From: Karel Zak <kzak@redhat.com>
Date: Mon, 26 Feb 2024 13:30:55 +0000 (+0100)
Subject: dmesg: fix wrong size calculation
X-Git-Tag: v2.40-rc2~24
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0e78f7c1b25e0390befe0c1d252420dab44b3488;p=thirdparty%2Futil-linux.git

dmesg: fix wrong size calculation

* don't use string based function strspn() if work with non-zero terminated
  buffer

* make sure that message size is calculated from within buffer pointers

Fixes: https://github.com/util-linux/util-linux/issues/2807
Signed-off-by: Karel Zak <kzak@redhat.com>
(cherry picked from commit 0e5031a425c727b16831c108a92271e240c29595)
---

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index 48282f1e6..25c674be3 100644
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -939,13 +939,17 @@ static int get_next_syslog_record(struct dmesg_control *ctl,
 			const char *start = begin + 1;
 			size_t id_size;
 
-			start = start + strspn(start, " ");
+			while (start < end && *start == ' ')
+				start++;
+
 			begin = skip_item(begin, end, "]");
 			id_size = begin - start;
+
 			if (id_size < sizeof(rec->caller_id))
 				xstrncpy(rec->caller_id, start, id_size);
-			rec->mesg = begin + 1;
-			rec->mesg_size = end - begin - 1;
+
+			rec->mesg = begin < end ? begin + 1 : NULL;
+			rec->mesg_size = begin < end ? end - begin - 1 : 0;
 		} else {
 			rec->mesg = begin;
 			rec->mesg_size = end - begin;