9d52865ff2
[ Upstream commit 251a658bbfceafb4d58c76b77682c8bf7bcfad65 ] A call to listxattr() with a buffer size = 0 returns the actual size of the buffer needed for a subsequent call. When size > 0, nfs4_listxattr() does not return an error because either generic_listxattr() or nfs4_listxattr_nfs4_label() consumes exactly all the bytes then size is 0 when calling nfs4_listxattr_nfs4_user() which then triggers the following kernel BUG: [ 99.403778] kernel BUG at mm/usercopy.c:102! [ 99.404063] Internal error: Oops - BUG: 00000000f2000800 [#1] SMP [ 99.408463] CPU: 0 PID: 3310 Comm: python3 Not tainted 6.6.0-61.fc40.aarch64 #1 [ 99.415827] Call trace: [ 99.415985] usercopy_abort+0x70/0xa0 [ 99.416227] __check_heap_object+0x134/0x158 [ 99.416505] check_heap_object+0x150/0x188 [ 99.416696] __check_object_size.part.0+0x78/0x168 [ 99.416886] __check_object_size+0x28/0x40 [ 99.417078] listxattr+0x8c/0x120 [ 99.417252] path_listxattr+0x78/0xe0 [ 99.417476] __arm64_sys_listxattr+0x28/0x40 [ 99.417723] invoke_syscall+0x78/0x100 [ 99.417929] el0_svc_common.constprop.0+0x48/0xf0 [ 99.418186] do_el0_svc+0x24/0x38 [ 99.418376] el0_svc+0x3c/0x110 [ 99.418554] el0t_64_sync_handler+0x120/0x130 [ 99.418788] el0t_64_sync+0x194/0x198 [ 99.418994] Code: aa0003e3 d000a3e0 91310000 97f49bdb (d4210000) Issue is reproduced when generic_listxattr() returns 'system.nfs4_acl', thus calling lisxattr() with size = 16 will trigger the bug. Add check on nfs4_listxattr() to return ERANGE error when it is called with size > 0 and the return value is greater than size. Fixes: 012a211abd5d ("NFSv4.2: hook in the user extended attribute handlers") Signed-off-by: Jorge Mora <mora@netapp.com> Reviewed-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.