From: Wang Yan <wangyan01@kylinos.cn>
To: mic@digikod.net, gnoack@google.com, shuah@kernel.org
Cc: linux-security-module@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Wang Yan <wangyan01@kylinos.cn>,
Haofeng Li <lihaofeng@kylinos.cn>
Subject: [PATCH] selftests/landlock: Fix snprintf truncation checks in test files
Date: Fri, 26 Jun 2026 15:00:16 +0800 [thread overview]
Message-ID: <20260626070016.61049-1-wangyan01@kylinos.cn> (raw)
Commit b566f7a4f0e4 ("selftests/landlock: Fix snprintf truncation checks
in audit helpers") fixed the truncation detection in audit.h by changing
the comparison from ">" to ">=" to correctly handle the edge case where
snprintf returns a value equal to the buffer size.
However, the same pattern exists in ptrace_test.c, audit_test.c, and
net_test.c and was not fixed. snprintf() returns the number of characters
that would have been written, excluding the terminating NUL byte. When
the output is truncated, this return value equals or exceeds the buffer
size. The existing ">" check therefore fails to detect truncation when
the return value equals the buffer size.
Fix these remaining instances to use ">=" for truncation detection,
matching the fix in audit.h.
Fixes: 6a500b22971c ("selftests/landlock: Add tests for audit flags and domain IDs")
Signed-off-by: Haofeng Li <lihaofeng@kylinos.cn>
Signed-off-by: Wang Yan <wangyan01@kylinos.cn>
---
tools/testing/selftests/landlock/audit_test.c | 2 +-
tools/testing/selftests/landlock/net_test.c | 4 ++--
tools/testing/selftests/landlock/ptrace_test.c | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/landlock/audit_test.c b/tools/testing/selftests/landlock/audit_test.c
index 72b5612375dd..4bea8c880a4d 100644
--- a/tools/testing/selftests/landlock/audit_test.c
+++ b/tools/testing/selftests/landlock/audit_test.c
@@ -31,7 +31,7 @@ static int matches_log_signal(struct __test_metadata *const _metadata,
log_match_len =
snprintf(log_match, sizeof(log_match), log_template, opid);
- if (log_match_len > sizeof(log_match))
+ if (log_match_len >= sizeof(log_match))
return -E2BIG;
return audit_match_record(audit_fd, AUDIT_LANDLOCK_ACCESS, log_match,
diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c
index 2ed1f76b7a8b..aebeafd80466 100644
--- a/tools/testing/selftests/landlock/net_test.c
+++ b/tools/testing/selftests/landlock/net_test.c
@@ -2777,7 +2777,7 @@ static int matches_auditlog(const int audit_fd, const char *const blockers,
log_match_len = snprintf(log_match, sizeof(log_match),
log_with_addrport_tmpl, blockers,
dir_addr, addr, dir_port, port);
- if (log_match_len > sizeof(log_match))
+ if (log_match_len >= sizeof(log_match))
return -E2BIG;
return audit_match_record(audit_fd, AUDIT_LANDLOCK_ACCESS, log_match,
@@ -3072,7 +3072,7 @@ static int matches_log_connect_bound(int audit_fd, const char *const blockers,
log_match_len = snprintf(log_match, sizeof(log_match), log_template,
blockers, addr, lport, addr, dport);
- if (log_match_len > sizeof(log_match))
+ if (log_match_len >= sizeof(log_match))
return -E2BIG;
return audit_match_record(audit_fd, AUDIT_LANDLOCK_ACCESS, log_match,
diff --git a/tools/testing/selftests/landlock/ptrace_test.c b/tools/testing/selftests/landlock/ptrace_test.c
index 4f64c90583cd..65cf2d82f721 100644
--- a/tools/testing/selftests/landlock/ptrace_test.c
+++ b/tools/testing/selftests/landlock/ptrace_test.c
@@ -302,7 +302,7 @@ static int matches_log_ptrace(struct __test_metadata *const _metadata,
log_match_len =
snprintf(log_match, sizeof(log_match), log_template, opid);
- if (log_match_len > sizeof(log_match))
+ if (log_match_len >= sizeof(log_match))
return -E2BIG;
return audit_match_record(audit_fd, AUDIT_LANDLOCK_ACCESS, log_match,
--
2.25.1
reply other threads:[~2026-06-26 7:00 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260626070016.61049-1-wangyan01@kylinos.cn \
--to=wangyan01@kylinos.cn \
--cc=gnoack@google.com \
--cc=lihaofeng@kylinos.cn \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=mic@digikod.net \
--cc=shuah@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox