(q);
size_t len;
/* If we cannot get size of p and q default to call strscpy. */
if (p_size == SIZE_MAX && q_size == SIZE_MAX)
return __real_strscpy(p, q, size);
/*
* If size can be known at compile time and is greater than
* p_size, generate a compile time write overflow error.
*/
if (__compiletime_lessthan(p_size, size))
__write_overflow();
/* Short-circuit for compile-time known-safe lengths. */
if (__compiletime_lessthan(p_size, SIZE_MAX)) {
len = __compiletime_strlen(q);
if (len < SIZE_MAX && __compiletime_lessthan(len, size)) {
__underlying_memcpy(p, q, len + 1);
return len;
}
}
/*
* This call protects from read overflow, because len will default to q
* length if it smaller than size.
*/
len = strnlen(q, size);
/*
* If len equals size, we will copy only size bytes which leads to
* -E2BIG being returned.
* Otherwise we will copy len + 1 because of the final '\O'.
*/
len = len == size ? size : len + 1;
/*
* Generate a runtime write overflow error if len is greater than
* p_size.
*/
if (len > p_size)
fortify_panic(__func__);
/*
* We can now safely call vanilla strscpy because we are protected from:
* 1. Read overflow thanks to call to strnlen().
* 2. Write overflow thanks to above ifs.
*/
return __real_strscpy(p, q, len);
}
/* Defined after fortified strlen() to reuse it. */
extern size_t __real_strlcat(char *p, const char *q, size_t avail) __RENAME(strlcat);
/**
* strlcat - Append a string to an existing string
*
* @p: pointer to %NUL-terminated string to append to
* @q: pointer to %NUL-terminated string to append from
* @avail: Maximum bytes available in @p
*
* Appends %NUL-terminated string @q after the %NUL-terminated
* string at @p, but will not write beyond @avail bytes total,
* potentially truncating the copy from @q. @p will stay
* %NUL-terminated only if a %NUL already existed within
* the @avail bytes of @p. If so, the resulting number of
* bytes copied from @q will be at most "@avail - strlen(@p) - 1".
*
* Do not use this function. While FORTIFY_SOURCE tries to avoid
* read and write overflows, this is only possible when the sizes
* of @p and @q are known to the compiler. Prefer building the
* string with formatting, via scnprintf(), seq_buf, or similar.
*
* Returns total bytes that _would_ have been contained by @p
* regardless of truncation, similar to snprintf(). If return
* value is >= @avail, the string has been truncated.
*
*/
__FORTIFY_INLINE
size_t strlcat(char * const POS p, const char * const POS q, size_t avail)
{
const size_t p_size = __member_size(p);
const size_t q_size = __member_size(q);
size_t p_len, copy_len;
size_t actual, wanted;
/* Give up immediately if both buffer sizes are unknown. */
if (p_size == SIZE_MAX && q_size == SIZE_MAX)
return __real_strlcat(p, q, avail);
p_len = strnlen(p, avail);
copy_len = strlen(q);
wanted = actual = p_len + copy_len;
/* Cannot append any more: report truncation. */
if (avail <= p_len)
return wanted;
/* Give up if string is already overflowed. */
if (p_size <= p_len)
fortify_panic(__func__);
if (actual >= avail) {
copy_len = avail - p_len - 1;
actual = p_len + copy_len;
}
/* Give up if copy will overflow. */
if (p_size <= actual)
fortify_panic(__func__);
__underlying_memcpy(p + p_len, q, copy_len);
p[actual] = '\0';
return wanted;
}
/* Defined after fortified strlcat() to reuse it. */
/**
* strcat - Append a string to an existing string
*
* @p: pointer to NUL-terminated string to append to
* @q: pointer to NUL-terminated source string to append from
*
* Do not use this function. While FORTIFY_SOURCE tries to avoid
* read and write overflows, this is only possible when the
* destination buffer size is known to the compiler. Prefer
* building the string with formatting, via scnprintf() or similar.
* At the very least, use strncat().
*
* Returns @p.
