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Commit faa0935f authored by Narayan Kamath's avatar Narayan Kamath
Browse files

sdcard : inode numbers must be fully representable as uint32_t. 

This works around a bug on on 64 bit kernels + sdcard daemons
where we were using memory addresses as inode numbers.

bug: 19012244

Change-Id: Ia63c5b33b4212bf03ff92fa2faff0bb76e48791c
parent f2bd3fdd

sdcard/sdcard.c

+34 −1
Original line number Diff line number Diff line
@@ -168,6 +168,11 @@ struct node { 
    __u32 refcount;

    __u64 nid;

    __u64 gen;

    /*

     * The inode number for this FUSE node. Note that this isn't stable across

     * multiple invocations of the FUSE daemon.

     */

    __u32 ino;



    /* State derived based on current position in hierarchy. */

    perm_t perm;
@@ -224,6 +229,25 @@ struct fuse { 
    struct node root;

    char obbpath[PATH_MAX];



    /* Used to allocate unique inode numbers for fuse nodes. We use

     * a simple counter based scheme where inode numbers from deleted

     * nodes aren't reused. Note that inode allocations are not stable

     * across multiple invocation of the sdcard daemon, but that shouldn't

     * be a huge problem in practice.

     *

     * Note that we restrict inodes to 32 bit unsigned integers to prevent

     * truncation on 32 bit processes when unsigned long long stat.st_ino is

     * assigned to an unsigned long ino_t type in an LP32 process.

     *

     * Also note that fuse_attr and fuse_dirent inode values are 64 bits wide

     * on both LP32 and LP64, but the fuse kernel code doesn't squash 64 bit

     * inode numbers into 32 bit values on 64 bit kernels (see fuse_squash_ino

     * in fs/fuse/inode.c).

     *

     * Accesses must be guarded by |lock|.

     */

    __u32 inode_ctr;



    Hashmap* package_to_appid;

    Hashmap* appid_with_rw;

};
@@ -387,7 +411,7 @@ static char* find_file_within(const char* path, const char* name, 


static void attr_from_stat(struct fuse_attr *attr, const struct stat *s, const struct node* node)

{

    attr->ino = node->nid;

    attr->ino = node->ino;

    attr->size = s->st_size;

    attr->blocks = s->st_blocks;

    attr->atime = s->st_atime;
@@ -575,6 +599,13 @@ struct node *create_node_locked(struct fuse* fuse, 
    struct node *node;

    size_t namelen = strlen(name);



    // Detect overflows in the inode counter. "4 billion nodes should be enough

    // for everybody".

    if (fuse->inode_ctr == 0) {

        ERROR("No more inode numbers available");

        return NULL;

    }



    node = calloc(1, sizeof(struct node));

    if (!node) {

        return NULL;
@@ -596,6 +627,7 @@ struct node *create_node_locked(struct fuse* fuse, 
    }

    node->namelen = namelen;

    node->nid = ptr_to_id(node);

    node->ino = fuse->inode_ctr++;

    node->gen = fuse->next_generation++;



    derive_permissions_locked(fuse, parent, node);
@@ -700,6 +732,7 @@ static void fuse_init(struct fuse *fuse, int fd, const char *source_path, 
    fuse->derive = derive;

    fuse->split_perms = split_perms;

    fuse->write_gid = write_gid;

    fuse->inode_ctr = 1;



    memset(&fuse->root, 0, sizeof(fuse->root));

    fuse->root.nid = FUSE_ROOT_ID; /* 1 */