ext4: no need to continue when the number of entries is 1
commit 1a00a393d6a7fb1e745a41edd09019bd6a0ad64c upstream.
BUG=b/377000712
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-49967 in the Linux kernel.
cos-patch: security-high
Fixes: ac27a0ec112a ("[PATCH] ext4: initial copy of files from ext3")
Reported-by: syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ae688d469e36fb5138d0
Change-Id: I3b82fce6b31946f35dd6e16cee8dd99fca89e970
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Reported-and-tested-by: syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com
Link: https://patch.msgid.link/tencent_BE7AEE6C7C2D216CB8949CE8E6EE7ECC2C0A@qq.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/85171
Reviewed-by: Anil Altinay <aaltinay@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Kevin Berry <kpberry@google.com>
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 173f46f..56a79cd3 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2045,7 +2045,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
split = count/2;
hash2 = map[split].hash;
- continued = hash2 == map[split - 1].hash;
+ continued = split > 0 ? hash2 == map[split - 1].hash : 0;
dxtrace(printk(KERN_INFO "Split block %lu at %x, %i/%i\n",
(unsigned long)dx_get_block(frame->at),
hash2, split, count-split));