*
*/
__FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2)
char *strcat(char * const POS p, const char *q)
{
const size_t p_size = __member_size(p);
if (strlcat(p, q, p_size) >= p_size)
fortify_panic(__func__);
return p;
}
/**
* strncat - Append a string to an existing string
*
* @p: pointer to NUL-terminated string to append to
* @q: pointer to source string to append from
* @count: Maximum bytes to read from @q
*
* Appends at most @count bytes from @q (stopping at the first
* NUL byte) after the NUL-terminated string at @p. @p will be
* NUL-terminated.
*
* Do not use this function. While FORTIFY_SOURCE tries to avoid
* read and write overflows, this is only possible when the sizes
* of @p and @q are known to the compiler. Prefer building the
* string with formatting, via scnprintf() or similar.
*
* Returns @p.
*
*/
/* Defined after fortified strlen() and strnlen() to reuse them. */
__FORTIFY_INLINE __diagnose_as(__builtin_strncat, 1, 2, 3)
char *strncat(char * const POS p, const char * const POS q, __kernel_size_t count)
{
const size_t p_size = __member_size(p);
const size_t q_size = __member_size(q);
size_t p_len, copy_len;
if (p_size == SIZE_MAX && q_size == SIZE_MAX)
return __underlying_strncat(p, q, count);
p_len = strlen(p);
copy_len = strnlen(q, count);
if (p_size < p_len + copy_len + 1)
fortify_panic(__func__);
__underlying_memcpy(p + p_len, q, copy_len);
p[p_len + copy_len] = '\0';
return p;
}
__FORTIFY_INLINE void fortify_memset_chk(__kernel_size_t size,
const size_t p_size,
const size_t p_size_field)
{
if (__builtin_constant_p(size)) {
/*
* Length argument is a constant expression, so we
* can perform compile-time bounds checking where
* buffer sizes are also known at compile time.
*/
/* Error when size is larger than enclosing struct. */
if (__compiletime_lessthan(p_size_field, p_size) &&
__compiletime_lessthan(p_size, size))
__write_overflow();
/* Warn when write size is larger than dest field. */
if (__compiletime_lessthan(p_size_field, size))
__write_overflow_field(p_size_field, size);
}
/*
* At this point, length argument may not be a constant expression,
* so run-time bounds checking can be done where buffer sizes are
* known. (This is not an "else" because the above checks may only
* be compile-time warnings, and we want to still warn for run-time
* overflows.)
*/
/*
* Always stop accesses beyond the struct that contains the
* field, when the buffer's remaining size is known.
* (The SIZE_MAX test is to optimize away checks where the buffer
* lengths are unknown.)
*/
if (p_size != SIZE_MAX && p_size < size)
fortify_panic("memset");
}
#define __fortify_memset_chk(p, c, size, p_size, p_size_field) ({ \
size_t __fortify_size = (size_t)(size); \
fortify_memset_chk(__fortify_size, p_size, p_size_field), \
__underlying_memset(p, c, __fortify_size); \
})
/*
* __struct_size() vs __member_size() must be captured here to avoid
* evaluating argument side-effects further into the macro layers.
*/
#ifndef CONFIG_KMSAN
#define memset(p, c, s) __fortify_memset_chk(p, c, s, \
__struct_size(p), __member_size(p))
#endif
/*
* To make sure the compiler can enforce protection against buffer overflows,
* memcpy(), memmove(), and memset() must not be used beyond individual
* struct members. If you need to copy across multiple members, please use
* struct_group() to create a named mirror of an anonymous struct union.
* (e.g. see struct sk_buff.) Read overflow checking is currently only
* done when a write overflow is also present, or when building with W=1.
