[PATCH] tracing: use correct string size for snprintf
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From: Chase Douglas on 15 Jun 2010 12:30 The nsecs_str string is a local variable defined as: char nsecs_str[5]; It is possible for the snprintf call to use a size value larger than the size of the string. This should not cause a buffer overrun as it is written now due to the maximum size of the string format. However, this change makes it correct. By making the size correct we guard against potential future changes that could actually cause a buffer overrun. Cc: stable(a)kernel.org Signed-off-by: Chase Douglas <chase.douglas(a)canonical.com> --- kernel/trace/trace_functions_graph.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 79f4bac..73d6bd1 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -641,7 +641,8 @@ trace_print_graph_duration(unsigned long long duration, struct trace_seq *s) /* Print nsecs (we don't want to exceed 7 numbers) */ if (len < 7) { - snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem); + snprintf(nsecs_str, min(sizeof(nsecs_str), 8 - len), "%03lu", + nsecs_rem); ret = trace_seq_printf(s, ".%s", nsecs_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |