Upstream-Status: Backport Signed-off-by: Ross Burton From b0422e9e5a539164af75cddcaeb01bceca56bf12 Mon Sep 17 00:00:00 2001 From: "Frank Ch. Eigler" Date: Thu, 13 Jan 2022 18:33:15 -0500 Subject: [PATCH] PR28778: gcc warning tweak for sprintf precision parameter A precision=-1 sentinel value got interpreted as UINT_MAX in a context, leading to diagnostics like: /usr/share/systemtap/runtime/vsprintf.c:341:23: error: 'strnlen' specified bound 4294967295 may exceed maximum object size 2147483647 [-Werror=stringop-overread] Adding a clamp_t() around the parameter field to keep it limited to STP_BUFFER_SIZE (8K by default), which is apprx. the limit for a single printf. --- runtime/vsprintf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/runtime/vsprintf.c b/runtime/vsprintf.c index cd31a938b..606f685e8 100644 --- a/runtime/vsprintf.c +++ b/runtime/vsprintf.c @@ -338,7 +338,7 @@ _stp_vsprint_memory(char * str, char * end, const char * ptr, if (format == 's') { if ((unsigned long)ptr < PAGE_SIZE) ptr = ""; - len = strnlen(ptr, precision); + len = strnlen(ptr, clamp_t(size_t, precision, 0, STP_BUFFER_SIZE)); } else if (precision > 0) len = precision; @@ -410,7 +410,7 @@ _stp_vsprint_memory_size(const char * ptr, int width, int precision, if (format == 's') { if ((unsigned long)ptr < PAGE_SIZE) ptr = ""; - len = strnlen(ptr, precision); + len = strnlen(ptr, clamp_t(size_t, precision, 0, STP_BUFFER_SIZE)); } else if (precision > 0) len = precision; -- 2.25.1