*
* Mitigation coverage matrix
* Bounds checking at:
* +-------+-------+-------+-------+
* | Compile time | Run time |
* memcpy() argument sizes: | write | read | write | read |
* dest source length +-------+-------+-------+-------+
* memcpy(known, known, constant) | y | y | n/a | n/a |
* memcpy(known, unknown, constant) | y | n | n/a | V |
* memcpy(known, known, dynamic) | n | n | B | B |
* memcpy(known, unknown, dynamic) | n | n | B | V |
* memcpy(unknown, known, constant) | n | y | V | n/a |
* memcpy(unknown, unknown, constant) | n | n | V | V |
* memcpy(unknown, known, dynamic) | n | n | V | B |
* memcpy(unknown, unknown, dynamic) | n | n | V | V |
* +-------+-------+-------+-------+
*
* y = perform deterministic compile-time bounds checking
* n = cannot perform deterministic compile-time bounds checking
* n/a = no run-time bounds checking needed since compile-time deterministic
* B = can perform run-time bounds checking (currently unimplemented)
* V = vulnerable to run-time overflow (will need refactoring to solve)
*
*/
__FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size,
const size_t p_size,
const size_t q_size,
const size_t p_size_field,
const size_t q_size_field,
const char *func)
{
if (__builtin_constant_p(size)) {
/*
* Length argument is a constant expression, so we
* can perform compile-time bounds checking where
* buffer sizes are also known at compile time.
*/
/* Error when size is larger than enclosing struct. */
if (__compiletime_lessthan(p_size_field, p_size) &&
__compiletime_lessthan(p_size, size))
__write_overflow();
if (__compiletime_lessthan(q_size_field, q_size) &&
__compiletime_lessthan(q_size, size))
__read_overflow2();
/* Warn when write size argument larger than dest field. */
if (__compiletime_lessthan(p_size_field, size))
__write_overflow_field(p_size_field, size);
/*
* Warn for source field over-read when building with W=1
* or when an over-write happened, so both can be fixed at
* the same time.
*/
if ((IS_ENABLED(KBUILD_EXTRA_WARN1) ||
__compiletime_lessthan(p_size_field, size)) &&
__compiletime_lessthan(q_size_field, size))
__read_overflow2_field(q_size_field, size);
}
/*
* At this point, length argument may not be a constant expression,
* so run-time bounds checking can be done where buffer sizes are
* known. (This is not an "else" because the above checks may only
* be compile-time warnings, and we want to still warn for run-time
* overflows.)
*/
/*
* Always stop accesses beyond the struct that contains the
* field, when the buffer's remaining size is known.
* (The SIZE_MAX test is to optimize away checks where the buffer
* lengths are unknown.)
*/
if ((p_size != SIZE_MAX && p_size < size) ||
(q_size != SIZE_MAX && q_size < size))
fortify_panic(func);
/*
* Warn when writing beyond destination field size.
*
* We must ignore p_size_field == 0 for existing 0-element
* fake flexible arrays, until they are all converted to
* proper flexible arrays.
*
* The implementation of __builtin_*object_size() behaves
* like sizeof() when not directly referencing a flexible
* array member, which means there will be many bounds checks
* that will appear at run-time, without a way for them to be
* detected at compile-time (as can be done when the destination
* is specifically the flexible array member).
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101832
*/
if (p_size_field != 0 && p_size_field != SIZE_MAX &&
p_size != p_size_field && p_size_field < size)
return true;
return false;
}
#define __fortify_memcpy_chk(p, q, size, p_size, q_size, \
p_size_field, q_size_field, op) ({ \
const size_t __fortify_size = (size_t)(size); \
const size_t __p_size = (p_size); \
const size_t __q_size = (q_size); \
const size_t __p_size_field = (p_size_field); \
const size_t __q_size_field = (q_size_field); \
WARN_ONCE(fortify_memcpy_chk(__fortify_size, __p_size, \
__q_size, __p_size_field, \
__q_size_field, #op), \
#op ": detected field-spanning write (size %zu) of single %s (size %zu)\n", \
__fortify_size, \
"field \"" #p "\" at " FILE_LINE, \
__p_size_field); \
__underlying_##op(p, q, __fortify_size); \
})
/*
* Notes about compile-time buffer size detection:
*
* With these types...
