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.
Reported-by: Stanislav Fort <disclos...@aisle.com>
Suggested-by: Linus Torvalds <torva...@linuxfoundation.org>
Signed-off-by: Stanislav Fort <disclos...@aisle.com>
---
kernel/auditfilter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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)
--
2.39.3 (Apple Git-146)
