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authorEdward Adam Davis <eadavis@qq.com>2024-04-11 15:05:28 +0300
committerDave Kleikamp <dave.kleikamp@oracle.com>2024-06-26 20:27:33 +0300
commitce6dede912f064a855acf6f04a04cbb2c25b8c8c (patch)
treea0cbdffb4d8447ebfcf5a3e4b48874e926983f0d /fs/jfs
parentee6817e72d4e690b65ce0f77f406ed1a1ac5b5c2 (diff)
downloadlinux-ce6dede912f064a855acf6f04a04cbb2c25b8c8c.tar.xz
jfs: fix null ptr deref in dtInsertEntry
[syzbot reported] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 5061 Comm: syz-executor404 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 RIP: 0010:dtInsertEntry+0xd0c/0x1780 fs/jfs/jfs_dtree.c:3713 ... [Analyze] In dtInsertEntry(), when the pointer h has the same value as p, after writing name in UniStrncpy_to_le(), p->header.flag will be cleared. This will cause the previously true judgment "p->header.flag & BT-LEAF" to change to no after writing the name operation, this leads to entering an incorrect branch and accessing the uninitialized object ih when judging this condition for the second time. [Fix] After got the page, check freelist first, if freelist == 0 then exit dtInsert() and return -EINVAL. Reported-by: syzbot+bba84aef3a26fb93deb9@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis <eadavis@qq.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Diffstat (limited to 'fs/jfs')
-rw-r--r--fs/jfs/jfs_dtree.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 031d8f570f58..5d3127ca68a4 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -834,6 +834,8 @@ int dtInsert(tid_t tid, struct inode *ip,
* the full page.
*/
DT_GETSEARCH(ip, btstack->top, bn, mp, p, index);
+ if (p->header.freelist == 0)
+ return -EINVAL;
/*
* insert entry for new key