X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/8a3053a07cee346dca737a5670e546fd26a7c9d6..143464d58d2bd6378e74eec636961ceb0d32fb91:/osfmk/kern/telemetry.c?ds=sidebyside

diff --git a/osfmk/kern/telemetry.c b/osfmk/kern/telemetry.c
index 724f8a2af..15b025418 100644
--- a/osfmk/kern/telemetry.c
+++ b/osfmk/kern/telemetry.c
@@ -73,6 +73,7 @@ void telemetry_take_sample(thread_t thread, uint8_t microsnapshot_flags);
 #define TELEMETRY_MAX_BUFFER_SIZE (64*1024)
 
 #define	TELEMETRY_DEFAULT_NOTIFY_LEEWAY (4*1024) // Userland gets 4k of leeway to collect data after notification
+#define	TELEMETRY_MAX_UUID_COUNT (128) // Max of 128 non-shared-cache UUIDs to log for symbolication
 
 uint32_t 			telemetry_sample_rate = 0;
 volatile boolean_t 	telemetry_needs_record = FALSE;
@@ -421,6 +422,14 @@ void telemetry_take_sample(thread_t thread, uint8_t microsnapshot_flags)
 		uuid_info_count = 0;
 	}
 
+	/*
+	 * Don't copy in an unbounded amount of memory. The main binary and interesting
+	 * non-shared-cache libraries should be in the first few images.
+	 */
+	if (uuid_info_count > TELEMETRY_MAX_UUID_COUNT) {
+		uuid_info_count = TELEMETRY_MAX_UUID_COUNT;
+	}
+
 	uint32_t uuid_info_size = (uint32_t)(task_has_64BitAddr(thread->task) ? sizeof(struct user64_dyld_uuid_info) : sizeof(struct user32_dyld_uuid_info));
 	uint32_t uuid_info_array_size = uuid_info_count * uuid_info_size;
 	char	 *uuid_info_array = NULL;
@@ -483,6 +492,10 @@ copytobuffer:
 		 */
 		telemetry_buffer_end_point = current_record_start;
 		telemetry_buffer_current_position = 0;
+		if (current_record_start == 0) {
+			/* This sample is too large to fit in the buffer even when we started at 0, so skip it */
+			goto cancel_sample;
+		}
 		goto copytobuffer;
 	}
 
@@ -499,6 +512,10 @@ copytobuffer:
 	if ((telemetry_buffer_size - telemetry_buffer_current_position) < sizeof(struct task_snapshot)) {
 		telemetry_buffer_end_point = current_record_start;
 		telemetry_buffer_current_position = 0;
+		if (current_record_start == 0) {
+			/* This sample is too large to fit in the buffer even when we started at 0, so skip it */
+			goto cancel_sample;
+		}
 		goto copytobuffer;
 	}
 
@@ -567,6 +584,10 @@ copytobuffer:
 	if ((telemetry_buffer_size - telemetry_buffer_current_position) < uuid_info_array_size) {
 		telemetry_buffer_end_point = current_record_start;
 		telemetry_buffer_current_position = 0;
+		if (current_record_start == 0) {
+			/* This sample is too large to fit in the buffer even when we started at 0, so skip it */
+			goto cancel_sample;
+		}
 		goto copytobuffer;
 	}
 
@@ -588,6 +609,10 @@ copytobuffer:
 		/* wrap and overwrite */
 		telemetry_buffer_end_point = current_record_start;		
 		telemetry_buffer_current_position = 0;
+		if (current_record_start == 0) {
+			/* This sample is too large to fit in the buffer even when we started at 0, so skip it */
+			goto cancel_sample;
+		}
 		goto copytobuffer;
 	}
 
@@ -627,6 +652,10 @@ copytobuffer:
 			/* wrap and overwrite */
 			telemetry_buffer_end_point = current_record_start;		
 			telemetry_buffer_current_position = 0;
+			if (current_record_start == 0) {
+				/* This sample is too large to fit in the buffer even when we started at 0, so skip it */
+				goto cancel_sample;
+			}
 			goto copytobuffer;
 		}
 
@@ -651,6 +680,10 @@ copytobuffer:
 	if ((telemetry_buffer_size - telemetry_buffer_current_position)/framesize < btcount) {
 		telemetry_buffer_end_point = current_record_start;
 		telemetry_buffer_current_position = 0;
+		if (current_record_start == 0) {
+			/* This sample is too large to fit in the buffer even when we started at 0, so skip it */
+			goto cancel_sample;
+		}
 		goto copytobuffer;
 	}
 
@@ -679,6 +712,8 @@ copytobuffer:
 		notify = TRUE;
 	}
 
+cancel_sample:
+
 	TELEMETRY_UNLOCK();
 
 	KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_STACKSHOT, MICROSTACKSHOT_RECORD) | DBG_FUNC_END, notify, telemetry_bytes_since_last_mark, telemetry_buffer_current_position, telemetry_buffer_end_point, 0);