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| author | Dennis Wölfing <denniswoelfing@gmx.de> | 2017-05-30 18:26:19 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2017-05-30 18:27:57 -0300 |
| commit | 2e0bbbfbf95fc9e22692e93658a6fbdd2d4554da (patch) | |
| tree | 662856c19816b2b441dbfda3e15ca771eb303e5f /malloc/malloc-internal.h | |
| parent | 4f26ef1b67287d1f2c32865f7d79c13abda81915 (diff) | |
| download | glibc-2e0bbbfbf95fc9e22692e93658a6fbdd2d4554da.tar.gz glibc-2e0bbbfbf95fc9e22692e93658a6fbdd2d4554da.tar.xz glibc-2e0bbbfbf95fc9e22692e93658a6fbdd2d4554da.zip | |
Add reallocarray function
The reallocarray function is an extension from OpenBSD. It is an
integer-overflow-safe replacement for realloc(p, X*Y) and
malloc(X*Y) (realloc(NULL, X*Y)). It can therefore help in preventing
certain security issues in code.
This is an updated version of a patch originally submitted by Rüdiger
Sonderfeld in May 2014 [1].
Checked on i686-linux-gnu and x86_64-linux-gnu.
[1] <https://sourceware.org/ml/libc-alpha/2014-05/msg00481.html>.
2017-05-30 Dennis Wölfing <denniswoelfing@gmx.de>
Rüdiger Sonderfeld <ruediger@c-plusplus.de>
* include/stdlib.h (__libc_reallocarray): New declaration.
* malloc/Makefile (routines): Add reallocarray.
(tests): Add tst-reallocarray.c.
* malloc/Versions: Add reallocarray and __libc_reallocarray.
* malloc/malloc-internal.h (check_mul_overflow_size_t): New inline
function.
* malloc/malloc.h (reallocarray): New declaration.
* stdlib/stdlib.h (reallocarray): Likewise.
* malloc/reallocarray.c: New file.
* malloc/tst-reallocarray.c: New test file.
* manual/memory.texi: Document reallocarray.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist: Add reallocarray.
* sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/tilepro/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
Diffstat (limited to 'malloc/malloc-internal.h')
| -rw-r--r-- | malloc/malloc-internal.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h index de6103d7e1..dbd801a58e 100644 --- a/malloc/malloc-internal.h +++ b/malloc/malloc-internal.h @@ -81,5 +81,24 @@ void __malloc_fork_unlock_parent (void) internal_function attribute_hidden; /* Called in the child process after a fork. */ void __malloc_fork_unlock_child (void) internal_function attribute_hidden; +/* Set *RESULT to LEFT * RIGHT. Return true if the multiplication + overflowed. */ +static inline bool +check_mul_overflow_size_t (size_t left, size_t right, size_t *result) +{ +#if __GNUC__ >= 5 + return __builtin_mul_overflow (left, right, result); +#else + /* size_t is unsigned so the behavior on overflow is defined. */ + *result = left * right; + size_t half_size_t = ((size_t) 1) << (8 * sizeof (size_t) / 2); + if (__glibc_unlikely ((left | right) >= half_size_t)) + { + if (__glibc_unlikely (right != 0 && *result / right != left)) + return true; + } + return false; +#endif +} #endif /* _MALLOC_INTERNAL_H */ |