[PATCH 8/9] tracing/function-graph: Use correct string size for snprintf
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From: Steven Rostedt on 28 Jun 2010 23:20 From: Chase Douglas <chase.douglas(a)canonical.com> 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 value for the string format "%03lu" can not be larger than 1000. However, this change makes it correct. By making the size correct we guard against potential future changes that could actually cause a buffer overrun. Signed-off-by: Chase Douglas <chase.douglas(a)canonical.com> LKML-Reference: <1276619355-18116-1-git-send-email-chase.douglas(a)canonical.com> [ added 'UL' to number 8 to fix gcc warning comparing it to sizeof() ] Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org> --- 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..6bff236 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), 8UL - len), "%03lu", + nsecs_rem); ret = trace_seq_printf(s, ".%s", nsecs_str); if (!ret) return TRACE_TYPE_PARTIAL_LINE; -- 1.7.1 -- 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/ |