*
* struct middle {
* u16 a;
* u8 middle_buf[16];
* int b;
* };
* struct end {
* u16 a;
* u8 end_buf[16];
* };
* struct flex {
* int a;
* u8 flex_buf[];
* };
*
* void func(TYPE *ptr) { ... }
*
* Cases where destination size cannot be currently detected:
* - the size of ptr's object (seemingly by design, gcc & clang fail):
* __builtin_object_size(ptr, 1) == SIZE_MAX
* - the size of flexible arrays in ptr's obj (by design, dynamic size):
* __builtin_object_size(ptr->flex_buf, 1) == SIZE_MAX
* - the size of ANY array at the end of ptr's obj (gcc and clang bug):
* __builtin_object_size(ptr->end_buf, 1) == SIZE_MAX
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836
*
* Cases where destination size is currently detected:
* - the size of non-array members within ptr's object:
* __builtin_object_size(ptr->a, 1) == 2
* - the size of non-flexible-array in the middle of ptr's obj:
* __builtin_object_size(ptr->middle_buf, 1) == 16
*
*/
/*
* __struct_size() vs __member_size() must be captured here to avoid
* evaluating argument side-effects further into the macro layers.
*/
#define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \
__struct_size(p), __struct_size(q), \
__member_size(p), __member_size(q), \
memcpy)
#define memmove(p, q, s) __fortify_memcpy_chk(p, q, s, \
__struct_size(p), __struct_size(q), \
__member_size(p), __member_size(q), \
memmove)
extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan);
__FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size)
{
const size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
if (p_size < size)
fortify_panic(__func__);
return __real_memscan(p, c, size);
}
__FORTIFY_INLINE __diagnose_as(__builtin_memcmp, 1, 2, 3)
int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t size)
{
const size_t p_size = __struct_size(p);
const size_t q_size = __struct_size(q);
if (__builtin_constant_p(size)) {
if (__compiletime_lessthan(p_size, size))
__read_overflow();
if (__compiletime_lessthan(q_size, size))
__read_overflow2();
}
if (p_size < size || q_size < size)
fortify_panic(__func__);
return __underlying_memcmp(p, q, size);
}
__FORTIFY_INLINE __diagnose_as(__builtin_memchr, 1, 2, 3)
void *memchr(const void * const POS0 p, int c, __kernel_size_t size)
{
const size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
if (p_size < size)
fortify_panic(__func__);
return __underlying_memchr(p, c, size);
}
void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv);
__FORTIFY_INLINE void *memchr_inv(const void * const POS0 p, int c, size_t size)
{
const size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
if (p_size < size)
fortify_panic(__func__);
return __real_memchr_inv(p, c, size);
}
extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup)
__realloc_size(2);
__FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp)
{
const size_t p_size = __struct_size(p);
if (__compiletime_lessthan(p_size, size))
__read_overflow();
if (p_size < size)
fortify_panic(__func__);
return __real_kmemdup(p, size, gfp);
}
/**
* strcpy - Copy a string into another string buffer
*
* @p: pointer to destination of copy
* @q: pointer to NUL-terminated source string to copy
*
* Do not use this function. While FORTIFY_SOURCE tries to avoid
* overflows, this is only possible when the sizes of @q and @p are
* known to the compiler. Prefer strscpy(), though note its different
* return values for detecting truncation.
*
* Returns @p.
*
*/
/* Defined after fortified strlen to reuse it. */
__FORTIFY_INLINE __diagnose_as(__builtin_strcpy, 1, 2)
char *strcpy(char * const POS p, const char * const POS q)
{
const size_t p_size = __member_size(p);
const size_t q_size = __member_size(q);
size_t size;
/* If neither buffer size is known, immediately give up. */
if (__builtin_constant_p(p_size) &&
__builtin_constant_p(q_size) &&
p_size == SIZE_MAX && q_size == SIZE_MAX)
return __underlying_strcpy(p, q);
size = strlen(q) + 1;
/* Compile-time check for const size overflow. */
if (__compiletime_lessthan(p_size, size))
__write_overflow();
/* Run-time check for dynamic size overflow. */
if (p_size < size)
fortify_panic(__func__);
__underlying_memcpy(p, q, size);
return p;
}
/* Don't use these outside the FORITFY_SOURCE implementation */
#undef __underlying_memchr
#undef __underlying_memcmp
#undef __underlying_strcat
#undef __underlying_strcpy
#undef __underlying_strlen
#undef __underlying_strncat
#undef __underlying_strncpy
#undef POS
#undef POS0
#endif /* _LINUX_FORTIFY_STRING_H_ */
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