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Refine syscall_linkage attribute semantics to fix security hole. 

* config/ia64/ia64.c (ia64_epilogue_uses): For syscall_linkage
	functions, drop current_function_args_info.words test.
	(ia64_compute_frame_size): Mark syscall_linkage functions as
	using eight input registers.

From-SVN: r39965
This commit is contained in:
David Mosberger 2001-02-21 21:50:16 +00:00 committed by Jim Wilson
parent e9ece3bcbc
commit 3f67ac08f3
2 changed files with 16 additions and 3 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2001-02-21 David Mosberger <davidm@hpl.hp.com>
* config/ia64/ia64.c (ia64_epilogue_uses): For syscall_linkage
functions, drop current_function_args_info.words test.
(ia64_compute_frame_size): Mark syscall_linkage functions as
using eight input registers.
2001-02-21 Loren J. Rittle <ljrittle@acm.org>
Bruce Korb <bkorb@gnu.org>

12
gcc/config/ia64/ia64.c
View File

@ -1317,7 +1317,13 @@ ia64_compute_frame_size (size)
break;
current_frame_info.n_local_regs = regno - LOC_REG (0) + 1;
if (cfun->machine->n_varargs > 0)
/* For functions marked with the syscall_linkage attribute, we must mark
all eight input registers as in use, so that locals aren't visible to
the caller. */
if (cfun->machine->n_varargs > 0
|| lookup_attribute ("syscall_linkage",
TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl))))
current_frame_info.n_input_regs = 8;
else
{
@ -6040,10 +6046,10 @@ ia64_epilogue_uses (regno)
registers are marked as live at all function exits. This prevents the
register allocator from using the input registers, which in turn makes it
possible to restart a system call after an interrupt without having to
save/restore the input registers. */
save/restore the input registers. This also prevents kernel data from
leaking to application code. */
if (IN_REGNO_P (regno)
&& (regno < IN_REG (current_function_args_info.words))
&& lookup_attribute ("syscall_linkage",
TYPE_ATTRIBUTES (TREE_TYPE (current_function_decl))))
return 1;