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Subject[PATCH 2/6] afs: Do better max capacity handling on address lists
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Note the maximum allocated capacity in an afs_addr_list struct and discard
addresses that would exceed it in afs_merge_fs_addr{4,6}().

Also, since the current maximum capacity is less than 255, reduce the
relevant members to bytes.

Signed-off-by: David Howells <dhowells@redhat.com>
---

fs/afs/addr_list.c | 19 +++++++++++--------
fs/afs/internal.h | 8 +++++---
2 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
index 025a9a5e1c32..4dbb8af54668 100644
--- a/fs/afs/addr_list.c
+++ b/fs/afs/addr_list.c
@@ -17,11 +17,6 @@
#include "internal.h"
#include "afs_fs.h"

-//#define AFS_MAX_ADDRESSES
-// ((unsigned int)((PAGE_SIZE - sizeof(struct afs_addr_list)) /
-// sizeof(struct sockaddr_rxrpc)))
-#define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
-
/*
* Release an address list.
*/
@@ -43,11 +38,15 @@ struct afs_addr_list *afs_alloc_addrlist(unsigned int nr,

_enter("%u,%u,%u", nr, service, port);

+ if (nr > AFS_MAX_ADDRESSES)
+ nr = AFS_MAX_ADDRESSES;
+
alist = kzalloc(struct_size(alist, addrs, nr), GFP_KERNEL);
if (!alist)
return NULL;

refcount_set(&alist->usage, 1);
+ alist->max_addrs = nr;

for (i = 0; i < nr; i++) {
struct sockaddr_rxrpc *srx = &alist->addrs[i];
@@ -109,8 +108,6 @@ struct afs_addr_list *afs_parse_text_addrs(const char *text, size_t len,
} while (p < end);

_debug("%u/%u addresses", nr, AFS_MAX_ADDRESSES);
- if (nr > AFS_MAX_ADDRESSES)
- nr = AFS_MAX_ADDRESSES;

alist = afs_alloc_addrlist(nr, service, port);
if (!alist)
@@ -180,7 +177,7 @@ struct afs_addr_list *afs_parse_text_addrs(const char *text, size_t len,
}

alist->nr_addrs++;
- } while (p < end && alist->nr_addrs < AFS_MAX_ADDRESSES);
+ } while (p < end && alist->nr_addrs < alist->max_addrs);

_leave(" = [nr %u]", alist->nr_addrs);
return alist;
@@ -241,6 +238,9 @@ void afs_merge_fs_addr4(struct afs_addr_list *alist, __be32 xdr, u16 port)
__be16 xport = htons(port);
int i;

+ if (alist->nr_addrs >= alist->max_addrs)
+ return;
+
for (i = 0; i < alist->nr_ipv4; i++) {
a = &alist->addrs[i].transport.sin6;
if (xdr == a->sin6_addr.s6_addr32[3] &&
@@ -277,6 +277,9 @@ void afs_merge_fs_addr6(struct afs_addr_list *alist, __be32 *xdr, u16 port)
__be16 xport = htons(port);
int i, diff;

+ if (alist->nr_addrs >= alist->max_addrs)
+ return;
+
for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
a = &alist->addrs[i].transport.sin6;
diff = memcmp(xdr, &a->sin6_addr, 16);
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 871a228d7f37..8ae4e2ebb99a 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -73,12 +73,14 @@ struct afs_addr_list {
struct rcu_head rcu; /* Must be first */
refcount_t usage;
u32 version; /* Version */
- unsigned short nr_addrs;
- unsigned short index; /* Address currently in use */
- unsigned short nr_ipv4; /* Number of IPv4 addresses */
+ unsigned char max_addrs;
+ unsigned char nr_addrs;
+ unsigned char index; /* Address currently in use */
+ unsigned char nr_ipv4; /* Number of IPv4 addresses */
unsigned long probed; /* Mask of servers that have been probed */
unsigned long yfs; /* Mask of servers that are YFS */
struct sockaddr_rxrpc addrs[];
+#define AFS_MAX_ADDRESSES ((unsigned int)(sizeof(unsigned long) * 8))
};

/*
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