From: Stanislav Fort Date: Tue, 2 Sep 2025 11:00:49 +0000 (+0300) Subject: audit: fix out-of-bounds read in audit_compare_dname_path() X-Git-Tag: v6.17-rc5~12^2 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=4540f1d23e7f387880ce46d11b5cd3f27248bf8d;p=users%2Fgriffoul%2Flinux.git audit: fix out-of-bounds read in audit_compare_dname_path() When a watch on dir=/ is combined with an fsnotify event for a single-character name directly under / (e.g., creating /a), an out-of-bounds read can occur in audit_compare_dname_path(). The helper parent_len() returns 1 for "/". In audit_compare_dname_path(), when parentlen equals the full path length (1), the code sets p = path + 1 and pathlen = 1 - 1 = 0. The subsequent loop then dereferences p[pathlen - 1] (i.e., p[-1]), causing an out-of-bounds read. Fix this by adding a pathlen > 0 check to the while loop condition to prevent the out-of-bounds access. Cc: stable@vger.kernel.org Fixes: e92eebb0d611 ("audit: fix suffixed '/' filename matching") Reported-by: Stanislav Fort Suggested-by: Linus Torvalds Signed-off-by: Stanislav Fort [PM: subject tweak, sign-off email fixes] Signed-off-by: Paul Moore --- diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index e3f42018ed46..f7708fe2c457 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -1326,7 +1326,7 @@ int audit_compare_dname_path(const struct qstr *dname, const char *path, int par /* handle trailing slashes */ pathlen -= parentlen; - while (p[pathlen - 1] == '/') + while (pathlen > 0 && p[pathlen - 1] == '/') pathlen--; if (pathlen != dlen)