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@xxxxxxx> Index: linux-tot-20070517/arch/ia64/kernel/unwind.c =================================================================== --- linux-tot-20070517.orig/arch/ia64/kernel/unwind.c 2007-05-18 11:23:10.772996962 -0500 +++ linux-tot-20070517/arch/ia64/kernel/unwind.c 2007-05-18 11:23:19.450056538 -0500 @@ -1860,7 +1860,7 @@ int 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 @@ unw_unwind (struct unw_frame_info *info) 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 @@ unw_unwind (struct unw_frame_info *info) 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 @@ init_frame_info (struct unw_frame_info * 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; - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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