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| author |   Florian Weimer <fweimer@redhat.com> | 2018-06-01 10:41:03 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2018-06-01 10:41:03 +0200 |
| commit | 4e8a6346cd3da2d88bbad745a1769260d36f2783 (patch) | |
| tree | dcf9deeedd5263469fa425574c0ac671a8b43c2a /libio/vasprintf.c | |
| parent | Update ulps with "make regen-ulps" on AMD Ryzen 7 1800X. (diff) | |
| download | glibc-4e8a6346cd3da2d88bbad745a1769260d36f2783.tar.gz glibc-4e8a6346cd3da2d88bbad745a1769260d36f2783.tar.bz2 glibc-4e8a6346cd3da2d88bbad745a1769260d36f2783.zip | |
libio: Avoid _allocate_buffer, _free_buffer function pointers [BZ #23236]
These unmangled function pointers reside on the heap and could
be targeted by exploit writers, effectively bypassing libio vtable
validation. Instead, we ignore these pointers and always call
malloc or free.
In theory, this is a backwards-incompatible change, but using the
global heap instead of the user-supplied callback functions should
have little application impact. (The old libstdc++ implementation
exposed this functionality via a public, undocumented constructor
in its strstreambuf class.)
Diffstat (limited to 'libio/vasprintf.c')
| -rw-r--r-- | libio/vasprintf.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/libio/vasprintf.c b/libio/vasprintf.c index 08218ddbe7..6c35d2b108 100644 --- a/libio/vasprintf.c +++ b/libio/vasprintf.c @@ -54,8 +54,8 @@ _IO_vasprintf (char **result_ptr, const char *format, va_list args) _IO_JUMPS (&sf._sbf) = &_IO_str_jumps; _IO_str_init_static_internal (&sf, string, init_string_size, string); sf._sbf._f._flags &= ~_IO_USER_BUF; - sf._s._allocate_buffer = (_IO_alloc_type) malloc; - sf._s._free_buffer = (_IO_free_type) free; + sf._s._allocate_buffer_unused = (_IO_alloc_type) malloc; + sf._s._free_buffer_unused = (_IO_free_type) free; ret = _IO_vfprintf (&sf._sbf._f, format, args); if (ret < 0) { |