Commit 7522060c authored by Ingo Molnar's avatar Ingo Molnar
Browse files

perf report: Add validation of call-chain entries 



Add boundary checks for call-chain events. In case of corrupted
entries we could crash otherwise.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b25bcf2f

include/linux/perf_counter.h

+10 −10
Original line number Diff line number Diff line
@@ -337,6 +337,16 @@ enum perf_event_type { 
	 */

};



#define MAX_STACK_DEPTH			255



struct perf_callchain_entry {

	__u16				nr;

	__u16				hv;

	__u16				kernel;

	__u16				user;

	__u64				ip[MAX_STACK_DEPTH];

};



#ifdef __KERNEL__

/*

 * Kernel-internal data types and definitions:
@@ -652,16 +662,6 @@ extern void perf_counter_fork(struct task_struct *tsk); 


extern void perf_counter_task_migration(struct task_struct *task, int cpu);



#define MAX_STACK_DEPTH			255



struct perf_callchain_entry {

	u16				nr;

	u16				hv;

	u16				kernel;

	u16				user;

	u64				ip[MAX_STACK_DEPTH];

};



extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);



extern int sysctl_perf_counter_paranoid;

tools/perf/builtin-report.c

+46 −28
Original line number Diff line number Diff line
@@ -39,6 +39,8 @@ static int dump_trace = 0; 
#define cdprintf(x...)	do { if (dump_trace) color_fprintf(stdout, color, x); } while (0)



static int		verbose;

#define eprintf(x...)	do { if (verbose) fprintf(stderr, x); } while (0)



static int		full_paths;



static unsigned long	page_size;
@@ -47,14 +49,6 @@ static unsigned long mmap_window = 32; 
static char		*parent_pattern = "^sys_|^do_page_fault";

static regex_t		parent_regex;



struct ip_chain_event {

	__u16 nr;

	__u16 hv;

	__u16 kernel;

	__u16 user;

	__u64 ips[];

};



struct ip_event {

	struct perf_event_header header;

	__u64 ip;
@@ -131,15 +125,11 @@ static struct dso *dsos__findnew(const char *name) 


	nr = dso__load(dso, NULL, verbose);

	if (nr < 0) {

		if (verbose)

			fprintf(stderr, "Failed to open: %s\n", name);

		eprintf("Failed to open: %s\n", name);

		goto out_delete_dso;

	}

	if (!nr && verbose) {

		fprintf(stderr,

		"No symbols found in: %s, maybe install a debug package?\n",

				name);

	}

	if (!nr)

		eprintf("No symbols found in: %s, maybe install a debug package?\n", name);



	dsos__add(dso);
@@ -844,7 +834,7 @@ static struct symbol *call__match(struct symbol *sym) 


static int

hist_entry__add(struct thread *thread, struct map *map, struct dso *dso,

		struct symbol *sym, __u64 ip, struct ip_chain_event *chain,

		struct symbol *sym, __u64 ip, struct perf_callchain_entry *chain,

		char level, __u64 count)

{

	struct rb_node **p = &hist.rb_node;
@@ -868,7 +858,7 @@ hist_entry__add(struct thread *thread, struct map *map, struct dso *dso, 
		__u64 ip;



		for (i = 0; i < chain->kernel; i++) {

			ip = chain->ips[nr + i];

			ip = chain->ip[nr + i];

			dso = kernel_dso;

			sym = resolve_symbol(thread, NULL, &dso, &ip);

			entry.parent = call__match(sym);
@@ -878,7 +868,7 @@ hist_entry__add(struct thread *thread, struct map *map, struct dso *dso, 
		nr += i;



		for (i = 0; i < chain->user; i++) {

			ip = chain->ips[nr + i];

			ip = chain->ip[nr + i];

			sym = resolve_symbol(thread, NULL, NULL, &ip);

			entry.parent = call__match(sym);

			if (entry.parent)
@@ -1080,6 +1070,30 @@ static unsigned long total = 0, 
		     total_fork = 0,

		     total_unknown = 0;



static int validate_chain(struct perf_callchain_entry *chain, event_t *event)

{

	unsigned int chain_size;



	if (chain->nr > MAX_STACK_DEPTH)

		return -1;

	if (chain->hv > MAX_STACK_DEPTH)

		return -1;

	if (chain->kernel > MAX_STACK_DEPTH)

		return -1;

	if (chain->user > MAX_STACK_DEPTH)

		return -1;

	if (chain->hv + chain->kernel + chain->user != chain->nr)

		return -1;



	chain_size = event->header.size;

	chain_size -= (unsigned long)&event->ip.__more_data - (unsigned long)event;



	if (chain->nr*sizeof(__u64) > chain_size)

		return -1;



	return 0;

}



static int

process_overflow_event(event_t *event, unsigned long offset, unsigned long head)

{
@@ -1091,7 +1105,7 @@ process_overflow_event(event_t *event, unsigned long offset, unsigned long head) 
	__u64 period = 1;

	struct map *map = NULL;

	void *more_data = event->ip.__more_data;

	struct ip_chain_event *chain = NULL;

	struct perf_callchain_entry *chain = NULL;



	if (event->header.type & PERF_SAMPLE_PERIOD) {

		period = *(__u64 *)more_data;
@@ -1111,21 +1125,26 @@ process_overflow_event(event_t *event, unsigned long offset, unsigned long head) 


		chain = (void *)more_data;



		if (dump_trace) {

		dprintf("... chain: u:%d, k:%d, nr:%d\n",

			chain->user,

			chain->kernel,

			chain->nr);



		if (validate_chain(chain, event) < 0) {

			eprintf("call-chain problem with event, skipping it.\n");

			return 0;

		}



		if (dump_trace) {

			for (i = 0; i < chain->nr; i++)

				dprintf("..... %2d: %016Lx\n", i, chain->ips[i]);

				dprintf("..... %2d: %016Lx\n", i, chain->ip[i]);

		}

	}



	dprintf(" ... thread: %s:%d\n", thread->comm, thread->pid);



	if (thread == NULL) {

		fprintf(stderr, "problem processing %d event, skipping it.\n",

		eprintf("problem processing %d event, skipping it.\n",

			event->header.type);

		return -1;

	}
@@ -1153,8 +1172,7 @@ process_overflow_event(event_t *event, unsigned long offset, unsigned long head) 
		struct symbol *sym = resolve_symbol(thread, &map, &dso, &ip);



		if (hist_entry__add(thread, map, dso, sym, ip, chain, level, period)) {

			fprintf(stderr,

		"problem incrementing symbol count, skipping event\n");

			eprintf("problem incrementing symbol count, skipping event\n");

			return -1;

		}

	}

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