[IA64] Improve unwind checking.
This patch adds some sanity checks to keep register and memory stack
pointers in the unw_frame_info structure within the tasks stack address
range.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/ia64/kernel/unwind.c b/arch/ia64/kernel/unwind.c
index 7d3dd6c..b0b08b5 100644
--- a/arch/ia64/kernel/unwind.c
+++ b/arch/ia64/kernel/unwind.c
@@ -1860,7 +1860,7 @@
unw_unwind (struct unw_frame_info *info)
{
unsigned long prev_ip, prev_sp, prev_bsp;
- unsigned long ip, pr, num_regs;
+ unsigned long ip, pr, num_regs, rp_loc, pfs_loc;
STAT(unsigned long start, flags;)
int retval;
@@ -1870,14 +1870,16 @@
prev_sp = info->sp;
prev_bsp = info->bsp;
- /* restore the ip */
- if (!info->rp_loc) {
+ /* validate the return IP pointer */
+ rp_loc = (unsigned long) info->rp_loc;
+ if ((rp_loc < info->regstk.limit) || (rp_loc > info->regstk.top)) {
/* FIXME: should really be level 0 but it occurs too often. KAO */
UNW_DPRINT(1, "unwind.%s: failed to locate return link (ip=0x%lx)!\n",
__FUNCTION__, info->ip);
STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
return -1;
}
+ /* restore the ip */
ip = info->ip = *info->rp_loc;
if (ip < GATE_ADDR) {
UNW_DPRINT(2, "unwind.%s: reached user-space (ip=0x%lx)\n", __FUNCTION__, ip);
@@ -1885,12 +1887,14 @@
return -1;
}
- /* restore the cfm: */
- if (!info->pfs_loc) {
+ /* validate the previous stack frame pointer */
+ pfs_loc = (unsigned long) info->pfs_loc;
+ if ((pfs_loc < info->regstk.limit) || (pfs_loc > info->regstk.top)) {
UNW_DPRINT(0, "unwind.%s: failed to locate ar.pfs!\n", __FUNCTION__);
STAT(unw.stat.api.unwind_time += ia64_get_itc() - start; local_irq_restore(flags));
return -1;
}
+ /* restore the cfm: */
info->cfm_loc = info->pfs_loc;
/* restore the bsp: */
@@ -1992,13 +1996,16 @@
memset(info, 0, sizeof(*info));
rbslimit = (unsigned long) t + IA64_RBS_OFFSET;
+ stklimit = (unsigned long) t + IA64_STK_OFFSET;
+
rbstop = sw->ar_bspstore;
- if (rbstop - (unsigned long) t >= IA64_STK_OFFSET)
+ if (rbstop > stklimit || rbstop < rbslimit)
rbstop = rbslimit;
- stklimit = (unsigned long) t + IA64_STK_OFFSET;
if (stktop <= rbstop)
stktop = rbstop;
+ if (stktop > stklimit)
+ stktop = stklimit;
info->regstk.limit = rbslimit;
info->regstk.top = rbstop;