Re: [PATCH v2] smb: client: fix possible double free in smb2_set_ea()

[Dan Carpenter]

On Tue, Oct 15, 2024 at 06:20:37PM +0800, Su Hui wrote:
> Clang static checker(scan-build) warning：
> fs/smb/client/smb2ops.c:1304:2: Attempt to free released memory.
>  1304 |         kfree(ea);
>       |         ^~~~~~~~~
> 
> There is a double free in such case:
> 'ea is initialized to NULL' -> 'first successful memory allocation for
> ea' -> 'something failed, goto sea_exit' -> 'first memory release for ea'
> -> 'goto replay_again' -> 'second goto sea_exit before allocate memory
> for ea' -> 'second memory release for ea resulted in double free'.
> 
> Re-initialie 'ea' to NULL near to the replay_again label, it can fix this
> double free problem.
> 
> Fixes: 4f1fffa23769 ("cifs: commands that are retried should have replay flag set")
> Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx>
> ---
> v2: 
> - Move 'ea = NULL' near to the replay_again label.(Dan's suggestion)

Thanks!

Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

regards,
dan carpenter