From e92eebb0d6116f942ab25dfb1a41905aa59472a8 Mon Sep 17 00:00:00 2001 From: Ricardo Robaina Date: Fri, 22 Nov 2024 09:18:43 -0300 Subject: [PATCH] audit: fix suffixed '/' filename matching When the user specifies a directory to delete with the suffix '/', the audit record fails to collect the filename, resulting in the following logs: type=PATH msg=audit(10/30/2024 14:11:17.796:6304) : item=2 name=(null) type=PATH msg=audit(10/30/2024 14:11:17.796:6304) : item=1 name=(null) It happens because the value of the variables dname, and n->name->name in __audit_inode_child() differ only by the suffix '/'. This commit treats this corner case by handling pathname's trailing slashes in audit_compare_dname_path(). Steps to reproduce the issue: # auditctl -w /tmp $ mkdir /tmp/foo $ rm -r /tmp/foo/ # ausearch -i | grep PATH | tail -3 The first version of this patch was based on a GitHub patch/PR by user @hqh2010 [1]. Link: https://github.com/linux-audit/audit-kernel/pull/148 [1] Suggested-by: Paul Moore Signed-off-by: Ricardo Robaina Reviewed-by: Richard Guy Briggs [PM: subject tweak, trim old metadata] Signed-off-by: Paul Moore --- kernel/auditfilter.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index bceb9f58a09e..e3f42018ed46 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -1319,13 +1319,20 @@ int audit_compare_dname_path(const struct qstr *dname, const char *path, int par if (pathlen < dlen) return 1; - parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen; - if (pathlen - parentlen != dlen) - return 1; + if (parentlen == AUDIT_NAME_FULL) + parentlen = parent_len(path); p = path + parentlen; - return strncmp(p, dname->name, dlen); + /* handle trailing slashes */ + pathlen -= parentlen; + while (p[pathlen - 1] == '/') + pathlen--; + + if (pathlen != dlen) + return 1; + + return memcmp(p, dname->name, dlen); } int audit_filter(int msgtype, unsigned int listtype)