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    Subject[PATCH 5.9 215/391] fs/kernel_read_file: Remove FIRMWARE_PREALLOC_BUFFER enum
    Date
    From: Kees Cook <keescook@chromium.org>

    commit c307459b9d1fcb8bbf3ea5a4162979532322ef77 upstream.

    FIRMWARE_PREALLOC_BUFFER is a "how", not a "what", and confuses the LSMs
    that are interested in filtering between types of things. The "how"
    should be an internal detail made uninteresting to the LSMs.

    Fixes: a098ecd2fa7d ("firmware: support loading into a pre-allocated buffer")
    Fixes: fd90bc559bfb ("ima: based on policy verify firmware signatures (pre-allocated buffer)")
    Fixes: 4f0496d8ffa3 ("ima: based on policy warn about loading firmware (pre-allocated buffer)")
    Signed-off-by: Kees Cook <keescook@chromium.org>
    Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
    Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
    Acked-by: Scott Branden <scott.branden@broadcom.com>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/20201002173828.2099543-2-keescook@chromium.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/base/firmware_loader/main.c | 5 ++---
    fs/exec.c | 7 ++++---
    include/linux/fs.h | 1 -
    kernel/module.c | 2 +-
    security/integrity/digsig.c | 2 +-
    security/integrity/ima/ima_fs.c | 2 +-
    security/integrity/ima/ima_main.c | 6 ++----
    7 files changed, 11 insertions(+), 14 deletions(-)

    --- a/drivers/base/firmware_loader/main.c
    +++ b/drivers/base/firmware_loader/main.c
    @@ -470,14 +470,12 @@ fw_get_filesystem_firmware(struct device
    int i, len;
    int rc = -ENOENT;
    char *path;
    - enum kernel_read_file_id id = READING_FIRMWARE;
    size_t msize = INT_MAX;
    void *buffer = NULL;

    /* Already populated data member means we're loading into a buffer */
    if (!decompress && fw_priv->data) {
    buffer = fw_priv->data;
    - id = READING_FIRMWARE_PREALLOC_BUFFER;
    msize = fw_priv->allocated_size;
    }

    @@ -501,7 +499,8 @@ fw_get_filesystem_firmware(struct device

    /* load firmware files from the mount namespace of init */
    rc = kernel_read_file_from_path_initns(path, &buffer,
    - &size, msize, id);
    + &size, msize,
    + READING_FIRMWARE);
    if (rc) {
    if (rc != -ENOENT)
    dev_warn(device, "loading %s failed with error %d\n",
    --- a/fs/exec.c
    +++ b/fs/exec.c
    @@ -955,6 +955,7 @@ int kernel_read_file(struct file *file,
    {
    loff_t i_size, pos;
    ssize_t bytes = 0;
    + void *allocated = NULL;
    int ret;

    if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
    @@ -978,8 +979,8 @@ int kernel_read_file(struct file *file,
    goto out;
    }

    - if (id != READING_FIRMWARE_PREALLOC_BUFFER)
    - *buf = vmalloc(i_size);
    + if (!*buf)
    + *buf = allocated = vmalloc(i_size);
    if (!*buf) {
    ret = -ENOMEM;
    goto out;
    @@ -1008,7 +1009,7 @@ int kernel_read_file(struct file *file,

    out_free:
    if (ret < 0) {
    - if (id != READING_FIRMWARE_PREALLOC_BUFFER) {
    + if (allocated) {
    vfree(*buf);
    *buf = NULL;
    }
    --- a/include/linux/fs.h
    +++ b/include/linux/fs.h
    @@ -2861,7 +2861,6 @@ extern int do_pipe_flags(int *, int);
    #define __kernel_read_file_id(id) \
    id(UNKNOWN, unknown) \
    id(FIRMWARE, firmware) \
    - id(FIRMWARE_PREALLOC_BUFFER, firmware) \
    id(MODULE, kernel-module) \
    id(KEXEC_IMAGE, kexec-image) \
    id(KEXEC_INITRAMFS, kexec-initramfs) \
    --- a/kernel/module.c
    +++ b/kernel/module.c
    @@ -4028,7 +4028,7 @@ SYSCALL_DEFINE3(finit_module, int, fd, c
    {
    struct load_info info = { };
    loff_t size;
    - void *hdr;
    + void *hdr = NULL;
    int err;

    err = may_init_module();
    --- a/security/integrity/digsig.c
    +++ b/security/integrity/digsig.c
    @@ -169,7 +169,7 @@ int __init integrity_add_key(const unsig

    int __init integrity_load_x509(const unsigned int id, const char *path)
    {
    - void *data;
    + void *data = NULL;
    loff_t size;
    int rc;
    key_perm_t perm;
    --- a/security/integrity/ima/ima_fs.c
    +++ b/security/integrity/ima/ima_fs.c
    @@ -272,7 +272,7 @@ static const struct file_operations ima_

    static ssize_t ima_read_policy(char *path)
    {
    - void *data;
    + void *data = NULL;
    char *datap;
    loff_t size;
    int rc, pathlen = strlen(path);
    --- a/security/integrity/ima/ima_main.c
    +++ b/security/integrity/ima/ima_main.c
    @@ -621,19 +621,17 @@ void ima_post_path_mknod(struct dentry *
    int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
    {
    /*
    - * READING_FIRMWARE_PREALLOC_BUFFER
    - *
    * Do devices using pre-allocated memory run the risk of the
    * firmware being accessible to the device prior to the completion
    * of IMA's signature verification any more than when using two
    - * buffers?
    + * buffers? It may be desirable to include the buffer address
    + * in this API and walk all the dma_map_single() mappings to check.
    */
    return 0;
    }

    const int read_idmap[READING_MAX_ID] = {
    [READING_FIRMWARE] = FIRMWARE_CHECK,
    - [READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
    [READING_MODULE] = MODULE_CHECK,
    [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
    [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,

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