[PATCH 5.7 178/265] afs: Fix storage of cell names

Sasha Levin
2020-06-29T21:51:49Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit 719fdd32921fb7e3208db8832d32ae1c2d68900f ]

The cell name stored in the afs_cell struct is a 64-char + NUL buffer -
when it needs to be able to handle up to AFS_MAXCELLNAME (256 chars) + NUL.

Fix this by changing the array to a pointer and allocating the string.

Found using Coverity.

Fixes: 989782dcdc91 ("afs: Overhaul cell database management")
Reported-by: Colin Ian King <colin.king@canonical.com>
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/cell.c | 9 +++++++++
fs/afs/internal.h | 2 +-
2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/afs/cell.c b/fs/afs/cell.c
index 78ba5f9322879..296b489861a9a 100644
--- a/fs/afs/cell.c
+++ b/fs/afs/cell.c
@@ -154,10 +154,17 @@ static struct afs_cell *afs_alloc_cell(struct afs_net *net,
return ERR_PTR(-ENOMEM);
}

+ cell->name = kmalloc(namelen + 1, GFP_KERNEL);
+ if (!cell->name) {
+ kfree(cell);
+ return ERR_PTR(-ENOMEM);
+ }
+
cell->net = net;
cell->name_len = namelen;
for (i = 0; i < namelen; i++)
cell->name[i] = tolower(name[i]);
+ cell->name[i] = 0;

atomic_set(&cell->usage, 2);
INIT_WORK(&cell->manager, afs_manage_cell);
@@ -203,6 +210,7 @@ parse_failed:
if (ret == -EINVAL)
printk(KERN_ERR "kAFS: bad VL server IP address\n");
error:
+ kfree(cell->name);
kfree(cell);
_leave(" = %d", ret);
return ERR_PTR(ret);
@@ -483,6 +491,7 @@ static void afs_cell_destroy(struct rcu_head *rcu)

afs_put_vlserverlist(cell->net, rcu_access_pointer(cell->vl_servers));
key_put(cell->anonymous_key);
+ kfree(cell->name);
kfree(cell);

_leave(" [destroyed]");
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 98e0cebd5e5e9..c67a9767397d0 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -397,7 +397,7 @@ struct afs_cell {
struct afs_vlserver_list __rcu *vl_servers;

u8 name_len; /* Length of name */
- char name[64 + 1]; /* Cell name, case-flattened and NUL-padded */
+ char *name; /* Cell name, case-flattened and NUL-padded */
};

/*
--
2.25.1