From b4c145b73c8254b7a509a5fcaee8cb84ebd67930 Mon Sep 17 00:00:00 2001 From: markj Date: Mon, 13 Apr 2015 01:42:24 +0000 Subject: MFC r280834: Bound the number of frames traversed when executing the ustackdepth action. --- sys/cddl/dev/dtrace/i386/dtrace_isa.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) (limited to 'sys/cddl/dev/dtrace/i386/dtrace_isa.c') diff --git a/sys/cddl/dev/dtrace/i386/dtrace_isa.c b/sys/cddl/dev/dtrace/i386/dtrace_isa.c index 21a8154..6c261bf 100644 --- a/sys/cddl/dev/dtrace/i386/dtrace_isa.c +++ b/sys/cddl/dev/dtrace/i386/dtrace_isa.c @@ -55,6 +55,8 @@ uint16_t dtrace_fuword16_nocheck(void *); uint32_t dtrace_fuword32_nocheck(void *); uint64_t dtrace_fuword64_nocheck(void *); +int dtrace_ustackdepth_max = 2048; + void dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes, uint32_t *intrpc) @@ -113,11 +115,13 @@ dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc, uintptr_t oldcontext = lwp->lwp_oldcontext; /* XXX signal stack. */ size_t s1, s2; #endif + uintptr_t oldsp; volatile uint16_t *flags = (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags; int ret = 0; ASSERT(pcstack == NULL || pcstack_limit > 0); + ASSERT(dtrace_ustackdepth_max > 0); #ifdef notyet /* XXX signal stack. */ if (p->p_model == DATAMODEL_NATIVE) { @@ -130,7 +134,16 @@ dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc, #endif while (pc != 0) { - ret++; + /* + * We limit the number of times we can go around this + * loop to account for a circular stack. + */ + if (ret++ >= dtrace_ustackdepth_max) { + *flags |= CPU_DTRACE_BADSTACK; + cpu_core[curcpu].cpuc_dtrace_illval = sp; + break; + } + if (pcstack != NULL) { *pcstack++ = (uint64_t)pc; pcstack_limit--; @@ -141,6 +154,8 @@ dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc, if (sp == 0) break; + oldsp = sp; + #ifdef notyet /* XXX signal stack. */ if (oldcontext == sp + s1 || oldcontext == sp + s2) { if (p->p_model == DATAMODEL_NATIVE) { @@ -179,6 +194,12 @@ dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc, sp = dtrace_fuword32((void *)sp); #endif /* ! notyet */ + if (sp == oldsp) { + *flags |= CPU_DTRACE_BADSTACK; + cpu_core[curcpu].cpuc_dtrace_illval = sp; + break; + } + /* * This is totally bogus: if we faulted, we're going to clear * the fault and break. This is to deal with the apparently -- cgit v1.1