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[PATCH] libio: freopen of default streams crashes in old programs [BZ #24632]
- From: Florian Weimer <fweimer at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Mon, 03 Jun 2019 15:34:26 +0200
- Subject: [PATCH] libio: freopen of default streams crashes in old programs [BZ #24632]
As seen with very old i386 GCC binaries.
2019-06-03 Florian Weimer <fweimer@redhat.com>
[BZ #24632]
* libio/libioP.h (_IO_JUMPS_FUNC_UPDATE): New macro.
* libio/freopen.c (freopen): Use it.
diff --git a/libio/freopen.c b/libio/freopen.c
index 17b00258cd..82e39f5028 100644
--- a/libio/freopen.c
+++ b/libio/freopen.c
@@ -62,7 +62,7 @@ freopen (const char *filename, const char *mode, FILE *fp)
to the old libio may be passed into shared C library and wind
up here. */
_IO_old_file_close_it (fp);
- _IO_JUMPS_FILE_plus (fp) = &_IO_old_file_jumps;
+ _IO_JUMPS_FUNC_UPDATE (fp, &_IO_old_file_jumps);
result = _IO_old_file_fopen (fp, gfilename, mode);
}
else
diff --git a/libio/libioP.h b/libio/libioP.h
index 66afaa8968..f17c6e68e4 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -108,9 +108,14 @@
(IO_validate_vtable \
(*(struct _IO_jump_t **) ((void *) &_IO_JUMPS_FILE_plus (THIS) \
+ (THIS)->_vtable_offset)))
+# define _IO_JUMPS_FUNC_UPDATE(THIS, VTABLE) \
+ (*(const struct _IO_jump_t **) ((void *) &_IO_JUMPS_FILE_plus (THIS) \
+ + (THIS)->_vtable_offset) = (VTABLE))
# define _IO_vtable_offset(THIS) (THIS)->_vtable_offset
#else
# define _IO_JUMPS_FUNC(THIS) (IO_validate_vtable (_IO_JUMPS_FILE_plus (THIS)))
+# define _IO_JUMPS_FUNC_UPDATE(THIS, VTABLE) \
+ (_IO_JUMPS_FILE_plus (THIS) = (VTABLE))
# define _IO_vtable_offset(THIS) 0
#endif
#define _IO_WIDE_JUMPS_FUNC(THIS) _IO_WIDE_JUMPS(THIS)