hfs/hfsplus: fix slab-out-of-bounds in hfs_bnode_read_key

commit bb5e07cb927724e0b47be371fa081141cfb14414 upstream.

Syzbot reported an issue in hfs subsystem:

BUG: KASAN: slab-out-of-bounds in memcpy_from_page include/linux/highmem.h:423 [inline]
BUG: KASAN: slab-out-of-bounds in hfs_bnode_read fs/hfs/bnode.c:35 [inline]
BUG: KASAN: slab-out-of-bounds in hfs_bnode_read_key+0x314/0x450 fs/hfs/bnode.c:70
Write of size 94 at addr ffff8880123cd100 by task syz-executor237/5102

Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189
 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106
 memcpy_from_page include/linux/highmem.h:423 [inline]
 hfs_bnode_read fs/hfs/bnode.c:35 [inline]
 hfs_bnode_read_key+0x314/0x450 fs/hfs/bnode.c:70
 hfs_brec_insert+0x7f3/0xbd0 fs/hfs/brec.c:159
 hfs_cat_create+0x41d/0xa50 fs/hfs/catalog.c:118
 hfs_mkdir+0x6c/0xe0 fs/hfs/dir.c:232
 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
 do_mkdirat+0x264/0x3a0 fs/namei.c:4280
 __do_sys_mkdir fs/namei.c:4300 [inline]
 __se_sys_mkdir fs/namei.c:4298 [inline]
 __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4298
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbdd6057a99

Add a check for key length in hfs_bnode_read_key to prevent
out-of-bounds memory access. If the key length is invalid, the
key buffer is cleared, improving stability and reliability.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+5f3a973ed3dfb85a6683@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=5f3a973ed3dfb85a6683
Cc: stable@vger.kernel.org
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Link: https://lore.kernel.org/20241019191303.24048-1-kovalev@altlinux.org
Reviewed-by: Cengiz Can <cengiz.can@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c
index 6add6ebfef89678d95d95d239a4f23dc8e4b3af5..cb823a8a6ba96099c11b59a4fe88c9b465e2958e 100644 (file)
--- a/fs/hfs/bnode.c
+++ b/fs/hfs/bnode.c
@@ -67,6 +67,12 @@ void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
        else
                key_len = tree->max_key_len + 1;
 
+       if (key_len > sizeof(hfs_btree_key) || key_len < 1) {
+               memset(key, 0, sizeof(hfs_btree_key));
+               pr_err("hfs: Invalid key length: %d\n", key_len);
+               return;
+       }
+
        hfs_bnode_read(node, key, off, key_len);
 }
 

diff --git a/fs/hfsplus/bnode.c b/fs/hfsplus/bnode.c
index 87974d5e679156c63809dbae93ddcf32e1e9ab18..079ea80534f7de0152410af0e0101428e7c9a17a 100644 (file)
--- a/fs/hfsplus/bnode.c
+++ b/fs/hfsplus/bnode.c
@@ -67,6 +67,12 @@ void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
        else
                key_len = tree->max_key_len + 2;
 
+       if (key_len > sizeof(hfsplus_btree_key) || key_len < 1) {
+               memset(key, 0, sizeof(hfsplus_btree_key));
+               pr_err("hfsplus: Invalid key length: %d\n", key_len);
+               return;
+       }
+
        hfs_bnode_read(node, key, off, key_len);
 }