[PATCH 5.9 043/255] afs: Fix incorrect freeing of the ACL passed to the YFS ACL store op

Greg Kroah-Hartman
2020-11-17T13:32:40Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit f4c79144edd8a49ffca8fa737a31d606be742a34 ]

The cleanup for the yfs_store_opaque_acl2_operation calls the wrong
function to destroy the ACL content buffer. It's an afs_acl struct, not
a yfs_acl struct - and the free function for latter may pass invalid
pointers to kfree().

Fix this by using the afs_acl_put() function. The yfs_acl_put()
function is then no longer used and can be removed.

general protection fault, probably for non-canonical address 0x7ebde00000000: 0000 [#1] SMP PTI
...
RIP: 0010:compound_head+0x0/0x11
...
Call Trace:
virt_to_cache+0x8/0x51
kfree+0x5d/0x79
yfs_free_opaque_acl+0x16/0x29
afs_put_operation+0x60/0x114
__vfs_setxattr+0x67/0x72
__vfs_setxattr_noperm+0x66/0xe9
vfs_setxattr+0x67/0xce
setxattr+0x14e/0x184
__do_sys_fsetxattr+0x66/0x8f
do_syscall_64+0x2d/0x3a
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/afs/xattr.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c
index 38884d6c57cdc..95c573dcda116 100644
--- a/fs/afs/xattr.c
+++ b/fs/afs/xattr.c
@@ -148,11 +148,6 @@ static const struct xattr_handler afs_xattr_afs_acl_handler = {
.set = afs_xattr_set_acl,
};

-static void yfs_acl_put(struct afs_operation *op)
-{
- yfs_free_opaque_acl(op->yacl);
-}
-
static const struct afs_operation_ops yfs_fetch_opaque_acl_operation = {
.issue_yfs_rpc = yfs_fs_fetch_opaque_acl,
.success = afs_acl_success,
@@ -246,7 +241,7 @@ error:
static const struct afs_operation_ops yfs_store_opaque_acl2_operation = {
.issue_yfs_rpc = yfs_fs_store_opaque_acl2,
.success = afs_acl_success,
- .put = yfs_acl_put,
+ .put = afs_acl_put,
};

/*
--
2.27.0