On Mon 08 Jan 2024 at 09:56, Brian Foster <[email protected]>
wrote:
On Sun, Jan 07, 2024 at 03:05:59PM +0800, Su Yue wrote:
The pointer dev_name can be modified by strseq(),
then causes the memleak:
unreferenced object 0xffff9d08a2916c80 (size 32):
comm "mount.bcachefs", pid 9090, jiffies 4295856224 (age
17.564s)
hex dump (first 32 bytes):
2f 64 65 76 2f 6d 61 70 70 65 72 2f 74 65 73 74
/dev/mapper/test
2d 30 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-0..............
backtrace:
[<00000000c5d3be7d>] __kmem_cache_alloc_node+0x1f3/0x2c0
[<0000000052215d26>] __kmalloc_node_track_caller+0x51/0x150
[<0000000069fea956>] kstrdup+0x32/0x60
[<000000000877fcf1>] bch2_split_devs+0x3f/0x150 [bcachefs]
[<000000007ee93204>] bch2_mount+0xcb/0x640 [bcachefs]
[<000000002dd1e04b>] legacy_get_tree+0x30/0x60
[<000000006afc31d3>] vfs_get_tree+0x28/0xf0
[<000000007b0c538e>] path_mount+0x475/0xb60
[<0000000092de5882>] __x64_sys_mount+0x105/0x140
[<0000000054fc05d8>] do_syscall_64+0x42/0xf0
[<00000000df584910>]
entry_SYSCALL_64_after_hwframe+0x6e/0x76
Fix it by copying pointer dev_name at beginning then freeing
the copied
pointer at end.
Signed-off-by: Su Yue <[email protected]>
---
fs/bcachefs/util.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index c2ef7cddaa4f..789953c14f55 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -1186,7 +1186,9 @@ int bch2_split_devs(const char
*_dev_name, darray_str *ret)
{
darray_init(ret);
- char *dev_name = kstrdup(_dev_name, GFP_KERNEL), *s =
dev_name;
+ char *dev_name = kstrdup(_dev_name, GFP_KERNEL);
+ char *s = dev_name, *orig = dev_name;
+
Thanks for the patch. I see this is just moving the assignment
of *s,
but there's no need for that assignment in this code, right? If
not, I
think this would look a little bit cleaner if it fixed that up
as well.
I.e., something like:
Right. v2 sent ;)
--
Su
char *s, *dev_name, *orig;
dev_name = orig = kstrdup(_dev_name, GFP_KERNEL);
if (!dev_name)
return -ENOMEM;
... and then otherwise the rest LGTM.
Brian
@@ -1201,10 +1203,10 @@ int bch2_split_devs(const char
*_dev_name, darray_str *ret)
}
}
- kfree(dev_name);
+ kfree(orig);
return 0;
err:
bch2_darray_str_exit(ret);
- kfree(dev_name);
+ kfree(orig);
return -ENOMEM;
}
--
2.43.0
