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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 /debug | |
| parent | 50d004c91c942221b862a4a13a4b5f78cfb0d595 (diff) | |
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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 'debug')
| -rw-r--r-- | debug/vasprintf_chk.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/debug/vasprintf_chk.c b/debug/vasprintf_chk.c index 46603d9538..48b4741651 100644 --- a/debug/vasprintf_chk.c +++ b/debug/vasprintf_chk.c @@ -55,8 +55,8 @@ __vasprintf_chk (char **result_ptr, int flags, const char *format, _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; /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n can only come from read-only format strings. */ |