| Upstream-Status: Backport |
| Signed-off-by: Ross Burton <ross.burton@arm.com> |
| |
| From b0422e9e5a539164af75cddcaeb01bceca56bf12 Mon Sep 17 00:00:00 2001 |
| From: "Frank Ch. Eigler" <fche@redhat.com> |
| 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 = "<NULL>"; |
| - 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 = "<NULL>"; |
| - 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 |
| |