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authorJorge Mora <jmora1300@gmail.com>2024-01-25 07:56:12 -0700
committerTrond Myklebust <trond.myklebust@hammerspace.com>2024-02-28 16:18:18 -0500
commit251a658bbfceafb4d58c76b77682c8bf7bcfad65 (patch)
tree52509a73f240747ffa950b47bad58a0605f9dcb8 /fs/nfs/nfs4proc.c
parent490566edad2309f1fe086887efa311fdf65b4a04 (diff)
NFSv4.2: fix nfs4_listxattr kernel BUG at mm/usercopy.c:102
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>
Diffstat (limited to 'fs/nfs/nfs4proc.c')
-rw-r--r--fs/nfs/nfs4proc.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 23819a756508..b2ff8c7a2149 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -10615,29 +10615,33 @@ const struct nfs4_minor_version_ops *nfs_v4_minor_ops[] = {
static ssize_t nfs4_listxattr(struct dentry *dentry, char *list, size_t size)
{
ssize_t error, error2, error3;
+ size_t left = size;
- error = generic_listxattr(dentry, list, size);
+ error = generic_listxattr(dentry, list, left);
if (error < 0)
return error;
if (list) {
list += error;
- size -= error;
+ left -= error;
}
- error2 = nfs4_listxattr_nfs4_label(d_inode(dentry), list, size);
+ error2 = nfs4_listxattr_nfs4_label(d_inode(dentry), list, left);
if (error2 < 0)
return error2;
if (list) {
list += error2;
- size -= error2;
+ left -= error2;
}
- error3 = nfs4_listxattr_nfs4_user(d_inode(dentry), list, size);
+ error3 = nfs4_listxattr_nfs4_user(d_inode(dentry), list, left);
if (error3 < 0)
return error3;
- return error + error2 + error3;
+ error += error2 + error3;
+ if (size && error > size)
+ return -ERANGE;
+ return error;
}
static void nfs4_enable_swap(struct inode *inode)