| Andrew Geissler | 595f630 | 2022-01-24 19:11:47 +0000 | [diff] [blame] | 1 | Upstream-Status: Backport |
| 2 | Signed-off-by: Ross Burton <ross.burton@arm.com> |
| 3 | |
| 4 | From b0422e9e5a539164af75cddcaeb01bceca56bf12 Mon Sep 17 00:00:00 2001 |
| 5 | From: "Frank Ch. Eigler" <fche@redhat.com> |
| 6 | Date: Thu, 13 Jan 2022 18:33:15 -0500 |
| 7 | Subject: [PATCH] PR28778: gcc warning tweak for sprintf precision parameter |
| 8 | |
| 9 | A precision=-1 sentinel value got interpreted as UINT_MAX in a |
| 10 | context, leading to diagnostics like: |
| 11 | |
| 12 | /usr/share/systemtap/runtime/vsprintf.c:341:23: error: 'strnlen' specified bound 4294967295 may exceed maximum object size 2147483647 [-Werror=stringop-overread] |
| 13 | |
| 14 | Adding a clamp_t() around the parameter field to keep it limited to |
| 15 | STP_BUFFER_SIZE (8K by default), which is apprx. the limit for a |
| 16 | single printf. |
| 17 | --- |
| 18 | runtime/vsprintf.c | 4 ++-- |
| 19 | 1 file changed, 2 insertions(+), 2 deletions(-) |
| 20 | |
| 21 | diff --git a/runtime/vsprintf.c b/runtime/vsprintf.c |
| 22 | index cd31a938b..606f685e8 100644 |
| 23 | --- a/runtime/vsprintf.c |
| 24 | +++ b/runtime/vsprintf.c |
| 25 | @@ -338,7 +338,7 @@ _stp_vsprint_memory(char * str, char * end, const char * ptr, |
| 26 | if (format == 's') { |
| 27 | if ((unsigned long)ptr < PAGE_SIZE) |
| 28 | ptr = "<NULL>"; |
| 29 | - len = strnlen(ptr, precision); |
| 30 | + len = strnlen(ptr, clamp_t(size_t, precision, 0, STP_BUFFER_SIZE)); |
| 31 | } |
| 32 | else if (precision > 0) |
| 33 | len = precision; |
| 34 | @@ -410,7 +410,7 @@ _stp_vsprint_memory_size(const char * ptr, int width, int precision, |
| 35 | if (format == 's') { |
| 36 | if ((unsigned long)ptr < PAGE_SIZE) |
| 37 | ptr = "<NULL>"; |
| 38 | - len = strnlen(ptr, precision); |
| 39 | + len = strnlen(ptr, clamp_t(size_t, precision, 0, STP_BUFFER_SIZE)); |
| 40 | } |
| 41 | else if (precision > 0) |
| 42 | len = precision; |
| 43 | -- |
| 44 | 2.25.1 |
| 45 | |