afs: Do better max capacity handling on address lists

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>

diff --git a/fs/afs/addr_list.c b/fs/afs/addr_list.c
index 025a9a5e1c32c29c4daf3cd40aba8537475af250..4dbb8af546686baf9cd1c4aa7089ef9a41cebc5c 100644 (file)
--- 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 871a228d7f37ce1b0b0d7122b41a8f83f134f391..8ae4e2ebb99a5bf063a059f82476f5bf2dac50e2 100644 (file)
--- 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))
 };
 
 /*