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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 /ChangeLog | |
| parent | 50d004c91c942221b862a4a13a4b5f78cfb0d595 (diff) | |
| download | glibc-4e8a6346cd3da2d88bbad745a1769260d36f2783.tar.xz 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 'ChangeLog')
| -rw-r--r-- | ChangeLog | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -1,3 +1,27 @@ +2018-06-01 Florian Weimer <fweimer@redhat.com> + + [BZ #23236] + * libio/strfile.h (struct _IO_str_fields): Rename members to + discourage their use and add comment. + (_IO_STR_DYNAMIC): Remove unused macro. + * libio/strops.c (_IO_str_init_static_internal): Do not use + callback pointers. Call malloc and free. + (_IO_str_overflow): Do not use callback pointers. Call malloc + and free. + (enlarge_userbuf): Likewise. + (_IO_str_finish): Call free. + * libio/wstrops.c (_IO_wstr_init_static): Initialize + _allocate_buffer_unused. + (_IO_wstr_overflow): Do not use callback pointers. Call malloc + and free. + (enlarge_userbuf): Likewise. + (_IO_wstr_finish): Call free. + * debug/vasprintf_chk.c (__vasprintf_chk): Initialize + _allocate_buffer_unused, _free_buffer_unused. + * libio/memstream.c (__open_memstream): Likewise. + * libio/vasprintf.c (_IO_vasprintf): Likewise. + * libio/wmemstream.c (open_wmemstream): Likewise. + 2018-05-30 Paul Pluzhnikov <ppluzhnikov@google.com> * sysdeps/x86_64/fpu/libm-test-ulps (log_vlen8_avx2): Update for |