From 101673ea9282a32b1e01a976623083ac06cfc04b Mon Sep 17 00:00:00 2001 From: Ritesh Harjani Date: Mon, 19 Mar 2018 15:49:54 +0530 Subject: [PATCH] ANDROID: sdcardfs: Fix sdcardfs to stop creating cases-sensitive duplicate entries. sdcardfs_name_match gets a 'name' argument from the underlying FS. This need not be null terminated string. So in sdcardfs_name_match -> qstr_case_eq -> we should use str_n_case_eq. This happens because few of the entries in lower level FS may not be NULL terminated and may have some garbage characters passed while doing sdcardfs_name_match. For e.g. # dmesg |grep Download [ 103.646386] sdcardfs_name_match: q1->name=.nomedia, q1->len=8, q2->name=Download\x17\x80\x03, q2->len=8 [ 104.021340] sdcardfs_name_match: q1->name=.nomedia, q1->len=8, q2->name=Download\x17\x80\x03, q2->len=8 [ 105.196864] sdcardfs_name_match: q1->name=.nomedia, q1->len=8, q2->name=Download\x17\x80\x03, q2->len=8 [ 109.113521] sdcardfs_name_match: q1->name=logs, q1->len=4, q2->name=Download\x17\x80\x03, q2->len=8 Now when we try to create a directory with different case for a such files. SDCARDFS creates a entry if it could not find the underlying entry in it's dcache. To reproduce:- 1. bootup the device wait for some time after sdcardfs mounting to complete. 2. cd /storage/emulated/0 3. echo 3 > /proc/sys/vm/drop_caches 4. mkdir download We now start seeing two entries with name. Download & download. Change-Id: I976d92a220a607dd8cdb96c01c2041c5c2bc3326 Signed-off-by: Ritesh Harjani bug: 75987238 --- fs/sdcardfs/sdcardfs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h index 610466ad153d..826afb5c7e88 100644 --- a/fs/sdcardfs/sdcardfs.h +++ b/fs/sdcardfs/sdcardfs.h @@ -669,7 +669,7 @@ static inline bool str_n_case_eq(const char *s1, const char *s2, size_t len) static inline bool qstr_case_eq(const struct qstr *q1, const struct qstr *q2) { - return q1->len == q2->len && str_case_eq(q1->name, q2->name); + return q1->len == q2->len && str_n_case_eq(q1->name, q2->name, q2->len); } #define QSTR_LITERAL(string) QSTR_INIT(string, sizeof(string)-1)